NETA World Journal | Fall 2012

• Rugged, small and lightweight

• High current, high power (60 Amps/300 VArms) per phase

• Up to 6 currents with convertible channels

• Thermally controlled fans for quiet operation

• New Smart Touch View Interface (STVI) provides manual control

• New STVI Overcurrent Test includes hundreds of relay specific time-curves built-in

With these comprehensive capabilities and extensive testing options the SMRT36 is conceivably the easiest to use 3-phase protective relay test system available today.

For more information on the SMRT36 relay test set contact us today at 1-800-723-2861 or email us at sales@megger.com to receive a SMRT36 brochure and Megger 2012 Power Catalog.

Megger

4271 Bronze Way

Dallas, Texas 75237-1019

COVER STORY

FEATURES

7 PRESIDENT’S DESK

Mose Ramieh, Power & Generation Testing, Inc.

NETA President

46BATTERY MAINTENANCE RECOMMENDATIONS FOR UPS SYSTEMS

By Lynn Hamrick, Shermco Industries

74WHY REPLACE SERVICEABLE BATTERIES?

By Klas Björck, Megger

20 AN OVERVIEW OF BATTERY ASSET MANAGEMENT ISSUES

By

Kenneth Elkinson, Matthew Lawrence & Tony McGrail, Doble Engineering Company

It is a normal Tuesday afternoon with the sounds of people tapping away on their keyboards filling the office. Suddenly the office goes dark, no one can see their screen anymore, business production is halted, and the person in charge of your company’s UPS system knows they have a problem on their hands.

TABLE OF CONTENTS

IN EVERY ISSUE

28MAINTENANCE CORNER

Determining Criticality in an Electrical Maintenance Program

Kerry Heid, Magna Electric Corporation

34TECH QUIZ

Batteries and Battery Chargers

Jim White, Shermco Industries

39THE NFPA 70E AND NETA

Arc-Flash Clothing and PPE

What Does NFPA 70E Say?

Jim White and Ron Widup, Shermco Industries

SPECIFICATIONS AND STANDARDS ACTIVITY

110ANSI/NETA STANDARDS UPDATES

INDUSTRY TOPICS

32REAL WORLD LEARNING AT YOUR FINGERTIPS

NETA Handbooks

54SOLVING RELAY MISOPERATIONS WITH LINE PARAMETER MEASUREMENTS

Will Knapek, OMICRON Electronics Corp USA

60NICHE MARKET TESTING

Data Center Maintenance–Part 1–

The Electrical Maintenance Program

Lynn Hamrick, Shermco Industries

66TESTING ROTATING MACHINERY

Current Signature Analysis (CSA) Test

Vicki Warren and Ian Culbert, Iris Power LP.

89TECHNICAL BRIEF

Capacitor Trip Unit

Jim Bowen, Powell Industries

92SAFETY CORNER

Battery Safety Concerns

Stephen Canale, American Electrical Testing Co.

101TECH TIPS

Current Distribution in Resistivity Measurement

Jeff Jowett, Megger

80WHAT DO I DO IF THE BREAKER TRIPS?

James R. White, Training Director, Shermco Industries, Inc.

NETA NEWS

10WHEN GOOD IS NOT GOOD ENOUGH By Jill Howell & Kristen Wicks

16NETA BOARD AND PROMOTIONSCOMMITTEE CONVENEINCANADA

By Kristen Wicks

114NETA ACCREDITED COMPANIES

120ADVERTISER LIST

3050 Old Centre Avenue, Suite 102

Portage, MI 49024

Toll free: 888.300.NETA (6382)

Phone: 269.488.NETA (6382)

Fax: 269.488.6383

neta@netaworld.org

www.netaworld.org

EXECUTIVEDIRECTOR: Jayne Tanz, CMP

NETA Officers

PRESIDENT: Mose Ramieh, Power & Generation Testing, Inc.

FIRSTVICEPRESIDENT: David Huffman, Power Systems Testing Co.

SECONDVICEPRESIDENT: Ron Widup, Shermco Industries

SECRETARY: Walt Cleary, Burlington Electrical Testing Co., Inc.

TREASURER: John White, Sigma Six Solutions

NETA Board of Directors

Ken Bassett (Potomac Testing, Inc.)

Scott Blizard (American Electrical Testing Co., Inc.)

Jim Cialdea (Three-C Electrical Co., Inc.)

Walt Cleary (Burlington Electrical Testing Co., Inc.)

Roderic Hageman (PRIT Service, Inc.)

Kerry Heid (Magna Electric Corporation)

David Huffman (Power Systems Testing)

Alan Peterson (Utility Service Corporation)

Mose Ramieh (Power & Generation Testing, Inc.)

John White (Sigma Six Solutions)

Ron Widup (Shermco Industries)

NETA World Staff

TECHNICALEDITOR: Roderic L. Hageman

ASSOCIATEEDITORS: Diane W. Hageman, Resa Pickel

MANAGINGEDITOR: Jayne Tanz, CMP

ADVERTISINGMANAGER: Sara M. G. Dillon

DESIGNANDPRODUCTION: Newhall Klein, Inc.

NETA Committee Chairs

CONFERENCE: Ron Widup; MEMBERSHIP: Ken Bassett; PROMOTIONS/MARKETING: Kerry Heid; SAFETY: Lynn Hamrick; TECHNICAL: Alan Peterson; TECHNICALEXAM: Ron Widup; WORLDADVISORY: Diane Hageman; CONTINUINGTECHNICALDEVELOPMENT: David Huffman; TRAINING: Kerry Heid; FINANCE: John White; NOMINATIONS: Alan Peterson; STRATEGY: Mose Ramieh; AFFILIATEPROGRAM: Jim Cialdea

© Copyright 2012, NETA

NOTICE AND DISCLAIMER

NETA World is published quarterly by the InterNational Electrical Testing Association. Opinions, views and conclusions expressed in articles herein are those of the authors and not necessarily those of NETA. Publication herein does not constitute or imply endorsement of any opinion, product, or service by NETA, its directors, officers, members, employees or agents (herein “NETA”).

All technical data in this publication reflects the experience of individuals using specific tools, products, equipment and components under specific conditions and circumstances which may or may not be fully reported and over which NETA has neither exercised nor reserved control. Such data has not been independently tested or otherwise verified by NETA.

NETA MAKES NO ENDORSEMENT, REPRESENTATION OR WARRANTY AS TO ANY OPINION, PRODUCT OR SERVICE REFERENCED OR ADVERTISED IN THIS PUBLICATION. NETA EXPRESSLY DISCLAIMS ANY AND ALL LIABILITY TO ANY CONSUMER, PURCHASER OR ANY OTHER PERSON USING ANY PRODUCT OR SERVICE REFERENCED OR ADVERTISED HEREIN FOR ANY INJURIES OR DAMAGES OF ANY KIND WHATSOEVER, INCLUDING, BUT NOT LIMITED TO ANY CONSEQUENTIAL, PUNITIVE, SPECIAL, INCIDENTAL, DIRECT OR INDIRECT DAMAGES. NETA FURTHER DISCLAIMS ANY AND ALL WARRANTIES, EXPRESS OF IMPLIED, INCLUDING, BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE.

ELECTRICAL TESTING SHALL BE PERFORMED ONLY BY TRAINED ELECTRICAL PERSONNEL AND SHALL BE SUPERVISED BY NETA CERTIFIED TECHNICIANS/ LEVEL III OR IV OR BY NICET CERTIFIED TECHNICIANS IN ELECTRICAL TESTING TECHNOLOGY/LEVEL III OR IV. FAILURE TO ADHERE TO ADEQUATE TRAINING, SAFETY REQUIREMENTS, AND APPLICABLE PROCEDURES MAY RESULT IN LOSS OF PRODUCTION, CATASTROPHIC EQUIPMENT FAILURE, SERIOUS INJURY OR DEATH.

My how time flies. It seems like just yesterday I was elected as your president, but I’m now in the second year of my term. This edition of NETA World is addressing an issue that can have the same short time frame thoughts associated with it.

How long has it been since your batteries were serviced? It seems like just yesterday they were installed, and tested, and didn’t you just check the water and clean them? Find out all the important aspects of keeping battery systems in tip top shape in this edition.

This year has been an exciting one for NETA. Our 40th Anniversary at the over the top conference in Texas, four (4) new NETA Accredited Companies (NAC), ANSI/NETA Acceptance Specifications accepted by major engineering and construction firms, the implementation of the NAMO program, and more. All of these successes have come through the work of a few volunteers and the NETA Staff. We owe these hard working folks a well-deserved pat on the back.

The Board of Directors held a Strategic Planning Committee meeting followed by a Marketing Committee meeting during the month of June. These two meetings have given us the frame work to continue the evolution and expansion of NETA’s influence. In the next few months meetings will be held with several large constructors, A & E firms, and insurance companies. The purpose of the meetings is to promote our standards and encourage the use of NETA Accredited Companies to perform the work associated with the testing specifications. Your input and support is critical to the success of NETA and these initiatives. Let us hear from you!

Fall is approaching and with it the political season will be in full swing. Hopefully, after the election the economy will settle down and with it an uptick in our business. Be sure you get out and exercise your right to vote.

Mose Ramieh

NETA

President

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WHEN GOOD IS NOT GOOD ENOUGH

BY JILL HOWELL AND KRISTEN WICKS

In recent years it has become common practice to think that good is good enough. However, with the demands placed on product and service providers in today’s global market, in many situations good is nowhere near good enough. In certain contexts, particularly in the realm of risk management and liability, even 99 percent assurance is not good enough. Work performed in the electrical power systems industry is one of those fields where one can never be too careful or take for granted the importance of standards that ensure the highest level of safety and reliability.

If 99 percent assurance were good enough: parents daily. written this year. performed incorrectly.

…And in the case of the electrical power systems in the U.S. may be at risk of failure incident or potentially causing serious injury.

1. Independent Statistics & Analysis, U.S. Energy Information Administration; How many and what kind of power plants are there in the United States?; December 21, 2011.

PUTTING QUALITY AND SAFETY FIRST

NETA’s mission is to ensure that the electrical power industry is as safe and reliable as possible. NETA’s foundation is built firmly on its third-party, independent NETA Accredited Companies that perform field testing services in accordance with the ANSI/NETA standards for maintenance and acceptance testing specifications (ANSI/NETA MTS and ANSI/ NETA ATS).

Third-party, independent testing provides an unparalleled level of unbiased service. Each NETA Accredited Company is committed to verifying the soundness of electrical power systems and reporting on their findings without the inherent conflict of interest that exists when field testing

is performed by equipment manufacturers, installers, and other parties with divided interests. NETA Accredited Companies are examined during the application process and through ongoing peer review to assure that NETA’s requirements for independence, safety, calibration, test reports, and most importantly, technician qualification and continuing education, are maintained to the highest standard.

NETA also understands that testing is only one aspect of ensuring electrical power system safety and reliability. Without the participation of the many business sectors that comprise the electrical power industry, a 100 percent assurance of safety and reliability is unobtainable. With that knowledge, NETA formed the NETA Affiliate Program.

The NETA Affiliate Program was established with the goal of engaging individuals rather than companies in the pursuit of improving safety and reliability in the industry. The Affiliate Program is subscription-based, meaning that there are no prerequisites or credentials necessary to become an Affiliate. While there is not a certification or qualification attached to being a NETA Affiliate, this program is home to professionals who share NETA’s mission, leaders who bring perspectives from all sectors of the electrical power industry and those who put quality and safety first.

NETA Affiliates are comprised of representatives from all sectors of our industry, such as:

The goal of the NETA Affiliate Program is to build a network of industry professionals committed to promoting and improving safety and reliability within the electrical power industry.

NETA is expanding the program adding initiatives and activities that encourage Affiliate involvement and participation in educational events and in promoting safety. More interaction through expanded networking and business development opportunities allow Affiliates to be more connected to NETA, other industry organizations, and the ever-changing dynamics of this industry. As a result, the NETA Affiliate Program now includes representation among associations such as NFPA, IAEI, AIA, IEEE, and companies and organizations that are shaping and influencing every aspect of the electrical power systems world.

Whether you are currently a NETA Affiliate or will be joining the program, you are encouraged to participate as often as possible and to provide your ideas on how to make the program even better.

One of the first NETA Member and Affiliate events will be the launch of the NETA Affiliate Newsletter, scheduled for October 1, 2012. NETA Affiliates are also invited to attend the February Member and Affiliate Luncheon scheduled for Monday, February 18, 2013, during PowerTest 2013 in New Orleans, Louisiana. Affiliates will join NETA members for a sit down lunch. The agenda includes an update on the association's activities and the announcement of the 2013 Affiliate of the Year. Throughout the luncheon, Members and Affiliates have the opportunity to rub elbows and share stories.

NETA will launch the first NETA Affiliate Newsletter with the goal of providing our Members and Affiliates with opportunities to share technological and business news. Topics will include:

Mark Your Calendars –2012-2013 NETA Affiliate Events

• NETA Affiliate Newsletter Launch; October 1, 2012

• NETA Website Affiliate Section Launch; January 1, 2013

• PowerTest 2013 – NETA Member and Affiliate Luncheon; New Orleans, Louisiana; February 18, 2013

• Affiliate of the Year Award; February 18, 2013

Congratulations to Dennis Neitzel 2012 NETA Affiliate of the Year!

• News about NETA, NETA events, and NETA standards

• A summary of what is happening in the industry regarding

• Industry standards

• Safety training

• Technical training

• A forum for Affiliates to present press releases, new product information, and updates on new technology

Another area in which Affiliates have requested NETA’s assistance is with training. Over the next twelve months, NETA will work to develop course specification and networking with select training organizations to expand course curriculum. These courses will provide Affiliates more educational options that qualify for AIA, IEEE, and general continuing educational credits for organizations outside of NETA.

To support these new initiatives and encourage Affiliate involvement, NETA will launch a dedicated section on the netaworld.org website designed to provide Affiliates with a forum to access and share information and exchange ideas.

Join the neta Community!

NETA and its Accredited companies are extremely excited about the new developments planned for the NETA Affiliate Program. If you are currently an Affiliate, stay tuned for news on these new opportunities in the coming months.

If you are not currently an Affiliate, join today at netaworld.org. We look forward to meeting you and welcoming you to our network of professionals.

If you have additional questions, please feel free to contact Jim cialdea, Affiliate committee chair, or Jill Howell, NETA Staff Liaison.

Jim cialdea

Affiliate committee chair

Three-c Electrical co., Inc. 508-881-3911 jim@three-c.com

Jill Howell

NETA Staff Liaison

Marketing and communications Manager Direct: 888-300-6394 Main: 888-300-6382 jhowell@netaworld.org

The following table provides a visual representation of all the aspects required for the various levels of participation within NETA.

To view the most current listing of NETA Accredited companies, the source for third-party, independent electrical testing, please visit www.netaworld.org or contact the NETA office at neta@netaworld.org.

Introducing a really big idea: “Rent it”

What makes it work, better than what you’re doing now? What’s next? You need a plan

NETA BOARD AND PROMOTIONS COMMITTEE

BY KRISTEN WICKS

June in Regina, Saskatchewan is a great time of year. Contrary to the misguided belief that the land north of the United States border is buried in snow year round, the weather was pleasant and welcoming to NETA’sBoardofDirectorsandPromotionsand NETA’s Board of Directors and Promotions and Marketing Committee for their meetings on June 2122, 2012. Kerry Heid, Magna Electric Corporation, and his wife, Pam, hosted the entire crew at their home for a family style dinner complete with a gorgeous sunset. Another highlight of the meeting was a visit to the Royal Canadian Mounted Police Training Academy in Regina, Saskatchewan, for a private guided tour of the grounds and museum anddinner. and dinner.

The regal atmosphere of the Hotel Saskatchewan, proud host to Queen Elizabeth, was the setting for some very exciting and dynamic planning for the association at the Board of Director’s strategy session. The Promotions and Marketing Committee reported a successful year of executing the plan established in 2012, and looks forward to further expansion of the outreach efforts at the NETA office with the support of the NETA Accredited Companies. NETA is pleased to continue to offer new programs and benefits to its members.

Outside and Inside Views of the Royal Canadian Mounted Police Chapel, Built in 1883.

Top Photo: The NETA Board and Staff Outside Royal Canadian Mounted Police Museum. Below Photos, Clockwise from Left: Stained Glass Window in RCMP Chapel, Memorial at RCMP Training Academy, and BoardDiscussion. Board Discussion.

AN OVERVIEW OF BATTERY ASSET MANAGEMENT ISSUES

BY KENNETH ELKINSON, MATTHEW LAWRENCE AND TONY MCGRAIL, Doble Engineering Company

It is a normal Tuesday afternoon with the sounds of people tapping away on their keyboards filling the office. Suddenly the office goes dark, no one can see their screen anymore, business production is halted, and the person in charge of your company’s UPS system knows they have a problem on their hands.

In general, the hope is that the UPS or battery system goes unnoticed by most. It will spend most of its lifetime operating in standby, waiting for its chance to shine. It is that small fraction of time, however, when it is called upon to operate a circuit breaker, or pick up the load of a building when the utility power goes out, that a battery system can be the most important piece of equipment on the property. The battery system needs to be correctly sized and maintained throughout its life cycle. If it was not correctly sized or maintained, when it is called upon to operate, everyone will notice.

Assuming that the battery was properly sized for its intended load, maintaining the battery becomes key to ensuring the battery will perform as designed. A typical battery bank is shown in Figure 1. Something as simple as a monthly or bimonthly visual inspection of the battery and its charger can provide a great amount of information. As these inspections are performed, it is vital to take note of the electrolyte levels; of any corrosion on the terminals, connectors, racks, or cabinets; and if there is any visible evidence of damage, such as cracks or leaks in the cells 2 as shown in Figure 2.

The battery temperature should be recorded along with the float and equalize charges. Care should be taken to ensure that the battery is not in an area of sunlight or near a heater.

Figure 1: Typical Battery Bank

Figure 2: Battery Cell with Cracks

Since power is such a critical aspect of our lives and society today, most anything that helps keep the lights on is fair game for online monitoring, even battery systems.

The battery temperature should be recorded along with the float and equalize charges. Care should be taken to ensure that the battery is not in an area of sunlight or near a heater. As shown below in Figure 3, temperature can have a significant impact on battery life, especially as the ambient temperature rises. All of these items observed during the visual checks should stay relatively consistent over time, and they can provide a good indication if any cells of the battery have degraded, or cannot be relied on.1 , 2

These simple checks can be so critical to a battery system that the North American Electric Reliability Council (NERC) has mandated they be done regularly for bulk supply points on the transmission system. NERC has provided definitions for monitored, unmonitored, and continuously monitored battery systems and has mandated that test procedures correspond to the type of battery system that is installed. NERC also mandates that utilities have documented maintenance programs with established maintenance intervals for these key bulk supply points, and penalties can be levied when the maintenance programs are not followed. 3

Figure 3: Temperature Effects on Battery Life and Capacity

Batteries are relatively low cost items when compared with other assets in a substation. Depending on the battery size and transformer size in the same substation, the battery may cost 0.1 percent of what the transformer costs, but its job is just as crucial as it provides power to the equipment that protects the transformer from system faults. Battery systems may have life expectancies of approximately 20 years. This may be only half of what the transformer life expectancy is, but the cost comparison will still not rise above 0.2 percent of the cost of the transformer it is there to help protect.

Monitoring has long been an accepted practice for extending the useful life of an apparatus. On-line monitoring has gained traction in recent years with the development of new technologies combined with the decline in price of communication equipment. Since power is such a critical aspect of our lives and society today, most anything that helps keep the lights on is fair game for on-line monitoring, even battery systems, as shown in Figure 3.

Monitoring systems and their accompanying software are now available to perform real time analysis on events such as discharges, system voltage issues, and thermal runaway and to alert when the analysis discovers trends that indicate a failing or problematic unit. The benefit of this type of monitoring is that problems can be detected in real time and, hopefully, corrected before the battery system fails and cannot perform its duty when called to do so. Batteries have certain failure modes that cause the battery to rapidly deteriorate, and it is possible that the visual monthly checks may not be frequent enough to predict that a battery is failing before it actually fails.

It becomes fairly obvious that monthly visual inspections of all batteries on a system can generate a mountain of information. Over time, as multiple inspections on a battery system are performed, the trend becomes just as important as the actual data itself. Ideally, the battery owner will have a system in place that will accept the monthly inspection data, trend the results over time, and

run analytics on the data to alert when a battery is trending towards a set of predetermined limits. This becomes particularly important when one person or a small group is charged with managing a fleet of battery systems over a large geographical area. It can become very difficult to keep track of which batteries need the most attention, which are nearing the end of their useful life, and which should be on the short list of replacement candidates in the next year, five years, and ten years. 4

A software system, such as dobleARMS™ (Figure 4) that combines on-line, off-line, and real time data from various substation apparatus, and per-

Figure 5: Software Combining On-line, Off-line, and Real Time Data for Analysis of Asset Condition

Figure 4: Battery Bank with On-Line Monitoring System Installed

form powerful analytics can generate alerts and rankings of assets based on this data. It can be programmed to alert the user when any asset is in danger. Managing NERC compliance data for batteries becomes an issue which is manageable with the use of data management software as part of an overall risk system.

In the end, as with just about everything else, battery systems relate back to money. Battery systems are there to provide a backup source of power for when things go wrong. Utilities track customer outages and customer outage minutes, and must report these as key performance indicators (KPI) to their regulators. One major utility estimates that their average customer interruptions due to battery issues are 6,000, and customer minute interruptions are estimated at 70,000. Assuming two interruptions per year, this would put their System Average Interruption Frequency Index, SAIFI, number at 0.0038, and their System Average Interruption Duration Index, SAIDI, number at 0.044. If they were to do away with their battery maintenance and monitoring program, they estimate their SAIFI number would increase to 0.008, and their SAIDI number would increase to 0.09. There is little doubt that their regulators would notice an increase of greater than 100 percent in customer interruptions. With this increase would come significant financial penalties, all due to not maintaining the battery systems. 5

It has been stated that energy storage could be the most influential, game-changing development the electrical world will see in the coming century. 6 Many businesses and government agencies today have realized this and also realized how costly an unexpected power interruption would be to their respective organizations. Just looking at today’s electronic devices, it is easy to see how much we already depend on batteries, and our dependence on batteries will only grow in the future.

Dr. Tony McGrail is the SFRA Product Manager at Doble Engineering. Over the last three years he has developed new SFRA applications and instruments and provided research into analysis techniques for SFRA traces. Prior to joining Doble, McGrail was a transformer engineer with the National Grid Company in the UK. This encompassed both fieldwork in transformer testing and assessment and the development of leading-edge analytical techniques for transformer health studies. He received his bachelor’s degree in physics, a subsequent master’s degree in instrument design and application, and his PhD in electrical engineering.

Kenneth Elkinson is the SFRA Product Manager at Doble Engineering. Over the last three years he has developed new SFRA applications and instruments and provided research into analysis techniques for SFRA traces. Prior to joining Doble, McGrail was a transformer engineer with the National Grid Company in the UK. This encompassed both fieldwork in transformer testing and assessment and the development of leading-edge analytical techniques for transformer health studies. He received his bachelor’s degree in physics, a subsequent master’s degree in instrument design and application, and his PhD in electrical engineering.

Matthew B. Lawrence is the Solutions Manager, SFRA and Circuit Breaker Diagnostics at Doble Engineering Company, focusing on diagnostic testing solutions. Before joining Doble in 2011, Mr. Lawrence held positions in substation maintenance and operations and equipment maintenance engineering departments at National Grid and its New England-based legacy companies. Mr. Lawrence is a member and past chair of the Doble Engineering SFRA Users Group and has coauthored numerous papers on field transformer testing and condition assessment. Mr. Lawrence holds an Associates of Science Degree in Electronics Engineering from New England Institute of Technology and attended Worcester Polytechnic Institute’s School of Industrial Management. He is also an active member in IEEE/PES.

1 As detailed at the Circuit Breaker Battery Tutorial, 80th Annual International Conference of Doble Clients, Boston MA, USA 2011

2 Hydroelectric Research and Technical Services Group, “Storage Battery Maintenance and Principles”, June 1998

3 North American Electric Reliability Council, Protection System Maintenance, Draft Supplementary Reference, November 17, 2010, Prepared by the Protection System Maintenance and Testing Standard Drafting Team, PRC-005-2, Project 2007-17

4 A. McGrail “Data and Decisions”, IEEE Smart Grid Conference, Perth 2011

5 J. Afonso, V. Forte., J. Grimsley, T., McGrail, “Asset Management: From Assets to KPI’s”, 4th EPRI International Conference on Asset Management, Chicago, USA, 2008

6 As detailed at Roundtable Discussion, CIGRE Game Changer’s Symposium, Atlanta, GA November 2011

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DETERMINING CRITICALITY IN AN ELECTRICAL MAINTENANCE PROGRAM

BY KERRY HEID, Magna Electric Corporation

INTRODUCTION

Worker safety is highly dependent on electrical systems operating exactly as they were designed to operate. Much concentration is put on ensuring that equipment meets stringent codes and standards. One reason for this is to ensure that electrical systems limit worker exposure to arc-flash and shock hazards.

If this is so extremely important to worker safety at the time of design and installation, why is maintenance of the equipment to provide integrity of those standards not always given the same scrutiny? It has become more evident with the new safety

standards that equipment must operate in like new condition or serious threats to workers safety may result.

Realizing this, it is very important for facility managers to put an increased reliability requirement on certain systems that directly impact worker protection from arc flash and shock. This requirement for reliability is quite different than that for uptime or production purposes. Equipment required for electrical hazard mitigation applications can fail undetected, and the loss of protective capabilities may not be known until an injury occurs. Any maintenance program should be designed to address maintenance of equipment critical for electrical safety.

High Priority - Circuit Breaker Maintenance

Determining personal protective equipment requirements for flash hazards is based primarily on the overcurrent protective systems functioning exactly as designed. Therefore a robust maintenance management system must be established to assure no deviation from the expected operation of those systems. If the protection systems do not operate as designed, thermal and blast energy may be orders of magnitude higher than expected.

TOP FIVE SAFETY-RELATED CRITICAL MAINTENANCE ITEMS

The following top five items represent the opinion of the author based on recent reliability data, service experience, probability of failure, and consequence to worker safety.

1. CIRCUIT BREAKERS

These devices have been ranked #1, often being culprits in affecting both the incident energy as well as the shock hazard. A recent NETA survey showed that, when performing maintenance testing, over 22 percent of these devices do not operate as designed and 10 percent do not operate at all. The problem with these devices is that they will fail to operate correctly over time and without notice. When they are required to operate during a fault or even during regular switching, they do not.

2. PROTECTIVE RELAY SYSTEMS

These systems are ranked high because they are the systems that respond quickly during a fault scenario. While many times the maintenance issues are with the performance of the hardware, a lot of times the problems are with the settings. Sometimes the settings were not developed correctly from the first installation, particularly in more complex microprocessor-based relays. Often the settings have been adjusted or defeated in the field. In any of these cases, the arc-flash hazard can drastically increase from what is expected leaving workers in highly hazardous situations they do not anticipate.

3. TRIPPING POWER

Catastrophic damage has been witnessed when the power utilized to operate the protective scheme does not function. The problems range from an entire dc system loss to individual switchgear cell or device issues. The extreme hazard exists as the entire protective system is defeated. Incident energy will be greater than expected and there may be substantial loss of equipment due to fire.

4. GROUND FAULT PROTECTION SYSTEMS

Ground fault protection systems including neutral grounding devices, sensors, control wiring, and isolation devices are designed for protective functions to provide worker safety. Failure of these systems can substantially increase arc-flash and shock hazards when not maintained properly.

5. GROUNDING AND BONDING SYSTEMS

These systems are ranked number 5 but are still very important, primarily in preventing the electrical shock hazard. In many cases a simple visual inspection can determine that the connections are deteriorating or missing (copper grounding is a common theft item). There are cases when the step and touch potentials and associated ground potential rise will become a shock hazard. This happens as the ground systems deteriorate in conjunction with an increase in utility fault current.

The gotcha in all cases is that these systems fail, undetected, along with their capability to provide a safe working environment. This is much different than a mechanical failure where normally the issues are easily seen or detected through visual inspection or vibration sensors.

NOTE: Devices such as transformers, cables, capacitors and motors do not have the same impact on worker safety as the five items listed above. However, these devices will have increased hazards when one of the safety-related critical maintenance items does not operate.

Safety-Related Critical Maintenance

Utilizing a professionalNET ofessional NETAA A Accredited edited Company with the latest NETAM A Maintenance Testing Specifications helps to ensurethe e the power system equipment will function as designed to protect workers.

CONCLUSION

Electrical maintenance, critical to worker safety, should be performed regardless of reliability and productivity strategies. The arc-flash and shock protection of workers depends on it. Items such as circuit breakers, protective relay systems, and ground fault systems, should be inspected and tested on intervals determined by experience and prior test and inspection data if they are to operate exactly as originally designed. The failure of these items is often undetected until a serious event occurs putting workers in dangerous situations they do not anticipate. Utilizing a professional NETAAccredited Company with the latest NETA Maintenance Testing Specifications helps to ensure the power system equipment will function as designed to protect workers.

Kerry Heid is the President of Magna Electric Corporation, a Canadian-based electrical projects group providing NETA Certified Test Technicians and related products and solutions for electrical power distribution systems. Kerry is a past President of NETA (InterNational Electrical Testing Association) and has been serving on its board of directors since 2002. Kerry is chair of NETA’s training committee and is a Senior Certified Test Technician Level IV. Kerry was awarded NETA’s 2010 Outstanding Achievement Award for his contributions to the association.

Kerry is the chair of CSA Z463 Technical Committee on Maintenance of Electrical Systems. He is also a member of the executive on the CSA Z462 technical committee for Workplace Electrical Safety in Canada and is chair of Working Group 6 on safety-related maintenance requirements as well as a member of the NFPA 70E – CSA Z462 harmonization working group.

Kerry has performed electrical engineering, testing, maintenance, commissioning, and training activities throughout North America for the past 23 years with Westinghouse Service and Magna Electric Corporation. He resides in Regina, Saskatchewan, with wife Pam and sons Brendan and Colby.

REAL WORLD LEARNING A T

YOUR FINGER TIPS

In 2012 NETA celebrates 40 years of service to the electrical systems industry – Establishing industry standards and delivering leading-edge technical information and educational resources based on real-world experience.

NETA was founded with the goal of advancing the industry’s focus on safety and reliability. The Association’s contribution is fullfilled through the development of the ANSI/NETA Standards and the creation of educational and training resources that include the NETA Self-Paced Technical Seminars, the annual PowerTest conferences, the quarterly NETA World Journal, as well as a 14 volume series of NETA Handbooks.

The NETA Handbooks were first released as a series in 2009. They are a go-to source for highly relevant information about testing procedures, troubleshooting, and real-life solutions to situations encountered everyday in the field. The Handbooks were initially created in response to requests from the electrical industry, the general public, NETA

Accredited Companies, and NETA’s technical community seeking a comprehensive, subjectspecific technical resource to use for training and reference materials.

A SALUTE TO NETA’S MANY AUTHORS

All NETA technical materials, publications, and events are authored by industry experts – leadingedge, highly knowledgeable individuals who have many years of experience in the field. NETA is extremely grateful for their contributions.

The NETA Handbooks bring together a collection of over 200 of the very best articles from past issues of NETA World Journal and the most well- received technical presentations from past PowerTest events.

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BATTERIES AND BATTERY CHARGERS

BY JIM WHITE, Shermco Industries

James R. (Jim) White is the Training Director of Shermco Industries, Inc., in Dallas, Texas. He is the principal member on the NFPA technical committee

“Recommended Practice for Electrical Equipment Maintenance” (NFPA 70B). Jim represents NETA as an alternate member of the NFPA Technical Committee

“Electrical Safety in the Workplace” (NFPA 70E) and represents NETA on the ASTM F18 Committee “Electrical Protective Equipment For Workers”. Jim is an IEEE Senior Member and in 2011 received the IEEE/ PCIC Electrical Safety Excellence award. Jim is a past Chairman (2008) of the IEEE Electrical Safety Workshop (ESW).

Batteries and the supporting charging equipment can easily be overlooked until they are needed. Most facilities use a battery bank to supply dc operating current for opening and closing circuit breakers, spring-charging motors, and indicators. Without the dc supply, circuit breakers will not operate.

1. An indication that a vented lead-acid battery is in trouble is when its internal impedance increases ___% above its as-installed impedance.

a. 5%

b. 20%

c. 30%

d. 45%

2. Which of the following is not an example of a VRLA (valve-regulated lead-acid) battery?

a. nickel-metal hydride

b. gel cells

c. absorbed glass mat

d. maintenance free

3. Sulfation in flooded-cell, lead-acid batteries is indicated by:

a. streaks of oil on the surface of the electrolyte.

b. brownish nodules adhering to the case.

c. white salts appearing on the surface of the plates.

d. white milky substance that appears on the cells and jar.

4. When performing a load test on a battery bank, what percent remaining capacity indicates the need to replace the batteries?

a. 20%

b. 40%

c. 60%

d. 80%

5. The only repair for sulfation is to:

a. equalize and increase float voltage.

b. use a mixture of boric acid and potassium hydroxide.

c. replace the batteries with new ones.

d. retighten all intercell connections.

No.

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ARC-FLASH CLOTHING AND PPE WHAT DOES NFPA 70E SAY?

BY JIM WHITE AND RON WIDUP, ShermcoIndustries Shermco Industries

NFPA 70E has a wide following in the electrical industry and with good reason. Not only is it generally considered the latest word on protecting electrical workers, but OSHA recommends it as a guide for meeting the federal regulations. It provides proven and workable safe work practices and has been used as the basis for development of other country’s electrical safety standards and regulations.

What does the latest [2012] edition of NFPA 70E have to say about arc-rated PPE?

We will take a look at several nuggets of information within the 70E to explain further.

Informational Note

No. 2: See Table 130.7(C)(15)(a) and Table 130.7(C)(15)(b) for examples of activities that could pose an arc-flash hazard.

Usually, guarded equipment does not pose a hazard from arc flash, but when interacting with electrical equipment in a manner that could cause failure the arc-flash hazard has to be considered, even though there are no exposed energized conductors or circuit parts. This is why Informational Note No. 2 provides guidance regarding activities that may fall in to this category.

We have dicussed it previously, but close attention should be paid to Article 100, Definitions. If you read and understand the definitions, it will help to understand the standard in a more comprehensive and complete manner.

INFORMATION FOUND IN

Informational Note

No. 1: An arc-flash hazard may exist when energized electrical conductors or circuit parts are exposed or when they are within equipment in a guarded or enclosed condition, provided a person is interacting with the equipment in such a manner that could cause an electric arc. Under normal operating conditions, enclosed energized equipment that has been properly installed and maintained is not likely to pose an arcflash hazard.

It is also important to note that equipment in normal operation, installed in accordance with the NEC and other applicable codes and standards, along with being maintained correctly in accordance with manufacturer’s recommenda-tions and industry consensus standards (such as the ANSI/NETA maintenance testing standard), does not pose an arc-flash hazard. This does not mean there is no possibility of an arc flash, just that the possibility is small. If for any reason the equipment is suspect (such as during troubleshooting) wearing additional arc-rated PPE is probably in order. Remember, it all goes back to the hazard assessment.

Arc-rated clothing or equipment indicates that it has been tested for exposure to an electric arc. Flame-resistant (FR) clothing without an arc rating has not been tested for exposure to an electric arc. d finind the derstand hensive and gized con Inf g uida fall I plic wi a

THE NFPA 70E AND NETA

This is to differentiate an electrical worker’s protective clothing and PPE from that worn by other trades that require flame-resistant clothing such as steel mills, oil and gas, firefighters, etc. They may have FR clothing, but it may not be rated for exposure to electrical arcs.

INFORMATION FOUND

INVOLVING ELECTRICAL HAZARDS

Analysis. Where it has been determined that work will be performed within the

arc flash boundary, one of the following methods shall be used for the selection of protective clothing and other personal protective equipment (PPE):

130.7(C)(15) and 130.7(C)(16)]

The most widely-preferred method for choosing arc-rated clothing and PPE is to have an arc flash hazard analysis performed and have the equipment labeled. However, there are many facilities where that just is not going to happen, so the tables in Section 130.7 can be used instead. Be aware that neither method is foolproof and both have drawbacks, but the arcflash hazard analysis is the best we have right now for determining the correct levels of PPE. It will likely be improved once the findings of the IEEE/NFPA Joint Collaboration Arc-Flash Research Project are released.

Equipment

…….When an employee is working within the arc-flash boundary, he or she shall wear protective clothing and other personal protective equipment in accordance with 130.5. All parts of the body inside the arcflash boundary shall be protected.

Section 130.5 covers the arc-flash hazard analysis or the use of the tables. Note that all parts of the body are to be protected if they inside the arcflash boundary. Hands, ears, eyes, etc. All PPE and clothing specified in tables 130.7(C)(16) or Annex H.3(b) must be worn.

Rather than cover each item in this section, let’s skip down to Article Arm Protection. Maintenance and Use which states, “Electrical protective equipment shall be maintained in a safe, reliable condition. …….”

Arc-flash PPE and clothing must be stored, laundered, and used properly in order to provide adequate protection from an arc flash. This

Figure 1: It Was Too Big To Fit in a Trash Bag

is really where we want to go in this article. How do we care for and use arc-rated PPE and clothing so it remains reliable?

YOUR LIFE DEPENDS ON IT.

Your life does depend on it! Rolling arc-rated flash suits into a knot, cramming it into a bag or leaving it out to collect dust is not maintaining it (Figure 1). It should be inspected, folded and placed in a suitable container, either a locker or a garment bag. All hook and loop (Vel-

cro®) fasteners should be closed so they are not exposed to lint and dirt. If it gets oil or grease on it, other than just a few spots, launder it. It can be laundered at home, but it must be laundered separately. Just follow the manufacturer’s instructions.

RULE 2: LAYERING REDUCES THE POSSIBILITY OF BURNS.

If you thought that arc-rated PPE provides the level of protection for the incident energy

Figure 2: Troubleshooting Electrical Equipment is Hazardous Work

THE NFPA 70E AND NETA

embroidered in or on the label, think about this: ASTM F1959 states that at the rated incident energy of arc-rated clothing or PPE for 1/10th of a second there is a 50 percent probability of a second-degree burn on bare skin underneath it. This applies to arc-rated face shields and arc-rated windows as well. If you suspect that the electrical equipment you are about to work on may have issues, for instance when troubleshooting, wear extra layers of PPE. Think of equipment that requires troubleshooting as being in distress; it is no longer operating

normally and you need to wear the maximum recommended arc-rated clothing and PPE when you troubleshoot it. Wearing cotton or arc-rated underlayers provides additional protection from burns.

RULE 3: INSPECT YOUR ARC-RATED CLOTHING AND PPE PRIOR TO USING IT.

Look for any rips, tears, or openings in either the outer layer or the inner layer. On multilayer flash suits all layers are important to meet the

Figure 3: Come On, Baby, You Can Do It!

identified arc rating. The inside is as important as the outside. Look for seams that are coming loose, especially in the armpits and the crotch. These are high-stress areas and must also be inspected inside the garment as well as on the outside. Inspect the sewing along zippers and Velcro® to ensure they are not curling or becoming detached. If they are, they won’t seal properly. Grease spots larger than about one inch or so in diameter will probably require laundering as grease, oil, and other lubricants increase heat transfer through the fabric. Check the label to make certain it meets ASTM F1505 and NFPA 70E. Also make certain the arc rating is sufficient for your exposure.

On arc-rated face shields and hoods, make certain the face shield is secure to the hard hat. Look for excessive scratching in the viewing area (not to the sides). Excessive means that it limits your vision so you cannot see clearly. Make certain the hard hat suspension is secured inside the hard hat and that the sweat band is not cracked or broken. Ensure any extensions on the arc-rated face shield are secured properly with all needed fasteners, and never use an arc-rated face shield without the chin cup. Some face shields are rated with the chin cup and some without. Not wearing the chin cup would allow the arc plasma to roll up your chest and under the face shield. Inspect the arc-rated windows on arcrated hoods to ensure there are no gaps around them. If the Velcro® is missing in the upper corners an arc flash may cause a burn to the top of your head. Inspect the hood for cuts, rips, tears, grease or oil spots, loose seams, etc., just like the flash suit itself.

LIMITATIONS OF YOUR EQUIPMENT AND PPE.

Exceeding the limitations of your protective clothing and equipment, or your tools and meters, for that matter, is a sure way to be injured or killed. We love the old movies where the pilot is trying to get his plane over the mountain peak and he’s saying, “Come on, girl! Come

on, baby! I know you can do it! Don’t let me down!” Invariably he makes it, but in real life the local authorities would be mounting an expedition to rescue survivors, Figure 3. Don’t think inanimate objects hear you or care about you. Know your own limitations as well. If you are sick, tired, or distracted by crushing issues, you probably should not be performing hazardous tasks.

RULE 5: TELL ME AGAIN

THIS ENERGIZED?

Turn it off!! That is the best way to eliminate the hazards.

SUMMARY

Understanding the application, and more importantly the limitations, of your PPE is vital if you are to go through the work day properly protected from the hazards of electricity. So please take the time to read and understand the definitions, the application, and the limitations of your PPE.

Hey that Rule No. 5 – you might want to move that one up to the top of the list.

Ron Widup and Jim White

Requirements for Employee Workplaces). Both gentlemen are employees of Shermco Industries in Dallas, Texas a NETA Accredited Company. Ron Widup is President of is a Principal member of the Technical Committee on

committee “Recommended Practice for Electrical Equipment

White is nationally recognized for technical skills and safety training in the electrical power systems industry. He is the Training Director for Shermco Industries, and has spent safety training for electrical power system technicians. Jim

Equipment for Workers”.

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NETA and our NETA Accredited Companies invite YOU to become a part of NETA’s technical community and take advantage of the many benefits of becoming a NETA Gold or Standard Affiliate.

As a NETA Affiliate you can participate in NETA’s Technical Working Committee, qualify for substantial discounts, and access industry leading experts and technical resources. Call or go online to

Electrical Distribution System

BATTERYM BATTERY M AINTENAN C E R EC OMMEN DATIONS FOR UPS SYSTEMS

BY LYNN HAMRICK, Shermco Industries

The battery is by far the most vulnerable and failure-prone is allocated to maximizing a battery’s reliability and life. To appropriately maintain a battery system, one must first understand the chemistry associated with the UPS’s battery system.

BATTERY CHEMISTRY

A flooded, lead-acid battery is typically used for larger UPS systems. For a lead-acid battery, lead oxide (PbO ) is the active material in the positive electrode and lead (Pb) is the active material in the negative electrode. The basic electrochemical reaction equation for a lead-acid battery is as follows:

Pb + 2H SO + PbO < > 2PbSO + 2H O + energy

The electrolyte in the battery is the sulfuric acid (H SO ) and the water (H O) associated with the chemical reaction. The direction of the reaction is dependent on whether the battery is charging or discharging. In a discharging battery, the lead oxide and lead react with the sulfuric acid to create lead sulfate (PbSO ), water, and energy. When the battery is being charged, the cycle is reversed with energy being added (charging) and the lead sulfate and water electrochemically reacting to form lead and lead dioxide.

Lead oxide, the active material in the positive electrode, is in the same family as rust (FeO2), which is considered a corrosive molecule. When charging a lead acid battery, the reaction is reforming the corrosive layer of the positive electrode which is necessary for optimal battery performance. To properly corrode the positive electrode, the battery voltage has to reach and then slightly exceed the gassing potential of the battery. When a battery is charging, the electrolytic breakdown of the water in the electrolyte produces oxygen on the positive plates and hydrogen on the negative plates. This is normal. However, if a high charging rate is continued after the battery has been brought to its gassing voltage, the gassing becomes excessive, and abnormally larger amounts of hydrogen and oxygen gases are produced. The best indication of excessive gassing is a very noticeable bubbling action of the electrolyte and high electrolyte temperature. Some gassing in the electrolyte is beneficial since it acts to stir the liquid. Without

gassing, a process called electrolyte stratification can occur, where the heavier electrolyte sinks to the bottom of the cell. In the electrolyte, the sulfuric acid is heavier than water so the acid will sink and concentrate at the bottom of the battery. Therefore, an inadequate charging environment will result in ineffective corrosion of the positive plate and inadequate gassing which will lead to electrolyte stratification and reduced performance and shortened life of the battery.

In a new battery, the electrochemical reaction occurs efficiently. Unfortunately, as a battery ages a process called sulfation occurs. Sulfation is the process where the lead and sulfates bond and form crystals. In a crystalline form, more energy is required to break the bond; the longer the crystal lasts and grows, the more difficult this bond is to break. These growing crystals of lead sulfate are insoluble. The formation of these crystals can cause the plate material to warp which can cause the case to bulge, or to push adjacent plates together. Further, electrolyte stratification can result in the lower portion of the plates becoming inactive, which enhances the sulfation process. Undercharging a battery, even to a small degree, can lead to excessive sulfation. The same is true of batteries which have been left standing in an undercharged state for an extended period. High temperatures rapidly accelerate sulfation when batteries are left standing in a partially charged condition. The cells of a sulfated battery will have low specific gravity and open circuit voltage readings. On charge, voltage readings will be unusually high. The battery will not become fully charged after a normal charging cycle when sulfation has taken place over a prolonged period.

A new battery should be checked every few weeks to determine the watering requirement. This prevents the electrolyte from falling below the plates. Avoid exposed plates at all times, as this will cause damage leading to reduced capacity and lower performance. Additionally, with regard to gassing, hydrogen is a highly combustible gas and will explode on ignition when the concentration in air reaches a level between four percent and 74 percent. (Below 4% the concentration is too weak; above 74% there is not enough oxygen left in the air to support combustion.) Therefore, if excessive gassing exists, troubleshooting of the battery and charging equipment should be performed. An unusually high usage of water indicates that excessive gassing is occurring.

Battery charging is probably the second most important factor in maintaining a battery system. A properly functioning battery charging system, with a healthy battery condition, will result in a fully charged and reliable battery system that is available when called upon for service. The following checks are a quick way of determining a proper and fully charged battery.

BATTERY MAINTENANCE

To maximize battery life, appropriate battery maintenance must be based on the simple chemistry lesson presented above.

Watering is the single most important factor in maintaining a flooded lead-acid battery. The frequency of watering depends on usage, charge method, and operating temperature.

Watering

is the single most important factor in maintaining a flooded lead-acid battery. The frequency of watering depends on usage, charge method, and operating temperature.

FEATURE

An excessive amount of charge results in high battery temperature and a reduced battery service life. To obtain maximum service life from a battery, it should be charged and operated within temperature ranges recommended by the manufacturer. Overheating can damage the battery and shorten its normal expected service life. The extent of the damage and service life loss depends on the magnitude of the temperature, how often the overheating occurs, and how long the batteries are subjected to high temperatures. A healthy battery charged on a properly functioning charger will have a 10 to 20° F rise in temperature when fully charged. This temperature rise is affected by several variable factors: temperature

thermographic surveys should be performed on battery systems on at least an annual basis. The preventive maintenance program for the battery systems should also include the following:

VISUAL INSPECTION OF BATTERY CELLS

Batteries should be visually inspected under normal float conditions.

Inspect the Electrolyte Level. Flooded cells have translucent or transparent jars, so the electrolyte level can easily be compared to a recommended level that is marked on the cells.

At a minimum, annual testing, verification, and inspection of a battery system should be performed. Additional quarterly or semiannual inspections should be performed if the age and condition of the battery warrant the activity and it is determined that the battery system is critical to the reliability of the associated power system. As with all electrical systems, infrared

At a minimum, annual testing, verification, and inspection of a battery system should be performed.

Inspect the Positive Plates. The positive plates are typically the first to wear out and are located toward the center of the jar. They should be dark brown or black. Sparkle is evidence of sulfation or undercharge. Look for cracks, breaks, and pieces hanging on the side. This is indicative that the cell should be replaced and that other cells may also have a similar problem.

Inspect the Negative Plates. The negative plates are thinner than the positive plates and sit toward the outside of the jar. These should have a clean lead color from top to bottom. Pink discoloration indicates copper contamination.

Look at the Sediment. Inspection of the sediment should provide a general idea of the battery condition as trended from the last inspection. Accumulation of gray material under the negative plates accompanied by sparse black sediment is indicative of an undercharging condition. Excess black sediment under the positive plates with little negative sediment is indicative of an overcharging condition or excess temperature. If excess sediment covers the bottom of the jar, the battery has been cycled heavily or operated at high temperature.

A crusty trail or accumulation is evidence of electrolyte leakage. Signs of corrosion on the terminal connections, intercell connections, and racks are also indicative of electrolyte leakage.

flame arrestersable and that suitable eyewash equipment is present.

VERIFY BATTERY CHARGING PERFORMANCE

There is more to verifying battery charging performance than just recording the voltage levels.

Voltage. The cell voltage value should be in accordance with manufacturer’s published data. Low cell voltage is indicative of a problem with the cell.

under close observation for unusual heat rise and excessive venting. Some venting is normal and the hydrogen emitted is highly flammable.

Temperature. Specific gravity is useful in evaluating charger float voltage as well as cell internal health. For most UPSrelated battery systems, a specific gravity of 1.250 is typical for each cell. If the specific gravity drops by .015 to .020 from this value, it is usually indicative of inadequate charger float voltage or a problem with a cell holding a charge. Remember, specific gravity should always be adjusted for internal cell temperature differences from 25 degrees C at a rate of .001 for every 1.67 degrees C difference. Also, electrolyte levels should be taken into consideration when evaluating specific gravity. Cells with low electrolyte levels typically need water added and, therefore, will have a higher specific gravity.

Equalizing Voltage Levels. Charger float voltage is the typical voltage output for a normal charging process. This voltage should be in accordance with the manufacturer’s recommendations, but may need to be increased as the battery ages or degrades. An equalizing charge is nothing more than forced overcharge. Applying an equalizing charge periodically brings all cells to similar levels by increasing the voltage to ~10 percent higher than the recommended float voltage. This process removes sulfation that may have formed during low-charge conditions. One method of evaluating sulfation is to compare the specific gravity readings on the individual cells of a flooded lead-acid battery. Only apply equalization if the specific gravity difference between the cells is 0.030. During an equalizing charge, check the changes in the specific gravity reading every hour and discontinue the charge when the specific gravity no longer rises. This is the time when no further improvement is possible, and a continued charge would cause damage. The battery must be kept cool and

CLEANING BATTERY POSTS AND CONNECTIONS

Before cleaning, note the condition of posts and connectors. Except for a light coating of grease, these should look new. Consider the following colors:

This is lead peroxide, indicating an acid leak around the positive post.

This is corroded copper, indicating connectors need cleaning and close inspection — they may no longer be serviceable.

White- This is lead hydrate, indicating a leak around the negative post.

The jars’ surfaces can be cleaned any time, but cleaning connectors and posts requires opening the battery circuit. If the cleaning requires that the battery be taken out of service without a parallel system, the UPS will not respond to a power loss. Therefore, cleaning should be coordinated with the operator. This following cleaning procedure should be performed when required.

connectors, and then neutralize them with a suitable solution like baking soda and water.

until clean lead is exposed. Do not clean too vigorously or with a wire brush because it may remove too much lead.

Neutralize with suitable solution. Replace corroded hardware. Replace lockwashers, regardless of condition. Use only leadplated or 316-stainless steel bolts, washers, and nuts.

connectors with a light layer of antioxidant grease approved for battery use.

away from the connector. If possible, install lockwashers on the nut side, not the bolt side.

specifications. Turn the nut, not the bolt, if possible.

microhmmeter. If resistance is high, check the torque; overtorquing degrades the connection. If the torque is correct but the value is high, disassemble and inspect contact surfaces for proper polishing.

PERIODIC ELECTRICAL TESTING

In addition to the periodic visual inspections and battery system checks discussed above, specific electrical tests should be performed. IEEE Standard 450 details the recommended testing and maintenance for large stationary, wet batteries. As stated in IEEE Standard 450, the practices recommended in these standards “serve as a valuable aid in maximizing battery life, preventing avoidable failures, and reducing premature replacement.” The addition of an occasional load test of the battery system should be considered as the battery system ages or other problems are identified.

The battery is by far the most vulnerable and failure-prone part of a UPS system. battery’s reliability and life.

In support of this recommendation for load testing, some other more sophisticated testing methods can and should be performed more regularly to accurately determine battery health. These methods measure the internal ohmic values of the battery or associated cells.

Ohmic measurement using dc voltage is one of the oldest and most reliable test methods for battery systems. An instrument applies a load to a cell or a small string of cells lasting a few seconds. The load current typically ranges from 25-70 amperes, depending on battery size. The drop in voltage divided by the input current provides an accurate and repeatable resistance value. Alber’s CRT-300 Cellcorder is an example of this type of instrument. A cell’s internal resistance provides useful information in detecting problems and can be used for

indicating when a battery or battery cell should be replaced. However, resistance alone does not provide a linear correlation to the battery's capacity. The increase of cell resistance only relates to aging and provides some failure indications. Rather than relying on an absolute resistance reading, service technicians take a snapshot of the cell resistances when the battery is installed and then measure the subtle changes as the cells age. An increase in resistance of 25 percent over an initial baseline (100%) or related cells indicates a performance drop to about 80 percent.

Ohmic measurement using ac voltage is also a generally accepted test method for battery systems. An instrument applies an ac signal into a cell or small string of cells at a known frequency between 80-100 hertz. From this signal the conductance is derived in terms of mhos, or Siemens. A major benefit to using conductance is the ability to calculate a battery's capacity without performing an extensive discharge or load test. Midtronic’s Celltron CTM-300 is an example of this type of instrument. A battery's measured conductance correlates linearly with its ability to deliver current. As conductance declines, so does a battery's ability to meet its specified capacity and supply energy. A decrease in conductance of 25 percent over an initial baseline (100%) or related cells indicates a performance drop to about 80 percent.

In summary, the battery is by far the most vulnerable and failure-prone part of a UPS system. Because of this, much time and effort is allocated to maximizing a battery’s

reliability requirements, battery systems should be inspected and tested on a regular frequency to maximize battery life, prevent avoidable failures, and reduce premature battery replacement.

reliability and life. To appropriately maintain a battery system, one must first understand the chemistry associated with the UPS’s battery system. Based on the battery chemistry and the criticality of the system, a very specific preventive maintenance program should be implemented. Based on this criticality and associated reliability requirements, battery systems should be inspected and tested on a regular frequency to maximize battery life, prevent avoidable failures, and reduce premature battery replacement.

Lynn Hamrick years of working knowledge in design, permitting, construction, and startup of mechanical, electrical, and instrumentation and controls projects as well as experience in the operation and maintenance of facilities.

Lynn is a Professional Engineer, Certified Energy Manager and has a BS in Nuclear

Midtronic Celltron

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BYWILLKNAPEK BY WILL KNAPEK , OMICRON Electronics Corp USA

LINE IMPEDANCE TESTING

Between 80-90 percent of all power system faults involve ground. Many protective relaying schemes depend on ground distance protection to accurately sense and locate ground faults on multiterminal subtransmission and transmission lines. In addition to the need for dependable ground fault detection, protective relaying must provide adequate selectivity to avoid ovetripping for faults outside of its zone of protection and other undesired consequences, such as undertripping or unintended automatic reclosing initiation.

The problem has become more apparent due to recent major power system disturbances in North America such as the Northeast blackout of 2003. Correct application and setting of protective devices, particularly distance relays, have become subject to heavy scrutiny lately. Validation of accurate distance relay settings is now a major topic of discussion by electric power utilities as well as professional technical committees such as the IEEE Power Systems Relaying Committee. It becomes apparent very quickly that the accuracy of line parameter values may affect many people.

Although ground distance relay design, characteristics, and implementations vary, some of the typical parameters required to set a ground distance relay include the following:

characteristic angle and angles

coupling compensation)

Relay manufacturers have different methods of calculating zero-sequence compensation, also known as the k factor, but generally it is defined

SOLVING RELAY MISOPERATIONS

as the ratio between the zero-sequence imped-

k factor is used to correct the ground impedance calculation so that the ground fault loop calculation can be simplified and treated similarly to the phaseto-phase fault loop calculations performed in the protective device. Therefore, if the k factor is not accurate, fault reach (distance) will be calculated incorrectly. Transmission line impedances used for k factor are often calculated by line constants programs. Due to the large number of variables required, line parameter calculations are prone to error, particularly in the zero-sequence impedance value of the line. For example, utilities often assume fixed soil resistivity values (10 Ωm, 100 Ωm, etc.) applied across their system models, even in cases where the transmission line may span types of soils different from those assumed in the line constants program. Due to the uncertainties related to soil resistivity and actual transmission tower grounding, the calcu-

ance. For parallel transmission lines, the accurate calculation of zero-sequence mutual impedance

Figure 1:

SOLVING RELAY MISOPERATIONS

Such errors in the estimation and calculation of line parameters will affect accuracy of settings used in transmission line protective devices, particularly in distance and overcurrent relays, causing them to either underreach or overreach, resulting in a misoperation. In order words, relay sensitivity to detect ground faults will be affected.

many digital relays to calculate the location from the line terminal to the fault. Accurate fault location data is needed by utility crews to promptly locate and remove foreign objects from the primary system, and repair damaged lines as quickly as possible. Moreover, short-circuit and coordination studies also depend on accurate modeling data to enable the protection engineer to set relays correctly.

The alternative to line parameter calculation is taking actual measurements on a given transmission line to accurately determine its impedances and k factor. Measuring the line impedance using the correct techniques,

equipment, and safety precautions provides the opportunity to eliminate the uncertainties described above. In the past, line parameter measurement was considered prohibitive and costly as it required large, high-power equipment to overcome nominal frequency interferences, since off-nominal frequency injection was not possible. With modern digital technology and ingenious design, OMICRON has overcome these challenges with the CP CU1 coupling unit, an extension to the CPC 100 (Figure 1).

Will Knapek is an Application Engineer for OMICRON electronics Corp, USA. He holds a BS from East Carolina University and an AS from Western Kentucky University, both in Industrial Technology. He retired from the US Army as a Chief Warrant Officer after 20 years of service, 15 of which were in the power field. Will Knapek has been active in the testing field since 1995 and is certified as a Senior NICET Technician and a former NETA Certified Test Technician,Level IV. Will is also a member of IEEE.

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PART1

DATA CENTER MAINTENANCE THE ELECTRICAL MAINTENANCE PROGRAM

THIS ARTICLE IS PART 1 OF A 4-PART SERIES ON DATA CENTER MAINTENANCE.

BY LYNN HAMRICK, Shermco Industries

Data center maintenance was a topic of discussion at the 7x24 Exchange Fall Conference held in Phoenix in November 2011. The keynote speaker was Steve Fairfax, President of MTechnology, whose company had recently conducted an indepth analysis of failure rates in data centers. Mr. Fairfax made the following comments during his key note address: “There’s this mantra that more maintenance equals more reliability. We get the perception that lots of testing improves component reliability. It does not. The most common threat to reliability is excessive maintenance.” He went on to say, “The purpose (of maintenance) should be to find defects and remove them, but maintenance can introduce new defects. And whenever a piece of equipment is undergoing maintenance, your data center is less reliable.” He also added, “Maintenance is a very lucrative business,” and stated that equipment vendors sometimes slip into FUD (fear, uncertainty, doubt) rather than sound methodology. “They want to keep selling their maintenance plans. To overcome this preventive maintenance threat, we must attack false learning. More is not always better.” 1

These statements border on blasphemy for maintenance professionals. Unfortunately, excessive maintenance can be expensive and can make a data center less reliable. There are some factors that would contribute to this unfortunate situation. Improperly maintained documentation, poor maintenance planning and procedures, and unqualified maintenance personnel are at the front of the list. For data centers, maintenance plans are typically broken down into three categories, each with its own set of challenges: computer systems, cooling systems, and electrical infrastructure systems. This article will focus on the key attributes of an effective electrical maintenance program.

With regard to electrical infrastructure, data centers are unique, when compared to other commercial facilities and industrial facilities. Data centers consist of the power distribution system (i.e., transformers, breakers, and conductors), uninterruptible power supplies (UPSs) with battery systems, and backup generator systems. Basically, everything within the electrical infrastructure is critical to the facility’s reliable operation and should be properly maintained. However, from a maintenance planning standpoint, performing appropriate maintenance is a nightmare because of the inherent reduced reliability when components and systems are taken out of service.

Through the application of Best Practices and with the use of sound technical expertise, a maintenance program can be achieved which can result in significant reductions in maintenance costs and savings associated with unplanned outages and equipment failures. To achieve these cost benefits, there are some basic concepts which should be considered:

CORPORATE PHILOSOPHY

Unlike many industrial and commercial facilities, data centers have a corporate culture which is committed to a best practices electrical maintenance program. The problem with implementation becomes a matter of appropriate planning and cost control.

ASSET MANAGEMENT

For optimal electrical maintenance, the data center’s electrical infrastructure should be organized into asset centers and treated as individual cost centers with all costs, equipment, personnel, and material tracked and monitored to allow for accurate cost identification and control. It is essential that required maintenance parts be on hand and adequate to meet the needs of all work in progress as well as emergencies. A process for maintaining and controlling spare parts inventories is essential to a cost effective maintenance program. Therefore, purchasing also plays an important role in the modern, integrated maintenance organization. The use of an automated system to trigger purchase orders that are designed to facilitate stocking levels as they are established is preferred. Adequate planning and proper establishment of workable stock levels (controlled by supply lead-time and usage) can prevent stock outages and overstocking.

MAINTENANCE PLANNING

With assets and parts identified, corrective and preventive maintenance can be carried out in a more meaningful fashion. Personnel can be assigned to meet the needs of the newly created asset centers with their costs directly associated to the individual asset center. A work order system should be established which communicates what is being done, by whom, where, when, and why. Written procedures for the work order process should be developed and strictly adhered to. Detailed responsibilities are assigned to specific personnel for the completion and reporting of work. Planning is the critical stage in the work order system so that expected labor, material, and time-line requirements for maintenance are accurately estimated and scheduled to meet the data center’s maintenance needs. Additionally, the planning process should ensure that cost and

NICHE MARKET TESTING

scope of work is adequately tracked. For electrical maintenance, NFPA 70B, Recommended Practice for Electrical Equipment Maintenance, and ANSI/ NETA MTS, Maintenance Testing Specifications, are extremely useful references in performing the electrical maintenance planning function. Specifically, use of ANSI/NETA MTS, Appendix B, Frequency of Maintenance Tests, is invaluable in planning electrical maintenance activities.

PM programs typically include some componentsof predictive maintenance as well as inspection activities by data center personnel. They also include some PM activities that can be invasive to operation and, therefore, are performed during scheduled outages when equipment is deenergized. Cleaning, inspecting, and lubricating electrical equipment, along with periodic perfor

NICHE MARKET TESTING

mance and integrity testing, are essential to an effective electrical PM program. The key to a successful PM program is performance and should be limited to activities which are deemed necessary to meet the objective: To reduce downtime and maintain safety to a level that is acceptable and manageable. Implicit in this description is that an effective PM program is sufficient but not excessive. It requires that an evaluation of equipment and systems be performed so that equipment, which is critical to reliable operation and/ or employee safety, receives the bulk of the attention. Obvious in this statement is that the people performing this evaluation are knowledgeable of the equipment and qualified and experienced in recognizing potential problems.

NFPA 70B Recommended Practice for Electrical Equipment Maintenance 2010 Edition

Any effective PM program includes some components of predictive maintenance. PdM activities are typically noninvasive and are performed while equipment is operating. Through proper application of the many and varied predictive maintenance tools, potential failure modes can be identified and used to effectively predict eventual failure with some degree of accuracy over time. This predictive capability allows for more effective maintenance planning and improved equipment availability. The more common predictive tools that should be performed include walkthrough inspections, insulating fluid sample analysis, and infrared thermographic (IR) surveys. Additionally, ultrasonic surveys and partial discharge testing should be considered when higher voltage (>1000 V) applications are included.

Proactive maintenance is a term used to identify the enhancement of both the preventive and predictive maintenance technologies through the use of operating and maintenance history. Asset centers are evaluated for uptime versus downtime, with written failure analyses provided for unscheduled downtime. These failure analyses are then used for refining the preventive and predictive processes, activities, and schedules. Methodologies for determining and then modifying recommended maintenance frequencies based on operating and maintenance history are discussed in both NFPA 70B and ANSI/NETA MTS. Proactive maintenance should provide managers with a vehicle to effectively reduce total maintenance costs while maximizing equipment production reliability and useful life.

PERFORMANCE MEASUREMENT

Accountability is required and must be built into the system. Activities need to be evaluated through key indicators of reliability and equipment condition and tracked over time for improvement measurement. The indicators are then used to highlight the success of the plan and serve to reinforce any actions taken. To reinforce the benefits of the overall electrical maintenance program, consideration should be given to documenting and reporting the success of the program by photographing examples of suspect equipment condition.

This photographic evidence of electrical issues can then be reported to management to demonstrate the effectiveness of the program and provide a basis for training personnel in visual recognition for future inspections. Also, to ensure that indicators are intelligently and expeditiously acted upon, a process which tracks and reports progress against the objectives should be implemented. A complementary review team of maintenance and supervisory personnel should be used to review and evaluate the results of electrical equipment performance and integrity testing as well as the impact on manufacturing reliability indicators.

CONTINUOUS IMPROVEMENT

This concept of continuous improvement in electrical maintenance activities integrates preventive, predictive, and proactive maintenance with accountability for each asset center. The key to these maintenance activities being successful is the unified focus of improved performance, productivity, and reliability. This means that the facility has committed to superior work planning and execution, performance measurement and tracking, maintenance cost control, and failure analysis with corrective action.

The above best practices provide the key elements associated with an effective conditionbased maintenance program. However, there are at least two factors that should be discussed further because of their impact to the program: accurate documentation and qualified personnel. A data center could have adequate processes

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and procedures in place, but without accurate documentation and qualified workers the program would be doomed to failure as the speaker has noted with his research.

To achieve an effective electrical maintenance program for a data center, a management commitment which is communicated and accepted by a qualified workforce is required. The electrical maintenance practices should include significant planning and scheduling emphasis. The requirements for spare parts inventory and the type of maintenance activities to be performed should be minimized, yet sufficient to meet the objectives of the program. Maintenance best practices should include components of asset management, preventive maintenance, predictive maintenance, and proactive maintenance. Finally, the program should include attributes of continuous improvement and a process for performance measurement and tracking.

Lynn Hamrick years of working knowledge in design, permitting, construction, and startup of mechanical, electrical, and instrumentation and controls projects as well as experience in the operation and maintenance of facilities.

Lynn is a Professional Engineer, Certified Energy Manager and has a BS in Nuclear Engineering

1 http://www.datacenterknowledge.com,“Is Maintenance Making Your Facility Less Reliable?” by Rich Miller, dated November 17, 2011.

TESTING ROTATING MACHINERY

CSA

BY VICKI WARREN AND IAN CULBERT, Iris Power LP.

SQUIRREL-CAGE ROTOR COMPONENTS

The vast majority of rotors in ac induction motors are squirrel-cage designs becaus e they are durable and economical. The rotor is made of laminated steel punching (core iron), rotor bars, shorting rings and a shaft. The winding is embedded in slots near the outer surface of the rotor. For larger motors, the winding bars are made from of uninsulated copper, copper alloy, aluminum alloy, or other suitable material embedded in the slots of the rotor punchings. The rotor bars are extended beyond the ends of the rotor core connected together by shorting rings (end rings) to provide closed-loop current paths (Figure 1). Lower

horsepower motors often have die cast aluminum alloy rotor windings because of their economical advantage, whereas others are normally fabricated.

Figure 1: Rotor Layout

TESTING ROTATING MACHINERY

FAILURE MECHANISMS

Depending on the specific application and design, each motor has its own limitations. Motors with high inertia loads are more apt to develop winding problems because of long accelerating time with high starting currents. This is especially true if they have fabricated aluminum alloy rotor windings that have poor mechanical properties at high temperatures.

Excessive Starts

During direct on-line starting, a squirrel-cage induction motor will draw anywhere from five to eight times the normal rated current required to run under full-load conditions. Most all of the energy that normally goes to torque occurs as heat, which quickly raises the rotor winding temperature. It takes time to dissipate this heat once the motor is up to speed. When the motor is turned off there is less cooling, and if it is restarted before the rotor has cooled, additional heat is added. This causes escalating temperature leading to melting, particularly in die-cast aluminum windings.

damage of a broken cage winding are strikes on the stator winding from pieces of broken bar or shorting ring, broken bar ends rising out of slot to strike the stator winding, and high vibration levels causing bearing damage. In addition, when rotor bars break, the rotor current going between bars takes the lowest path of resistance, which is through the rotor core. This causes burning of the core laminations.

Manufacturing Issues

Poor process control allows large air voids to occur within the cast aluminum bars or shorting ring. This leads to high local resistance at void sites causing local heating that may melt aluminum or cause unsymmetrical magnetic fields (and vibration). These can make the rotor behave as if it had broken bars or shorting rings with high vibration levels that may vary with load.

During starting, most of the current in rotor bars flows near the air gap, due to skin effect. The top of the bar has higher current and thus higher temperature, leading to the top of the bar expanding more than the bottom of the bar. Continuous and cyclic centrifugal forces from starts and stops cause cracking of braze between bars and short-circuit ring (Figure 2), cracking of bars in the extensions beyond the core, or cracking of the short-circuit ring. Although broken rotor bars do not initially cause an induction motor to fail, there can be serious secondary effects. The consequential

If all the bars are loose, the whole rotor cage winding may move axially in one direction. This may cause rotor vibration levels to increase due to unbalance or broken rotor bars at the end where the bar extensions beyond the core become shorter. If only some bars are loose then rotor vibration levels will increase due to nonuniform bar expansion under load which creates rotor bending, cracking, unbalance, and high vibration levels which vary with load. For fabricated windings, if bars are undersized or not swaged, they will become loose in the slots.

Endwinding Support

The short-circuit ring may not be mechanically strong enough to withstand centrifugal and thermal forces, or have inadequate end winding retaining ring support

It is now accepted by industry that Current Signature Analysis (CSA) is the most applicable and effective test for the diagnosis of broken rotor bars in three-phase induction motor drives.1-2 Analysis of stator current with special Fast Fourier Transform Analysis technique can yield side band harmonic information to show presence of cracked or broken rotor bars in squirrel-cage windings and air pockets in die cast aluminum windings.3 A CSA system for detecting these specific problems must also include features to detect current components from purely mechanical phenomena in the drive system to ensure a reliable diagnosis. 4-7

Figure 2: Cracking of Braze Between Bars and Short-Circuit Ring

TESTING ROTATING MACHINERY

Rotor problems that can be detected by CSA are as follows:

between the two

fs = (1 ± 2s) f1

n = 2R

10 N/20 + p

f1: supply frequency

R: no. of rotor slots

p: no. of pole pairs sb

The rotor currents in a cage winding produce an effective three-phase symmetrical, forward-rotating, magnetic field, which has the same number of poles as the stator field but is rotating at slip frequency with respect to the rotating rotor. If rotor current asymmetry occurs, there will be a resultant backward (i.e. ,slower) rotating field at slip frequency with respect to the forward rotating rotor. Asymmetry results if there are one or more breaks in the rotor cage winding, preventing current from flowing through the one or more slots. With respect to the stationary stator winding, this backward rotating field at slip frequency with respect to the rotor (as well as the resulting torque oscillation) induces currents in the stator winding at power frequency + 2* slip frequency: fsb = f1(1±2s).

In general, the difference between the current magnitude at f1 (line frequency) and the sidebands fsb (± [2* slip frequency]) separate from f1 should be greater than 45 dB for a rotor cage winding in good condition. A difference less than this is often the sign of one or more broken rotor bars, a shorting ring, or joints between them. The smaller the dB difference, between f1 and fsb, the higher the probability for more than one broken rotor bar. This difference can be trended to detect increasing numbers of broken bars in a squirrel-cage rotor winding.

CSA detects these sidebands by measuring the stator current on one phase with a current transformer (Figure 3). A highresolution spectrum analyzer is used to detect sidebands about 1 Hz above and below power frequency (Figure 4).

The ‘trick’ is to accurately measure slip speed, even if load is oscillating since the mechanical load and drive train characteristics can often cause speed oscillations that also induce current sidebands in the same region as broken rotor bars.

If the identified sideband is due to broken bars an estimate of the number of breaks can be obtained if the number of rotor slots is known. Broken bars are present if the sideband is more than 1/200th the power frequency current – so magnitudes in dB.

There are two types of air gap eccentricity, namely static and dynamic. Static eccentricity (Se) is when the minimum air gap is stationary relative to the stator, whereas dynamic eccentricity (de) occurs when the minimum air gap rotates with rotor. Manufacturers keep dynamic eccentricity at as small a level as possible; otherwise, high levels of vibration will occur at the bearings. Because static eccentricity leads to shaft bending from unbalanced magnetic pull (UMP) it is virtually impossible to have static eccentricity without some dynamic eccentricity. 8 An increase in air gap eccentricity increases the electromagnetic forces acting between the stator and rotar and may lead to mechanical damage of the stator insulation if the rotor pulls over to rub the stator bore.

Air gap eccentricity (AGE) can be caused by

during motor assembly

the stator bore

from UMP

Figure 3: CT and Spectrum Analyser

Figure 4: CSA Theory

Case Study 1:Healthy Motor

Figure 5: Healthy Motor

Case Study 2: Broken Rotor Bars

TESTING ROTATING MACHINERY

Figure 6: Broken Rotor Bars

Case Study 3: Influence of Gear Box

Gearboxes with slow output speeds can give rise to fundamental current components, or harmonics thereof, in the frequency range in which broken bar components may be found: [f1(1-2s ) to f1(1+2s )]. Thus, to avoid false indications of broken rotor bars, it is essential that gearbox

Figure 7: Gear Box Influence

Vibration analysis indicated a possible broken rotor bar problem. The motor was tested with high resolution (10 mHz/line) instrument and there was no evidence of cage breaks; thus broken rotor bars were eliminated as the possible cause (Figure 5).

CSA indicated 2sf1 sidebands ≈ 38 dB down from the fundamental 60 Hz current component indicating broken bars (Figure 6). Using the formula opposite Figure 3, 3.8 broken bars were estimated, and when the motor was disassembled four broken bars were found.

wear be considered when investigating for broken rotor bars. If current components due to shafts rotating with Nr rpm are: fm = f1 ± mfr (where fr = Nr/60 and m= or a constant depending on the gear-box ratio), they may be mistaken for broken rotor bars.

Two fundamental frequency components of this shaft speed are distributed ± 0.35 Hz from f1. The fourth harmonic of this output shaft rotational speed (± 1.4 Hz) is within the broken bar frequency range (Figure 7). If gear box had not been defined broken bars would have been falsely indicated

TESTING ROTATING MACHINERY

Figure 8: Frequency of Static Eccentricity

The specific frequencies of the current components indicative of air gap eccentricity, fec , may be calculated by

Where;

fec = static air gap frequency

f1 = supply frequency

R = number of rotor slots

rotor sli

p = pole-pairs

nws integer

The AGE formula equates to a series of slot passing frequency components that are twice power supply frequency (Figure 8) apart (±2f1) and have sidebands that are ± rotational speed frequency (fr).

r = rotor slot passing frequency

Based on the difference between e and the average of e1 and e2

avg. = [Se e e2)]

Case

Study 5: Air-gap Eccentricity

Figure 9: Case Study - AGE

The smaller the the greater is the air gap eccentricity.

rotor slots

High 1X rpm vibration

CSA for air gap eccentricity gave highest ƒe e and sidebands Lower ƒr sideband and upper ƒr side band

avg. = [Se e e2)]

This value indicates above normal AGE.

TESTING ROTATING MACHINERY

Shaft Misalignment

Shaft misalignment causes changes in air-gap eccentricity that generate current components with frequencies fim

Where ƒ 1 = the supply current frequency m the mechanical problem

ƒ r = rotor rotational speed frequency

CONCLUSIONS

Vicki Warren, Senior Product Engineer, Iris Power

LP. Vicki is an electrical engineer with extensive experience in testing and maintenance of motor and generator windings. Prior to joining Iris in 1996, she worked for the U.S. Army Corps of Engineers for 13 years. While with the Corps, she was responsible for the testing and maintenance of hydrogenerator windings, switchgear, transformers, protection and control devices, development of SCADA software, and the installation of local area networks. At Iris, Vicki has been involved in using partial discharge testing to evaluate the condition of insulation systems used in medium- to high-voltage rotating machines, switchgear and transformers. Additionally, she has worked extensively in the development and design of new products used for condition monitoring of insulation systems, both periodical and continual. Vicki also actively participated in the development of multiple IEEE standards and guides and was Chair of the IEEE 43-2000 Working Group.

1 IEEE: Motor Reliability Working Group, “Report of Large Motor Reliability Survey of Industrial Commercial Installations”, Part I, Transactions on Industry Applications, Vol. 1A-21, No 4, July/August, 1985, Parts I and II, pp 853-872.

2 EPRI: “Improved Motors for Utility Applications and Improved Motors for Utility Applications, Industry Assessment Study”, Vol. 1, EPRI EL-2678, Vol. 1 1763-1, final report and EPRI EL-2678, Vol. 2, 1763-1 final report October 1982.

3 W. T. Thomson: “A Review of On -Line Condition Monitoring Techniques for Three Phase Squirrel Cage Induction Motors - Past, Present and Future”, Proc. IEEE International Syposium (keynote address) on Diagnostics for Electrical Machines, Power Electronics and Drives, Spain, ISBN: 844-699-0977-0 , 1999, pp 3-18.

4 W. T. Thomson: “On-line Current Monitoring – The Influence of Mechanical Loads/Unique Rotor Designs on the Detection of Broken Rotor Bars in SCIMs”, ICEM’92 UMIST, Manchester, UK, 1992.

Case studies clearly demonstrate that CSA can be a reliable diagnostic technique for monitoring the health of rotors and the diagnosis of abnormal levels of air-gap eccentricity in three-phase induction motors. An essential ingredient of the diagnostic strategy is also the inclusion of such factors as mechanical load/drive train characteristics, operational condition at the time of diagnosis, rotor design, duty cycle, rating of the motor, etc. Existing CSA systems tend to use a combination of a front-end signal conditioner, a spectrum analyser and a computer. New technology provides for continuous CSA monitoring to provide maintenance personnel advanced notice should a problem develop. In combination with partial discharge monitoring for assessing the health of stator windings 9 means that a unified condition monitoring strategy is now available for induction motor drives.

Ian Culbert has been a Rotating Machines Specialist at Iris Power L.P since April 2002. Before joining Iris Power he was a motor and small generator specialist with Ontario Hydro/Ontario Power Generation from 1977 to 2002 and prior to then a motor designer with Parsons Peebles, Scotland, and Reliance Electric, Canada. Ian is a Registered Professional Engineer in the Province of Ontario, Canada, and a Senior Member of IEEE. He has co-authored two books on electrical machine insulation design, evaluation, aging, testing and repair and been principal author of a number of Electric Power Research Institute reports on motor repair. Ian has also coauthored a number of papers on motor electrical component on-line and offline motor diagnostics testing.

5 R. C. Kryter and H. D. Haynes: “Condition Monitoring of Machinery using Motor Current Signature Analysis”, Sound and Vibration, 23(9), 14, 1989, pp 14-21.

6 W. T. Thomson and C. Campbell: “Current Monitoring for Detecting Broken Rotor Bars - The Influence of a Gearbox in the Drive”, UPEC Proc, UK, 1991.

7 W. T. Thomson: “On-line Current Monitoring to Diagnose Shaft Misalignment in 3-phase Induction Motor Drive Systems”, Proc ICEM’94, Paris, 1994, pp 238-243.

8 J.R. Cameron, W. T. Thomson and A. B. Dow: “Vibration and Current Monitoring for Detecting Airgap Eccentricity in Large Induction Motors”, Proc IEE Journal, Part B, Vol. 133, No 3, May 1986.

9 G.C. Stone, S.R. Campbell and H.G. Sedding: “Application of PD Testing of 4kV, Motor and Generator Stator Windings”, Proceedings IEEE Electrical Insulation Conference, Sept.1995.

Everything on the line

Event Highlights

WHY

SERVICEABLE BATTERIES?

BY KLAS BJÖRCK, Megger

Storage batteries play a key role in many types of installation – as tripping batteries in substations, for example, and as a power source for UPS systems in data centers and industry. In almost all of these applications, the unexpected failure of a battery when it is called upon to supply power can have far-reaching and very expensive consequences. In fact, it is by no means inconceivable for the consequential costs of a battery failure in the electricity transmission network or in a nuclear power station to cost millions of pounds or dollars.

The best strategy for avoiding such incidents is, without a doubt, regular battery testing, and a number of techniques have been developed to make this as convenient as possible. Of these techniques, discharge testing is the one that provides the most accurate and reliable determination of battery condition, although impedance testing, which can be carried out quickly and easily, is a valuable method of routinely monitoring battery status between discharge tests.

While discharge testing is usually seen as the best way of deciding whether or not a battery is in need of replacement, it does have one important limitation: it looks at the health of the complete battery and provides no information about individual cells. This means that the most likely reaction to discovering a defective battery in a critical application is to completely replace it. This is, undoubtedly, an effective remedy but, as the problem with the existing battery was most likely limited to one or two faulty cells, it’s also

Remains Portable for use in Multiple Fields and Plants.

Cell monitoring and the replacement of individual defective cells frequently allow the life of a battery to be very substantially extended, yielding big cost savings and minimizing the potential environmental impact of end-of-life battery disposals.

a very inefficient approach in terms of cost and environmental impact, as the materials making up storage batteries are not noted for their environmental friendliness.

What is needed is a way of pinpointing the defective cells and, not surprisingly, test equipment manufacturers offer products that are designed to do exactly this. The way in which these products operate is very straightforward; they simply monitor the voltage of the individual cells in a battery while a discharge test is being performed. Any cell where the output voltage falls faster than it should, based on a comparison with the manufacturer’s data, is quickly identified as faulty and in need of replacement.

While the principle of operation of these cellmonitoring devices is simple, the implementation varies greatly from manufacturer to manufacturer. Many cell-monitoring products are designed to be installed permanently on a battery, which is an expensive option if multiple batteries need to be tested and monitored. Other cell-monitoring devices are cumbersome to connect and use or are limited in the number of cells per battery they can accommodate.

The ideal solution is a modular system that uses one voltage monitor module per cell with the modules linked by simple plug-in connections. The modules report back to a software package that analyzes the results and flags failing cells. The modules must be easy to connect to the cells using, for example, some form of spring-loaded connector, with provision for other options to cater for difficult applications.

The testing is performed in line with the International Electrotechnical Commission (IEC) test method, and complies fully with North American Electrical Reliability Corporation (NERC) and U.S. Federal Energy Regulatory Commission (FERC) requirements, confirming that it is suitable for use in even the most critical applications.

Using a cell-monitoring system of this type adds little to the cost of testing a battery and has no significant impact on the time needed to carry out the test. It does, however, provide invaluable additional information that positively identifies defective cells, allowing these to be replaced to restore the battery to health.

This approach cannot, of course, be continued indefinitely. Ultimately the battery will age to the point where a complete replacement is essential. Nevertheless, cell monitoring and the replacement of individual defective cells frequently allow the life of a battery to be very substantially extended, yielding big cost savings and minimizing the potential environmental impact of end-of-life battery disposals.

Klas Björck is product manager, battery and current products, for Megger. Working from Megger’s Täby, Sweden office (near Stockholm), Björck focused on electronic engineering in high school and went on to study analog and digital electronics, along with mechanical engineering, in college. He’s spent the last 25 years with the same company (which was purchased by Megger), working with development, service, support, distributors and customer training. On a personal note, Klas enjoys sailing, ice skating, and skiing.

Substation Testing As Easy As

Spend More Time Testing, Less Time Training

Vanguard’s precision substation testing instruments are designed to be intuitive and easy to use so that you can focus on testing instead of wasting time in training. Our versatile instruments offer a built-in thermal printer and on-board test record storage so that tests can be conducted in stand-alone mode in the field. A computer interface is also offered so that tests can be easily conducted from a PC.

And all of our instruments are competitively priced to provide cost-effective accuracy. For a virtual experience of our instruments, check out the interactive demos on our site at:

www.vanguard-instruments.com/demos

WHAT DO I DO IF THE BREAKER TRIPS ?

IF THE BREAKER TRIPS?

BY JAMES R. WHITE, Training Director, Shermco Industries, Inc.

There are two reasons a circuit breaker will trip open: there is an overcurrent condition, either an overload or a short circuit, or the circuit breaker is malfunctioning. In either case, there’s a problem that has to be found and corrected before the circuit breaker can be reset. One thought to keep in mind from a safety standpoint – if one is troubleshooting an electrical device or circuit, that means there is a problem and the device is no longer operating normally. When troubleshooting circuit breakers, exercise caution as they can and do fail when reset.

OSHA in 29CFR1910.334(b)(2) states, “Reclosing circuits after protective device operation. After a circuit is deenergized by a circuit protective device, the circuit may not be manually reenergized until it has been determined that the equipment and circuit can be safely energized. The repetitive manual reclosing of circuit breakers or reenergizing circuits through replaced fuses is prohibited.

Note: When it can be determined from the design of the circuit and the overcurrent devices involved that the automatic operation of a device was caused by an overload rather than a fault condition, no examination of the circuit or connected equipment is needed before the circuit is reenergized.”

The first part of this section requires that the circuit breaker and circuit be checked and found to be safe. The steps required depend on the type of circuit breaker. The first step should be to secure the circuit breaker. Physically set the circuit breaker

Figure 1:

to the OFF position. Molded-case circuit breakers have a nasty habit of not opening their contacts completely in a trip operation. They will not carry current, but they will give you a shock.

When a circuit breaker trips, it deenergizes the load connected to it. These loads must be secured by turning them off so they are not reenergized as soon as the circuit breaker is closed. If the circuit breaker feeds a process line, that process may require product or materials to be removed so it can be safely started again, and computer-controlled machinery may require a reset. At this time, an inspection should be made to determine if there are any obvious signs of an electrical problem such as smoke, burn damage to equipment, evidence of overheating, or small fires. If the equipment is located outdoors, inspect for evidence of short circuits caused by animals or reptiles entering the equipment or climbing poles. This is a huge problem in some areas (Figure 1).

After a circuit is deenergized by a circuit protective device, the circuit may not be manually reenergized until it has been determined that the equipment and circuit can be safely energized.

Figure 2: Arc-Damaged MCC Bucket

IF THE BREAKER TRIPS

The connected circuit must be tested and it must be verified that no short circuit exists. Reclosing a circuit breaker into a short circuit could cause the circuit breaker to fail violently, as it is weakened when it interrupts a fault at or near its interrupting rating. Test the circuit for the absence of voltage, then test the load side of the circuit phase-to-phase and phaseto-ground using an insulation-resistance test set. Do not mistake a control power transformer, potential transformer, or load device for a short-circuit, as any of these devices can appear as a low resistance. Disconnect these devices until an acceptable minimum resistance is measured. Wear correctly rated arc-flash and shock protective clothing and equipment during these tests.

If it is determined that the trip operation of the circuit breaker was caused by an overload instead of a short circuit, it can be returned to service without further action, as explained in the note to 29CFR1910.334(b)(2). If the circuit breaker interrupted a fault, it must be determined that the circuit breaker is fit for continued service.

DAMAGE FROM INTERRUPTING FAULTS

Internally, a circuit breaker that interrupts fault-level current will have varying degrees of damage, depending on how high the short-circuit current was and the interrupting rating of the circuit breaker. The closer the short-circuit current is to the circuit breaker’s interrupting rating, the greater the damage will be. The contacts will erode, the insulation will accrue thermal damage, and carbon and copper from the arcing will be distributed inside the arc chutes and possibly to other parts of the circuit breaker. Each time a circuit breaker interrupts a fault the circuit breaker is damaged in this way, and the damage is cumulative. At some point the circuit breaker will fail in service, causing damage to surrounding equipment and possibly injury to workers (Figure 2).

Reclosing into a fault is a common mistake made in the field. We used to call it clearing the fault. The dispatcher would tell us to reclose a circuit breaker in hopes it would blow free of its contact with ground. If it didn’t, we would often be instructed to try a second and possibly a third time. If it did not clear, we would go find the problem. It was usually fairly easy at that point to locate. Sometimes, the circuit breaker would fail

Do not mistake a control power transformer, potential transformer, or load device for a shortcircuit, as any of these devices can appear as a low resistance.

Figure 3: Sealed-CaseMolded-CaseCircuitBreaker Sealed-Case Molded-Case Circuit Breaker

IF THE BREAKER TRIPS

when reclosed, and that failure was pretty dramatic at times. OSHA states in 29CFR1910.334(b)(2), “The repetitive manual reclosing of circuit breakers or reenergizing circuits through replaced fuses is prohibited.” The word prohibited is only used this once in the regulation and should be taken literally.

A sealed-case, molded-case circuit breaker, as shown in Figure 3, cannot have its case opened to inspect it, but it can be inspected for any signs of damage to the case or terminal connections. If the short-circuit current exceeded the circuit breaker’s interrupting rating, the case could show signs of external burning or even cracks or rupture. The terminal connections on molded-case circuit breakers are known to be a source of problems. If the connections loosen, which they often will, the connection resistance increases and heating begins. Over time, the conductor can become annealed from the heat generated by the loose connection. Once a wire has annealed, its resistance is so high that the heat generated from current flow will melt the wire’s insulation and could cause a fire. At a minimum, that section of wire must be replaced and the terminal lug inspected to ensure it was not damaged.

A sealed-case, moldedcase circuit breaker, cannot have its case opened to inspect it, but it can be inspected for any signs of damage to the case or terminal connections.

In general, sealed-case molded-case circuit breakers are designed to be throw-away items, as they cannot be repaired. There are some tests that can be performed to determine if they are suitable for continued service, however. A contact resistance test can be performed to determine if the circuit breaker can safely carry current. Molded-case circuit breakers often will have much higher contact resistance readings than other types of circuit breakers because of the small contact structure and surface area. The best gage of serviceability is to perform the test on all three phases using a microhmmeter with the circuit breaker closed. The contact resistance between the highest reading and the lowest reading should not exceed 50%.1 If the difference is greater than 50% the circuit breaker should be discarded. If a new circuit breaker is available of the same manufacture, type, and ampere rating, the readings from the faulted circuit breaker can be compared to that of the new circuit breaker. There’s no rule-of-thumb to consult on this, but if in your judgment the readings seem to be too high, replace the circuit breaker.

The second test is an insulation-resistance test. This test is performed phase-to-phase and phase-to-ground with the circuit breaker closed. Since the circuit breaker is out of the panel, it must be tested to a metal plate or bolted into a spare panelboard for the phase-to-ground test. With the circuit breaker open, test from the line-side of the circuit breaker to the load-side. Minimum test voltages are 500 V dc for 120/208-240 V circuit breakers and 1,000 V for 277/480 V circuit breakers.1 Minimum insulation resistance should be 25 MΩ for the 500 V test and 100 MΩ for the 1,000 V test. 1

Generally, these types of circuit breakers can be refurbished. They can be disassembled, cleaned, repaired, and returned to service by qualified shops. Since they can be opened, an internal inspection is warranted if they interrupted a short circuit. The first step is to remove the circuit breaker from its enclosure. Follow the manufacturer’s recommended procedures and safe work practices. On power circuit breakers, remove the arc chutes and on insulated-case circuit breakers, remove the front cover. There may be several components that must be removed to gain access to the arc chutes and contact structures of an insulated-case circuit breaker.

IF THE BREAKER TRIPS

Inspect the arc chutes for signs of damage, including cracks that extend through to the other surface, carbon tracking, erosion of separator plates or, thermal damage to fiberglass components, as shown in Figures 4a, 4b and 4c. Also inspect for any debris that may be caught in the muffler/vent assembly and for metal spatter adhering to the separator plates. Metal spatter is caused during heavier faults melting the arcing contacts and blowing the metal up onto the separator plates. It can usually be removed by running a screwdriver between the plates and scraping the metal droplets off. In some cases the arc chute will need to be disassembled and cleaned. Arc chutes constructed of asbestos should not be sanded or beadblasted to remove carbon. Arc chutes showing excessive glass-beading should be replaced, as the ceramic material is beginning to break down under the intense heat of the arc and the silicone is separating from the ceramic, causing the beading. This usually occurs in the throat of the arc chute where the contacts open.

Inspect the backboard assembly for carbon tracking or heat damage. Some light burning is acceptable, but be aware that heavier burning could be an indication of circuit breaker misoperation or operation at or near its interrupting rating. Insulating components that show more than surface damage should be replaced. Inspect inside the circuit breaker for any loose, misaligned, or damaged components, as well.

Inspect the contacts for damage. The arcing contacts will always show some damage from interrupting the arc. They are made of an alloy containing zinc, tungsten, or other harder metals so they can interrupt the arc. Look for excessive erosion, or erosion of the main contacts. Arcing damage to the main contacts indicates a misadjusted circuit breaker or excessively-damaged arcing contacts. Expect to see some minor pitting on main contacts, which is normal. Inspect the contact surfaces for cracking. Figure 5a shows the A-phase arcing contact from a circuit breaker. The cracks were not visible until it was cleaned using an abrasive pad. Figure 5b shows B-phase contact from that same circuit breaker. During normal operation this contact would be able to interrupt the relatively small currents, but during a fault the cracking on the contact face allowed the arc to melt and vaporize the softer metal under the contact face. The circuit breaker should not be returned to service if the contact structures show excessive arc damage.

IF THE BREAKER TRIPS

Operate the circuit breaker a few times at normal speed and watch for any indication of sluggishness. Ensure the contacts open completely. Lubrication issues can cause the circuit breaker to operate more slowly than designed or to not open all the way. If this happens during a fault, the circuit breaker and its enclosure could be heavily damaged, as it would be unable to clear the fault. Reinstall the arc chutes and perform a contact resistance and insulation-resistance test.

CONTACT RESISTANCE

The contact resistance test is performed in the same manner as for molded-case circuit breakers. With the circuit breaker closed, measure the resistance on each phase line-to-load. The contact resistance between the highest reading and the lowest reading should not differ by more than 50 percent. 1 If the difference is greater than 50 percent, the circuit breaker should be discarded. The rule-of-thumb value for low-voltage

power circuit breakers is that circuit breakers in very good condition will have contact resistances below 100 μΩ. If contact resistance exceeds 300 μΩ the circuit breaker requires service. The larger the circuit breaker ampere rating, the lower the contact resistance should be. A 3,000 A or 4,000 A frame power circuit breaker will probably have a contact resistance below 30 μΩ, and even as low as 16 μΩ, while a 800 A frame circuit breaker will be closer to 80 or 90 μΩ. Again, the 50 percent rule is a good guide. Medium-voltage air circuit breakers will have contact resistances much lower than for low-voltage circuit breakers. Typical values range from less than 20 μΩ to 80 μΩ. If the contact resistance exceeds 200 μΩ, maintenance is probably required.

INSULATION RESISTANCE

Test phase-to-phase and phase-to-ground with the circuit breaker closed for the insulation resistance test. Test to the circuit breaker’s metal frame for the phase-to-ground test on power circuit breakers, or to a metal plate for insulated-case circuit breakers. With the circuit breaker open, test from the line-side of the circuit breaker to the loadside. Minimum test voltages are 500 V dc for 120/208240 V circuit breakers and 1,000 V for 277/480 V circuit breakers. 1 Minimum insulation resistance should be 25 MΩ for the 500 V test and 100 MΩ for the 1,000 V test. 1 For medium-voltage air circuit breakers, the test voltage increases

Arcing Contact Failure

The contact resistance between the highest reading and the lowest reading should not exceed 50%. If the difference is greater than 50% the circuit breaker should be discarded

IF THE BREAKER TRIPS

to 2,500 V for 5 kV to 15 kV-class equipment and should have a minimum insulation resistance of 1,000 MΩ to 5,000 MΩ,1 depending on the voltage class of the circuit breaker. If in doubt about the condition of the circuit breaker, perform either a dc overpotential test or an insulation powerfactor test.

Since vacuum circuit breakers use a vacuum bottle in place of arc chutes and external contacts, there is less to inspect. Do check the bottle for any signs of damage, including arcover or cracks. A vacuum bottle integrity test is necessary, as a bottle failure could cause extensive damage under certain circumstances, Figure 6. Bad bottles often do not fail when the circuit breaker is opened, as the load is interrupted on all three phases. If the breaker is closed into a fault or a circuit that has a high starting current, it can fail violently. Refer to the manufacturer’s instruction book for appropriate test voltages.

Bottle failure is usually indicated by the test set tripping its circuit breaker.

SUMMARY

If the circuit breaker passes the tests and inspections described above, it can be returned to service.

James R. (Jim) White is the Training Director of Shermco Industries, Inc., in Dallas, Texas. He is the principal member on the NFPA technical committee “Recommended Practice for Electrical Equipment Maintenance” (NFPA 70B). Jim represents NETA as an alternate member of the NFPA Technical Committee “Electrical Safety in the Workplace” (NFPA 70E) and represents NETA on the ASTM F18 Committee “Electrical Protective Equipment For Workers”. Jim is an IEEE Senior Member and in 2011 received the IEEE/PCIC Electrical Safety Excellence award. Jim is a past Chairman (2008) of the IEEE Electrical Safety Workshop (ESW).

1 ANSI/NETA MTS-2011, “Standard for Maintenance Test Specification for Electrical Power Equipment and Systems”, National Electrical Testing Association, 2011.

Figure 6: Vacuum Bottle Failure and Damage to Circuit Breaker

CAPACITOR TRIP UNIT

BY JIM BOWEN, Powell Industries

A capacitor trip unit is a prepackaged module that supplies power for tripping an ac controlled circuit breaker with discrete relays following the loss of the ac control voltage. Dc control utilizing a charger and battery bank is the more reliable method of supplying tripping power, but in installations of only one or two circuit breakers, sometimes it is difficult to justify the higher cost of the battery system.

The capacitor unit has a blocking diode to maintain the storage capacitor charged at the peak ac voltage. In case of loss of ac, the blocking diode prevents the capacitor from discharging due to upstream loads. The standard product holds sufficient charge to trip the breaker for 12 seconds after loss of ac voltage. The capacitor trip units are also available in a battery-assisted model. This model protects against losing power for time period of up to two days by having a small gel cell battery support the voltage. Due to the long charge retention time these units are usually supplied with a toggle switch to disconnect the unit and discharge the capacitor to allow trip circuit maintenance.

Once the load is connected, the stored 30 wattseconds of energy dissipates very quickly. The load is typically either a lockout relay or a circuit breaker trip coil. One capacitor trip unit should be provided per coil load. For example if you have two lockout relays and a trip coil -- this circuit requires three of the cap trip units. The unit can not support indication lights, healthy monitoring relays, or any other such continuous loads, as they would drain the energy stored in the capacitor when the source voltage is lost.

There are no set points to the cap trip unit and most of the designs do not permit monitoring relays to warn that the capacitor is not working. It can hold a charge for a surprisingly long period of time; therefore, it is important that the user have a written procedure for discharging the unit and shorting out the capacitor prior to working on the control circuit to prevent an electric shock hazard.

The most effective way of discharging the capacitor is to utilize the unit energy to open the circuit breaker. To accomplish this, disconnect the ac control power and operate the circuit breaker via the cap trip unit. In so doing, not only do you partially discharge the capacitor but you also get a functional test as a bonus. The capacitor may still have some residual charge and should be discharged prior to touching any conductor in the trip circuit. Discharge the additional stored energy by installing a jumper with a resistor in series. The battery assisted units have a disconnect switch wired into the front of the unit.

Obviously for one to disconnect the ac a disconnecting means for the ac is required. This can be a pull-apart fuse block, a circuit breaker, or a local knife switch depending on how the circuit is set up.

If site safety requirements make it difficult to install a jumper on a circuit that may be in excess of 50 volts to ground, a push button may be installed to discharge the remaining capacitor charge. I do not recommend a maintained switch, as there is too great of a chance of energizing the circuit with the capacitor trip circuit shorted.

In closing, remember there is a limited life to battery assisted capacitor trip units. It is critical that this device be included in the site maintenance plan.

Jim Bowen graduated from Texas A&M University in 1976 with a BSEE. He has worked for SIP Engineering as a power engineer and for Exxon in all facets of electrical engineering in the petrochemical process. He held the position of regional engineer for Exxon Chemicals Europe for three years. In January of 1997, Jim joined Powell Electrical Manufacturing Company as Technical Director, providing leadership, training, and mentoring to both internal and external electrical communities.

Circuit Tracers the test equipment answer

VLF and Tan Delta (30 and 60kV Systems)

Off Line Partial Discharge

DC Hipot Testing (To 200kV)

Power Factor / Capacitance and Dissipation

Insulation Analyzers (To 15kV)

Cable Fault and Route Location

Fiber Optic TDR

BATTERYSAFETY CONCERNS

BY STEPHEN CANALE, American Electrical Testing Co.

There are few components in an electrical system that expose workers to the number and range of hazards as do battery systems. Exposed electrical conductors, hazardous gasses, dangerous chemicals, potential for explosions, and heavy lifting are just a few of the hazards present when working with and around batteries.

The following provides some insight into these potential dangers and proposes ways to keep safe when working on or near battery systems. Our focus will be mainly on wet cell battery systems which are typically used in switchgear applications. However, many of the issues are also relevant when dealing with other types of battery systems.

SO DANGEROUS?

There are several hazards that workers need to be aware of when working with or around batteries:

ELECTRICAL HAZARDS

CHEMICAL HAZARDS

Most wet cell batteries contain an acid (usually sulfuric), as well as heavy metals (usually lead). If a lead-acid battery is unsealed, there is the potential for spills and leaks which can cause acid burns upon the skin if a worker is exposed. Additionally, lead is hazardous when ingested. Other batteries contain different chemical health hazards. They can contain lithium, cadmium, bromide, and other heavy metals that can potentially be a health hazard if ingested, injected, or absorbed in large enough quantity.

EXPLOSIVE HAZARDS

Batteries expose workers to especially dangerous electrical hazards because their source of potential is always exposed and they contain no overload protection. Getting across the terminals of a battery is hazardous. Workers must be extra careful to avoid this hazard. A terminal short is caused when the positive and negative terminals are connected to each other via a conductive item. The terminals being shorted against each other for a long enough period of time can cause an overload in the battery and potentially a spontaneous failure due to overheating. Additionally, the shorting of two terminals on a battery can generate sparks which can cause flammable gasses (see explosive hazards below) to ignite or explode. Even if the battery does not fail due to the short circuit, the life of the battery is significantly degraded due to the heavy load placed upon it and the significant heating that occurrs.

Hydrogen gas is generated as a by-product of the battery’s chemical reaction. This off-gas, if not properly vented, can build to a point where it can become explosive (four percent is the lower explosive limit, LEL). Exposing this gas to sparks or open flames can cause a significant explosion.

LIFTING HAZARDS

Batteries are heavy in relation to size. Workers must take special care when attempting to lift or move batteries. Get aid when moving a heavy battery or use a lifting aid as needed. If using a lifting aid, training in the use of that equipment is required.

As with any potentially hazardous work, it is important to gain a good understanding of the work at hand and of the components involved. The battery manufacturer’s installation and maintenance manuals are a good source of information and should be read thoroughly before beginning work. In addition, workers should take the time to read and understand the various standards that are available relating to battery systems (NFPA 111, IEEE 450 and 484, and IEEE 1187 and 1188 are recommended). There are also new IEEE standards relating to spill containment (IEEE P1578) and battery technician qualifications (IEEE P1657), presently in draft form, which are worth a look.

A comprehensive prejob briefing or job hazard analysis should be performed with all workers to discuss the planned tasks and each of the potential hazards in detail.

IS THE BATTERY AREA SAFE?

As discussed earlier, batteries present significant safety hazards and must be treated with great caution. Only qualified personnel should be allowed to enter an area where batteries are in use. Qualified personnel are knowledgeable

in all aspects of battery safety, as well as with spill containment and mitigation techniques. Qualified personnel are also knowledgeable in battery maintenance procedures and with general electrical safety. (For more details on Qualified Persons, refer to NFPA-70E.)

When entering an area containing batteries, the first step is to take a look around the area and confirm that proper safety items are in place. The space is required to be well ventilated, well lit, and must have unobstructed access to exit doors. Safety signage that provides emergency responders with clear indications of the potential dangers is required. Check that fire extinguishers (class ABC) are strategically placed throughout the area. The battery manufacturer’s Material Safety Data Sheets (MSDS) sheets must be available.

There must be at least one eye wash station nearby (as close to the point of exposure as possible not to exceed 25 feet) and it is required to be adequately filled with at least a 15 minute supply of clean water. Never flush eyes with acid neutralizer solution – always use clean water. If battery jars or cases are to be installed or replaced, there is a heightened possibility of an acid spill. During the handling of battery jars, they could be dropped or tipped, causing acid to leak and to potentially find its way onto worker’s skin. In this case, a body wash station must also be readily available and it is also required to be filled with clean water. If a body wash station is not available, it is recommended to purchase a portable station and place it nearby, again within 25 feet of the exposure area.

Never allow smoking, open flames, or any activity that could result in sparks or electrical arcing in any battery area. Metal ladders and any other large or long conductive objects should also be kept out of the battery area. Jewelry should never be worn in the battery area. Additionally, taping conductive tools does not adequately prevent the tool from inadvertently causing a spark. Always use insulated tools that are listed for the voltage present and test equipment that is insulated and properly fused.

Other items recommended to be readily available while working on battery systems include:

(a mixture of one pound baking soda to one gallon of clean water, or other acceptable solutions). This solution is used to neutralize any acid that may contact the skin or spill

to the floor. It can also be used to clean the battery jars and to neutralize any acid that may spill onto surrounding areas.

possible battery acid leaks or spills.

hold battery jars. These containers should be readily available to contain battery jars in the event any jars become cracked or broken. The container will hold the jar itself and contain any acid that leaks from the jar.

SPECIAL PERSONAL PROTECTIVE

Battery work requires its own unique set of PPE. Workers need to protect themselves from the hazard of electrical shock, exposure to battery acids, and potential explosions as well as be prepared for a possible spill of battery acid.

Some of the recommended PPE include:

1. Chemical Resistant Goggles and Face Shield–It is important to keep eyes protected in the event of a battery explosion. Goggles and a face shield must be worn at all times while working on batteries to help protect from potential explosions. Another good reason to always wear wrap-around goggles is the tendency most people have to rub their eyes. When working around batteries, it is easy to get acid on hands and gloves. The goggles will help prevent the rubbing of eyes with contaminated gloves and hands.

2. Chemical Resistant Gloves and Aprons–Battery acid is typically present on the outer part of all battery jars. Acid seeps through the battery terminal connections, is dripped onto the jars when specific gravity readings are taken, and is vented during the battery charging process.

Never allow smoking, open flames, or any activity that could result in sparks or electrical arcing in any battery area.

SAFETY CORNER

Wearing gloves and an apron will help keep this acid off of skin and clothing.

3. Protective overshoes and overalls.

4. A hard hat where applicable.

PPE used when working with batteries will quickly become contaminated with grease, dirt, and battery acid. Thoroughly clean all PPE after each day to preserve its useful life. Replace batteryrelated PPE frequently.

MONITORING BATTERY CONDITIONS FOR SAFE OPERATION

Battery systems should be inspected for general condition on a regular basis, preferably at least weekly, to ensure they are in a safe condition. Some of the items to monitor are:

GENERAL BATTERY CONDITION:

During inspection the general condition of each battery jar should be noted. Each jar should be checked for cleanliness and cleaned if necessary. Use a clean, damp cloth for cleaning battery jars. Never use chemical cleaners as these can erode the battery jars. If a neutralizing solution is used to clean the battery, follow up with a clean, damp cloth to clear any residue left by the solution.

Check each jar’s casing for signs of cracking. Small cracks can form on the jars and these can grow to the point where acid begins to leak. Any jars showing signs of cracking should be replaced as soon as possible.

The general condition of each battery terminal post should be checked. Large buildups of oxidation should be removed and noted. Any significant signs of acid seepage through the posts should also

be noted and cleaned. Discoloration of the posts can also be a sign of a pending problem. In general, problems noted with any posts should be followed up by a removal, cleaning, and reinstallation of the connections at the post.

Where cable connections exist, carefully inspect the connection. Proper strain relief should be in place and there should be no strain placed on the terminal posts. Posts are made of soft lead, and excessive strain can easily break the post resulting in a dangerous electrical hazard.

Each jar in a wet cell battery should contain a flame arrester that sits in an opening at the top of the jar. These arresters reduce the effect of any possible explosion of the jar. Each of these arrestors should be carefully inspected for damage and for any blockage. Damaged flame arresters should be immediately replaced. Blocked or dirty arresters should be thoroughly cleaned with a neutralizing solution. If any arrester cannot be completely cleaned, it should be replaced.

PLATE CONDITION AND SEDIMENT BUILDUP:

The interior plates of a battery can become loose or broken. A broken plate can make contact with other plates within the battery and this contact can cause a buildup of heat within the battery jar. This heat, if in the presence of enough hydrogen and oxygen, can cause an explosive failure of the battery. Any battery jar with broken plates should be removed from the battery string.

The chemical reactions that take place within a battery cause a deterioration of the internal plates. This is a normal process that will result in a small amount of sediment at the bottom of each jar. A

regularly to ensure that the battery is not overcharged. An overcharging battery will produce higher levels of highly flammable hydrogen gas.

thorough inspection of the level, coloration, and size of the sediment particles can be helpful in determining the health of the battery. Excessive or unusual sediment can indicate a problem. In addition, sediment levels can potentially reach the bottoms of the battery plates, causing internal shorts that may result in explosion.

CHARGING LEVEL:

Battery charger voltage and ripple voltage should be checked regularly to ensure that the battery is not overcharged. An overcharging battery will

produce higher levels of highly flammable hydrogen gas. Overcharging and creating high heat volumes, or overcharging and creating an incidental spark, can cause this off gas to ignite, and the battery will explode.

ELECTROLYTE LEVEL:

The level of electrolyte in each jar should be monitored. Jars will have fill level lines, and electrolyte levels should always be maintained between these lines. Low electrolyte levels can be an indication of a problem within the battery or

SAFETY CORNER

possible overcharging. Allowing the electrolyte to drop below the tops of the battery plates can result in an explosion.

Always fill batteries according to the manufacturer’s recommendations. Be careful not to overfill any jars as this can result in spewing of battery acid during charging.

BATTERY INSTALLATION/ REPLACEMENT SAFETY

The installation, maintenance, or replacement of batteries poses some additional hazards of which workers should be aware of. Workers should be ready for the possibility of a dropped, toppled, or damaged battery. Also, a floor scraping squeegee to help manage any spills, adsorbing booms for containing any spills, and plenty of acid neutralizers should be kept close by.

When handling battery jars, keep in mind that they are much heavier than they appear. Proper lifting techniques and lifting equipment should always be used.

When installing batteries, pay close attention to proper polarity and be aware of the possibility of electrical arcing when connecting battery jars.

Workers should also be aware that battery jars crack fairly easily. Battery jars should be gently eased into place, never dropped in. When placing jars on the floor for staging, be sure that the floor is completely clean. Placing a battery jar onto any small objects that might be on the floor can easily cause the jar to crack, resulting in battery acid leakage. Soft padding placed on the staging floor is also helpful.

Finally, special precautions must be made when transporting batteries. Cracked or broken battery jars must be contained within an acceptable, acid resistant, and leak proof container. Transport vehicles must bear proper hazardous waste signage, contain a copy of the MSDS sheet for the battery, and be equipped with proper safety equipment.

Spent or damaged batteries must also be correctly disposed of per the applicable EPA and state guidelines. Documentation of the proper disposal of the battery must also be maintained according to state and federal environmental regulations.

SUMMARY

Battery work poses many special hazards. Workers must always be acutely aware of these hazards by keeping the following points in mind whenever undertaking battery work:

reading the available standards all of the required safety equipment

performing daily job briefings and by wearing and using proper PPE

terminals and the hazards they pose

safe by performing regular inspections

prepared for the special hazards associated with lifting and handling batteries.

Stephen Canale has worked in the electrical industry for over 32 years, specializing in backup and emergency power Systems. He holds degrees and certifications in digital electronics, project management, and software development.

For the past 12 years Stephen has worked as Special Projects Manager for American Electrical Testing, Inc. He also spent 10 years as Director of Field Operations for a major data center design/build firm, and has worked as a field engineer for several uninterruptible power system manufacturers.

Stephen is also lead developer and owner of ePowerForms, a software application used for collecting and managing electrical testing data.

From big city to small town, east to west, North America to Europe, we are expanding our resources and service center locations to better serve you.

Contact Shermco Industries for safe, reliable testing, repair, professional training, maintenance and analysis of rotating apparatus or electrical power distribution systems for all market segments, including industrial, commercial, petrochemical, utilities and more.

CURRENT DISTRIBUTION IN RESISTIVITY MEASUREMENT

BY JEFF JOWETT, Megger

Most common electrical applications require current to be specifically controlled through meticulous circuit design. Earth testing is highly atypical in that current has extraordinary freedom to define a path. Accordingly, it is both instructive and essential to examine current distribution in a ground test.

With current injected into the ground at point A and leaving at B, a plane QRST can be defined midway between A and B and at right angle to a line joining them (Figure 1). From the symmetry, current flow at all points crossing this plane will be perpendicular to it. Examining current density at key points along this plane will show how current is distributed. Consider a point P, defined by a depth z, a perpendicular distance x from the plane, and a perpendicular distance y from the line AB. The distances AP and BP are {(D – x) + y + z } / and {(D + x) + y } / , respectively. The potential P from a current entering at A is:

+ y } /

...Where I = current and = resistivity.

Similarly, the distance BP is the negative of the same value. The total potential at P, then, is:

+ y } / – 1/{(D + x) + y } / ]

The potential gradient perpendicular to the plane in the x direction is:

d + y } / + (D + x)/{(D + x) + y } / d

On the plane, x = 0, so that the potential gradient perpendicular to it is: } / + y } / ]

Current density is equal to potential gradient divided by resistivity , so at any point on the plane:

+ y ) / ]

Figure 1: Calculation of Current Density

Figure 2: Variation of Current Density with Depth.

Figure 3:

At a point O midway between A and B, both y and equal zero and so the current density at this point is:

Rearranging, 0D , and substituting this into the equation for gives:

0 = D /(D + y ) /

The current density with depth perpendicular to O is given by:

0 = D /(D ) / ] /

Values calculated from this equation are plotted in Figure 2. Note that it is commonly thought that when electrodes are placed in the familiar configuration of four in a straight line equidistant, then the current penetrates to a depth equivalent to the spacing interval. This notion is the basis for prospecting, where changes in resistivity with depth are plotted to reveal the depth of bedrock, buried objects, and the like. Note that in Figure 1 the current electrodes are at a distance 2D, making the distance between adjacent electrodes in a 4-pin arrangement 2D/3. The corresponding value of z/D is 2/3, and the graph shows that at this value, the current density is still about 58 percent of surface density, so a considerable portion of total current must penetrate to greater

depths. A final note is that ideal models are based upon prescribed contingencies, which may be present in widely varying degree in a real situation. In this model, soil is figured to be perfectly homogeneous in all directions, which of course is not likely to be the case in actuality. So while the theory serves well to establish practice and procedure, expectations must not be too narrowly defined, and interpretation of actual results must take into consideration the local realities. Accordingly, in field practice, the familiar Wenner four-electrode configuration and procedure has proven to be the most practical.

Although soil homogeneity is a desirable factor in primary research, in actual practice, it is non-homogeneity that may be sought. This is where resistivity measurements are being taken in order to locate changes in underground soil structure, such as water table, bedrock, or buried objects. Lee’s Method of Partitioning, as it is known, was designed to address such applications, but as will be shown, pertains to lateral mapping. In this adaptation, five electrodes are utilized instead of four as has been previously shown (Figure 3). But only four are used at a time. As usual, the outer electrodes are to establish the test current, while the three inner electrodes sense voltage drop in alternate tandem configurations. The first is made across A and B, and the second across B and C. From symmetry, the potential of B is zero. The potential of A is:

Figure 4: Central Electrode System.

This will also be the potential between A and B. If RAB is the resistance between A and B, then it will equal VAB/I (Ohm’s law), and therefore:

Examining the second pairing of potential electrodes shows that:

Since the two measurements are made without moving the electrodes, if the values obtained do not agree, then the soil is non-homogeneous. The non-homogeneity can be mapped and some conclusions drawn as to its nature by changing the value of a or moving the system. But it can be seen that this method applies to lateral mapping, not vertical.

Another adaptation is called the Central Electrode System (Figure 4). One of the two current electrodes is placed at a considerable distance in order to largely eliminate any influence to the potential across B and C by current leaving at the remote electrode. The potential difference between B and C is defined by current entering at A:

VAB a – 1/(a + b a(a + b)]

Again, if RAB equals /I, then resistivity is:

a(a + b)R b

It can be seen, then, that with just the resistance reading taken from the meter and the dimensions of the setup, the resistivity values can be relatively easily calculated. The formula is a bit more complex than the Wenner formula, but the configu-

ration of electrodes saves time over the Wenner Method. With one current probe removed at a distance to be effectively out of the measurement, no specific distance relationship to it must be maintained, and so only the potential probes need be moved in order to change the sphere of measurement. In difficult terrain, it is expected that this saving will more than offset the additional time on a calculator. The additional space requirement compared to the more concise Wenner setup can be an added complication, however, and so these factors need all be balanced before deciding to use this method.

The obvious question then is how to set the remote probe in order to achieve the presumed result. This can be done mathematically, too. As has been seen, potential difference between B and C due to current leaving at D is:

d(d + b)

By selecting a limit value for this potential to 1 percent of that entering at A:

(d + b) > 100

Or:

d(d + b)

a(a + b) > 100

Making a and d large compared to b, then:

d /a > 100 or d/a > 10

Therefore, d should be made more than 10 times a. A modification to ensure uniform current distribution away from A is to have D configured, not as a single probe, but as a concentric ring around A, with all the electrodes comprising D connected together.

Additional method modifications exist in order to confer an advantage in atypical situations, and these will be presented in a future column. Next, however, will be a further examination of current travel as expressed through rocks and minerals.

Source of information: “Earth Resistances” by G. F. Tagg, George Newnes Ltd, London

Jeffery R. Jowett is a Senior Applications Engineer for Megger in Valley Forge, the manufacturing lines of Biddle, Megger, and multiAmp for electrical test and measurement instrumentation. He holds a BS in Biology and Chemistry from Ursinus College. He was employed

James G. Biddle Co. which became Biddle Instruments and is now Megger.

ANSWERS

1. An indication that a vented lead-acid battery is in trouble is when its internal impedance increases ___% above its as-installed impedance.

b. When the internal impedance of a cell increases by more than 20%, it is an indication that the battery is starting to deteriorate and should be monitored more closely. This test is often referred to as the ohmic test and is performed by applying an ac voltage across the battery and measuring the internal impedance of the battery.

2. Which of the following is not an example of a VRLA (valve-regulated lead-acid) battery?

a. VRLA batteries (valve-regulated lead-acid) are increasingly used for various standby electrical power applications including emergency generators and switchgear. The most common types of VRLA batteries are gel cells and absorbed glass mat. These batteries are often referred to as maintenance free, although low maintenance would better describe them.

3. Sulfation in flooded-cell, lead-acid batteries is indicated by:

c. Sulfation results from the battery being in an undercharged state for an extended period of time. As the battery discharges, the active lead material on the plates will react with the sulfates in the electrolyte and form a lead sulfate on the plates. This appears as a white, granular deposit on the plates.

4. When performing a load test on a battery bank, what percent remaining capacity indicates the need to replace the batteries?

d. When battery capacity decreases to 80% of its initial rating, it is time to look for a replacement.

5. The only repair for sulfation is to:

a. Since sulfation occurs when a battery is in a discharged state, equalizing is the cure. The problem is that all of the sulfates usually do not recombine and the battery loses some capacity. This is a normal part of the charge/discharge cycle, but when a battery stays in a low state of charge, sulfation can be permanent. Battery shedding will also increase as the discharged electrolyte now contains more water and will soften the lead plate material. If that shedded material builds up to about halfway to the plates, a constant discharge begins between the shedded material and the plates, which results in a battery that will not maintain a charge.

NFPA Disclaimer:

considered an official position of the NFPA or any of its technical committees and shall not be considered to be, nor be relied upon as, a formal interpretation or promotion of the NFPA. Readers are encouraged to refer to the entire text of all referenced documents.

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ANSI/NETA STANDARDS UPDATES

If you have any questions about the ANSI/NETA Standards, including how to ensure that your equipment is tested in accordance with the ANSI/NETA Standards, please contact the NETA office at neta@netaworld.org or call 888-300-6382

The ANSI/NETA Standard for Acceptance Testing Specifications for Electrical Power Equipment and Systems is scheduled to be published as a revised document in 2013. These specifications cover the suggested field tests and inspections that are available to assess the suitability for initial energization of electrical power equipment and systems. The purpose of these specifications is to assure that tested electrical equipment and systems are operational, are within applicable standards and manufacturers’ tolerances, and are installed in accordance with design specifications. Work on this document began in the spring of 2011. Once completed, this standard will carry the designation of ANSI/NETA ATS-2013. The first public review period began on June 15, 2012 and closed on July 30, 2012. The Ballot Pool is currently full, but new applications will be held for review as openings are available.

On May 16, 2011, NETA received notification that the ANSI/NETA Standard for Maintenance Testing Specifications for Electrical Power Equipment and Systems was approved as a revised American National Standard. This document contains specifications which cover the suggested field tests and inspections that are available to assess the suitability for continued service and reliability of electrical power distribution equipment and systems. The purpose of these specifications is to assure that tested electrical equipment and systems are operational and within applicable standards and manufacturers’ tolerances and that the equipment and systems are suitable for continued service. It is available in hard copy, PDF, and CD Rom formats. Order your copy today at www.netaworld.org.

PARTICIPATION

The ANSI/NETA Standard for Certification of Electrical Testing Technicians was approved as an American National Standard on January 8, 2010. The document was originally approved as an ANSI standard in 2000. This standard establishes minimum requirements for qualifications, certification, training, and experience for the electrical testing technician. It also provides criteria for documenting qualifications and certification and details the minimum qualifications for an independent and impartial certifying body to certify electrical testing technicians.

CORRECTION

In the NETA World Journal, summer 2012 issue the NEC Code Making Panel Committee Report should have been attributed to Scott Blizard, American Electrical Testing Company. The report was incorrectly credited to James R. White, Shermco Industries. Apologies are extended to both authors who are valued contributors to the NETA World Journal.

Comments and suggestions on any of the standards are always welcome and should be

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Kevin Chilton

A&F Electrical Testing, Inc.

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Florence Chilton

ABM Electrical Power Solutions

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Jeff Militello

ABM Electrical Power Solutions

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Mark Anthony Gaughan, III

ABM Electrical Power Solutions

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Bill Hartman

ABM Electrical Power Solutions

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William (Pete) McKenzie

ABM Electrical Power Solutions

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Mark Robinson

ABM Electrical Power Solutions

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Frank Ceci

Advanced Testing Systems

15 Trowbridge Dr. Bethel, CT 06801 (203) 743-2001 Fax: (203) 743-2325

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Pat MacCarthy

American Electrical Testing Co., Inc.

480 Neponset St., Building 6 Canton, MA 02021-1970 (781) 821-0121 Fax: (781) 821-0771 sblizard@aetco.us www.99aetco.com

Scott A. Blizard

American Electrical Testing Co., Inc. 34 Clover Dr. South Windsor, CT 06074 (860) 648-1013 Fax: (781) 821-0771 jpoulin@aetco.us www.99aetco.com

Gerald Poulin

American Electrical Testing Co., Inc.

76 Cain Dr. Brentwood, NY 11717 (631) 617-5330 Fax: (631) 630-2292

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Michael Schacker

American Electrical Testing Co., Inc.

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Anthony Rosato

American Electrical Testing Co., Inc. 1811 Executive Dr., Ste. M Indianapolis, IN 46241 (317) 487-2111 Fax: (781) 821-0771 rramsey@99aetco.us www.99aetco.com

Rick Ramsey

American Electrical Testing Co., Inc. Green Hills Commerce Center 5925 Tilghman St., Ste. 200 Allentown, PA 18104 (215) 219-6800 jmunley@aetco.us www.99aetco.us

Jonathan Munley

American Electrical Testing Co., Inc. 1672 SE 80th Bella Vista Dr. The Villages, FL 32162 (727) 447-4503 Fax: (727) 447-4984 rhoffman@aetco.us www.99aetco.com

Bob Hoffman

AMP Quality Energy Services, LLC 516 Valleyview Terrace Huntsville, AL 35803 (256) 513-8255 www.ampqes.com

Brian Rodgers

Apparatus Testing and Engineering 11300 Sanders Dr., Ste. 29 Rancho Cordova, CA 95742 (916) 853-6280 Fax: (916) 853-6258 jlawler@apparatustesting.com www.apparatustesting.com

James Lawler

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Harold (Jerry) Carr

Applied Engineering Concepts 1105 N. Allen Ave. Pasadena, CA 91104 (626) 398-3052 Fax: (626) 398-3053 michel.c@aec-us.com www.aec-us.com

Michel Castonguay

Burlington Electrical Testing Co., Inc. 300 Cedar Ave. Croydon, PA 19021-6051 (215) 826-9400 (221) Fax: (215) 826-0964 waltc@betest.com www.betest.com

Walter P. Cleary

C.E. Testing, Inc. 6148 Tim Crews Rd. Macclenny, FL 32063 (904) 653-1900 Fax: (904) 653-1911 cetesting@aol.com

Mark Chapman

CE Power Solutions,LLC 4500 W. Mitchell Ave. Cincinnati, OH 45232 (513) 563-6150 Fax: (513) 563-6120 info@cepowersol.com

Rhonda Harris

CE Power Solutions of Wisconsin,LLC 3255 W. Highview Dr. Appleton, WI 54914 (920) 968-0281 Fax: (920) 968-0282 jimvh@cepowersol.com

James Van Handel

Dude Testing 554 Anderson Dr., Ste. A Romeoville, IL 60446 (815) 293-3388 Fax: (815) 293-3386 scott.dude@dudetesting.com www.dudetesting.com

Scott Dude

DYMAX Holdings, Inc.

4751 Mustang Circle St. Paul, MN 55112 (763) 717-3150 Fax: (763) 784-5397 gphilipp@dymaxservice.com www.dymaxservice.com

Gene Philipp

High Voltage Service, Inc.

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Mike Mavetz

DYMAX Service Inc.

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Bruce Robinson

DYMAX Service Inc.

4213 Kropf Ave. Canton, OH 44706 (330) 484-6801 Fax: (740) 333-1271 www.dymaxservice.com

Gary Swank

Eastern High Voltage

11A South Gold Dr. Robbinsville, NJ 08691-1606 (609) 890-8300 Fax: (609) 588-8090 joewilson@easternhighvoltage.com www.easternhighvoltage.com

Joseph Wilson

ELECT, P.C.

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Barry W. Tyndall

Electric Power Systems, Inc. 21 Millpark Ct. Maryland Heights, MO 63043-3536 (314) 890-9999 Fax: (314) 890-9998 t.lindemann@exch.eps-international.com www.eps-international.com

Steve Reed

Electric Power Systems, Inc. 557 E. Juanita Avenue, #4

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Louis G. Gilbert

Electric Power Systems, Inc.

4436 Parkway Commerce Blvd. Orlando, FL 32808 (407) 578-6424 Fax: 407-578-6408 www.eps-international.com

Doug Pacey

Electric Power Systems, Inc.

6753 E. 47th Avenue Dr., Unit D Denver, CO 80216 (720) 857-7273 Fax: 303-928-8020 www.eps-international.com

Thomas C. Reed

Electric Power Systems, Inc. 23823 Andrew Rd. Plainfield, IL 60585 (815) 577-9515 Fax: (815) 577-9516 www.eps-international.com

George Bratkiv

Electric Power Systems, Inc.

2601 Center Rd., # 101 Hinckley, OH 44233 (330) 460-3706 Fax: (330) 460-3708 www.eps-international.com

Garth Paul

Electric Power Systems, Inc. 1129 East Hwy 30 Gonzalez, LA 70737 (225) 644-0150 Fax: (225) 644-6249 www.eps-international.com

C.J. Theriot

Electric Power Systems, Inc. 56 Bibber Parkway #1 Brunswick, ME 04011 (207) 837-6527 www.eps-international.com

Jerry Jones

Electric Power Systems, Inc. 4100 Greenbriar Dr., Ste. 160 Stafford, TX 77477 (713) 644-5400 www.eps-international.com

Rob Alter

Electric Power Systems, Inc. 11861 Longsdorf St. Riverview, MI 48193 (734) 282-3311

t.lindemann@exch.eps-international.com www.eps-international.com

Teresa Lindemann

NETA ACCREDITED COMPANIES

Electric Power Systems, Inc. 827 Union St. Salem, VA 24153 (540) 375-0084 Fax: (540) 375-0094

virginia@eps-international.com www.eps-international.com

Bruce Eppers

Electric Power Systems, Inc. 915 Holt Ave., Unit 9 Manchester, NH 03109 (603) 657-7371 Fax: 603-657-7370 www.eps-international.com

Cindy Taylor

Electric Power Systems, Inc. 146 Space Park Dr. Nashville, TN 37211 (615) 834-0999 Fax: (615) 834-0129 www.eps-international.com

Larry Christodoulou

Electric Power Systems, Inc. 1090 Montour West Industrial Blvd. Coraopolis, PA 15108 (412) 276-4559 www.eps-international.com

Ed Nahm

Electric Power Systems, Inc. 6141 Connecticut Ave. Kansas City, MO 64120 (816) 241-9990 Fax: (816) 241-9992 www.eps-international.com

Joe Dillon

Electric Power Systems, Inc. 2495 Boulevard of the Generals Norristown, PA 19403 (610) 630-0286

t.lindemann@exch.eps-international.com www.eps-international.com

Teresa Lindemann

EPS Technology

29 N. Plains Hwy., Ste. 12 Wallingford, CT 06492 (203) 649-0145 www.eps-technology.com

Chris Myers

Electrical & Electronic Controls 6149 Hunter Rd. Ooltewah, TN 37363 (423) 344-7666 (23) Fax: (423) 344-4494 eecontrols@comcast.net

Michael Hughes

Electrical Energy Experts, Inc. W129N10818, Washington Dr. Germantown, WI 53022 (262) 255-5222 Fax: (262) 242-2360

bill@electricalenergyexperts.com www.electricalenergyexperts.com

William Styer

Electrical Equipment Upgrading, Inc. 21 Telfair Place Savannah, GA 31415 (912) 232-7402 Fax: (912) 233-4355 kmiller@eeu-inc.com www.eeu-inc.com

Kevin Miller

Electrical Maintenance & Testing Inc. 12342 Hancock St. Carmel, IN 46032 (317) 853-6795 Fax: (317) 853-6799 www.emtesting.com

Brian K. Borst

Electrical Reliability Services 1057 Doniphan Park Circle, Ste. A El Paso, TX 79922 (915) 587-9440 Fax: (915) 587-9010 www.electricalreliability.com

Electrical Reliability Services 1775 W. University Dr., Ste. 128 (480) 966-4568 Fax: (480) 966-4569 www.electricalreliability.com

Electrical Reliability Services 1426 Sens Rd. Ste. 5 LaPorte, TX 77571 (281) 241-2800 Fax: (281) 241-2801 www.electricalreliability.com

Electrical Reliability Services 4099 SE International Way, Ste. 201 Milwaukie, OR 97222-8853 (503) 653-6781 Fax: (503) 659-9733 www.electricalreliability.com

Electrical Reliability Services 5810 Van Allen Way Carlsbad, CA 92008 (760) 804-2972 www.electricalreliability.com

Electrical Reliability Services 8500 Washington St. NE, Ste. A-6 Albuquerque, NM 87113 (505) 822-0237 Fax: (505) 822-0217 www.electricalreliability.com

Electrical Reliability Services

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Electrical Reliability Services 7100 Broadway, Ste. 7E Denver, CO 80221-2915 (303) 427-8809 Fax: (303) 427-4080 www.electricalreliability.com

Electrical Reliability Services 348 N.W. Capital Dr. Lees Summit, MO 64086 (816) 525-7156 Fax: (816) 524-3274 www.electricalreliability.com

Electrical Reliability Services 6900 Koll Center Parkway, Suite 415 Pleasanton, CA 94566 (925) 485-3400 Fax: (925) 485-3436 www.electricalreliability.com

Electrical Reliability Services 10606 Bloomfield Ave. Santa Fe Springs, CA 90670 (562) 236-9555 Fax: (562) 777-8914 www.electricalreliability.com

Electrical Reliability Services 14141 Airline Hwy, Bldg. 1, Ste. X Baton Rouge, LA 70817 (225) 755-0530 Fax: (225) 751-5055 www.electricalreliability.com

Electrical Reliability Services 121 E. Hwy. 108 Sulphur, LA 70665 (337) 583-2411 Fax: (337) 583-2410 www.electricalreliability.com

Electrical Reliability Services 5580 Enterprice Parkway Ft. Myers, FL 33905-5507 (239) 693-7100 Fax: (239) 693-7772 www.electricalreliability.com

Electrical Reliability Services 2222 West Valley Hwy. N., Ste 160 Auburn, WA 98001 (253) 736-6010 Fax: (253) 736-6015 www.electricalreliability.com

Electrical Reliability Services 3412 South 1400 West, Unit A West Valley City, UT 84119 (801) 975-6461 www.electricalreliability.com

Electrical Reliability Services 6351 Hinson St., Ste. B Las Vegas, NV 89118 (702) 597-0020 Fax: (702) 597-0095 www.electricalreliability.com

Electrical Reliability Services 610 Executive Campus Dr. Westerville, OH 43082 (877) 468-6384 Fax: (614) 410-8420 info@electricalreliability.com www.electricalreliability.com

NETA ACCREDITED COMPANIES

Electrical Testing, Inc.

2671 Cedartown Hwy Rome, Ga 30161 (706) 234-7623 Fax: (706) 236-9028

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Steve C. Dodd Sr.

Electrical Testing Solutions

2909 Green Hill Ct. Oshkosh, WI 54904 (920) 420-2986 Fax: (920) 235-7131 tmachado@electricaltestingsolutions.com www.electricaltestingsolutions.com Tito Machado

Elemco Services, Inc. 228 Merrick Rd. Lynbrook, NY 11563 (631) 589-6343 Fax: (631) 589-6670 BobW@elemco.com www.elemco.com

Robert J. White

Grubb Emgineering, Inc.

3128 Sidney Brooks San Antonio, Tx 78235 (210) 658-7250 Fax: (210) 658-9805 bobby@grubbengineering.com www.grubbengineering.com

Robert D. Grubb Jr.

Hampton Tedder Technical Services 4571 State St. Montclair, CA 91763 (909) 628-1256 x214 Fax: (909) 628-6375 matt.tedder@hamptontedder.com www.hamptontedder.com

Matt Tedder

Hampton Tedder Technical Services 4920 Alto Ave. Las Vegas, NV 89115 (702) 452-9200 Fax: (702) 453-5412 www.hamptontedder.com

Roger Cates

Hampton Tedder Technical Services 3747 West Roanoke Ave. (480) 967-7765 Fax: (480) 967-7762 www.hamptontedder.com

Harford Electrical Testing Co., Inc. 1108 Clayton Rd. Joppa, MD 21085 (410) 679-4477 Fax: (410) 679-0800 harfordtesting@aol.com

Vincent Biondino

High Energy Electrical Testing, Inc. 2119 Orien Rd. Toms River, NJ 08755-1366 (732) 286-4088 Fax: (732) 286-4086 hinrg@comcast.net www.highenergyelectric.com

James P. Ratshin

High Voltage Maintenance Corp. 24 Walpole Park South Dr. Walpole, MA 02081 (508) 668-9205 www.hvmcorp.com

High Voltage Maintenance Corp. 941 Busse Rd. Elk Grove Village, Il 60007 (847) 228-9595 www.hvmcorp.com

High Voltage Maintenance Corp. 7200 Industrial Park Blvd. Mentor, OH 44060 (440) 951-2706 Fax: (440) 951-6798 www.hvmcorp.com

High Voltage Maintenance Corp. 3000 S. Calhoun Rd. New Berlin, WI 53151 (262) 784-3660 Fax: (262) 784-5124 www.hvmcorp.com

High Voltage Maintenance Corp. 8320 Brookville Rd. #E Indianapolis, IN 46239 (317) 322-2055 Fax: (317) 322-2056 www.hvmcorp.com

High Voltage Maintenance Corp. 1250 Broadway, Ste. 2300 New York, NY 10001 (718) 239-0359 www.hvmcorp.com

High Voltage Maintenance Corp.

355 Vista Park Dr. Pittsburgh, PA 15205-1206 (412) 747-0550 Fax: (412) 747-0554 www.hvmcorp.com

High Voltage Maintenance Corp. 150 North Plains Industrial Rd. Wallingford, CT 06492 (203) 949-2650 Fax: (203) 949-2646 www.hvmcorp.com

High Voltage Maintenance Corp. 9305 Gerwig Ln., Ste. B Columbia, MD 21046 (410) 309-5970 Fax: (410) 309-0220 www.hvmcorp.com

High Voltage Maintenance Corp. 24371 Catherine Industrial Dr. Ste. 207 Novi, MI 48375 (248) 305-5596 Fax: (248) 305-5579 www.hvmcorp.com

High Voltage Maintenance Corp. 5100 Energy Dr. Dayton, OH 45414 (937) 278-0811 Fax: (937) 278-7791 www.hvmcorp.com

HMT, Inc.

6268 Route 31 Cicero, NY 13039 (315) 699-5563 Fax: (315) 699-5911 jpertgen@hmt-electric.com www.hmt-electric.com

John Pertgen

Industrial Electric Testing, Inc. 11321 West Distribution Ave. Jacksonville, FL 32256 (904) 260-8378 Fax: (904) 260-0737 gbenzenberg@bellsouth.net www.industrialelectrictesting.com

Gary Benzenberg

Industrial Electric Testing, Inc. 201 NW 1st Ave. Hallandale, FL 33009-4029 (954) 456-7020 www.industrialelectrictesting.com

Industrial Electronics Group P.O. Box 1870 850369 Highway 17 South Yulee, FL 32041 (904) 225-9529 Fax: (904) 225-0834 butch@industrialgroups.com www.industrialgroups.com

Butch E. Teal

Industrial Tests, Inc. 4021 Alvis Ct., Ste. 1 Rocklin, CA 95677 (916) 296-1200 Fax: (916) 632-0300 greg@indtests.com www.industrialtests.com

Greg Poole

Infra-Red Building and Power Service 152 Centre St. Holbrook, MA 02343-1011 (781) 767-0888 Fax: (781) 767-3462 tom.mcdonald@infraredbps.net www.infraredbps.com

Thomas McDonald Sr.

M&L Power Systems, Inc. 109 White Oak Ln., Ste. 82 Old Bridge, NJ 08857 (732) 679-1800 Fax: (732) 679-9326 dan@mlpower.com www.mlpower.com

Darshan Arora

Magna Electric Corporation 1033 Kearns Crescent, Box 995 Regina, SK S4P 3B2

Canada (306) 949-8131 Fax: (306) 522-9181 kheid@magnaelectric.com www.magnaelectric.com

Kerry Heid

Magna Electric Corporation 3430 25th St. NE Calgary, AB T1Y 6C1 Canada (403) 769-9300 Fax: (403)769-9369 ppetrie@magnaelectric.com www.magnaelectric.com

Pat Petrie

Magna Electric Corporation 851-58th St. East Saskatoon, SK S7K 6X5 Canada (306) 955-8131 x 5 Fax: (306) 955-9181 www.magnaelectric.com

Luis Wilson

Magna Electric Corporation 1375 Church Ave. Winnipeg, MB R2X 2Y7 Canada (204) 925-4022 Fax: (204) 925-4021 cbrandt@magnaelectric.com www.magnaelectric.com

Curtis Brandt

Magna IV Engineering 4103 - 97th St., N.W. Edmonton, AB T6E 6E9 Canada (780) 462-3111 Fax: (780) 462-9799 jwentzell@magnaiv.com www.magnaiv.com

Jereme Wentzell

Magna IV Engineering Unit 10, 10672- 46 St. S.E. Calgary, AB T2C 1G1 Canada (403) 723-0575 Fax: (403) 723-0580 info.calgary@magnaiv.com Jereme Wentzell

Magna IV Engineering 8219D Fraser Ave. Fort McMurray, AB T9H 0A2 Canada (780) 791-3122 Fax: (780) 791-3159 info.fmcmurray@magnaiv.com Jereme Wentzell

Magna IV Engineering

96 Inverness Dr. East, Unit R Englewood, CO 80112 (303) 799-1273 Fax: (303) 790-4816 info.denver@magnaiv.com

Jereme Wentzell

Magna IV Engineering

Oficina 1407 Torre Norte 481 Nueva Tajamar Las Condes, Region Metropolitana 7550099 Chile +(56) 9-9-517-4642 info.chile@magnaiv.com Jereme Wentzell

Magna IV Engineering 1040 Winnipeg St. Regina , SK S4R 8P8 Canada (306) 504-6501 Fax: (306) 729-4897 info.regina@magnaiv.com

Jereme Wentzell

National Field Services 649 Franklin St. Lewisville, TX 75057 (972) 420-0157 www.natlfield.com

Eric Beckman

Nationwide Electrical Testing, Inc. 6050 Southard Trace Cumming, GA 30040 (770) 667-1875 Fax: (770) 667-6578 Shashi@N-E-T-Inc.com www.n-e-t-inc.com

Shashikant B. Bagle

North Central Electric, Inc. 69 Midway Ave. Hulmeville, PA 19047-5827 (215) 945-7632 Fax: (215) 945-6362 ncetest@aol.com

Robert Messina

Northern Electrical Testing, Inc. 1991 Woodslee Dr. Troy, MI 48083-2236 (248) 689-8980 Fax: (248) 689-3418 ldetterman@northerntesting.com www.northerntesting.com

Lyle Detterman

Orbis Engineering Field Services Ltd. #300, 9404 - 41st Ave. Edmonton, AB T6E 6G8 Canada (780) 988-1455 Fax: (780) 988-0191 lorne@orbisengineering.net www.orbisengineering.net Lorne Gara

Pacific Power Testing, Inc. 14280 Doolittle Dr. San Leandro, CA 94577 (510) 351-8811 Fax: (510) 351-6655 steve@pacificpowertesting.com www.pacificpowertesting.com

Steve Emmert

Pacific Powertech, Inc. #110, 2071 Kingsway Ave. Port Coquitlam, BC V3C 1T2 Canada (604) 944-6697 Fax: (604) 944-1271 chite@pacificpowertech.ca www.magnaiv.ca

Cameron Hite

NETA ACCREDITED COMPANIES

Phasor Engineering

Sabaneta Industrial Park #216 Mercedita, PR 715 Puerto Rico (787) 844-9366 Fax: (787) 841-6385 rcastro@phasorinc.com

Rafael Castro

Potomac Testing, Inc. 1610 Professional Blvd., Ste. A Crofton, MD 21114 (301) 352-1930 Fax: (301) 352-1936 kbassett@potomactesting.com www.potomactesting.com

Ken Bassett

Potomac Testing, Inc. 11179 Hopson Rd., Ste. 5 Ashland, VA 23005 (804) 798-7334 Fax: (804) 798-7456 www.potomactesting.com

Power & Generation Testing, Inc. 480 Cave Rd. Nashville, TN 37210 (615) 882-9455 Fax: (615) 882-9591 mose@pgti.net www.pgti.net

Mose Ramieh

Power Engineering Services, Inc. 9179 Shadow Creek Lane Converse, TX 78109 (210) 590-4936 Fax: (210) 590-6214 engelke@pe-svcs.com www.pe-svcs.com

Miles R. Engelke

POWER PLUS Engineering, Inc. 46575 Magallan Dr. Novi, MI 48377 (248) 344-0200 Fax: (248) 305-9105 smancuso@epowerplus.com www.epowerplus.com

Salvatore Mancuso

Power Products & Solutions, Inc. 12465 Grey Commercial Rd. Midland, NC 28107 (704) 573-0420 x12 Fax: (704) 573-3693 ralph.patterson@powerproducts.biz www.powerproducts.biz

Ralph Patterson

Power Products & Solutions, Inc. 13 Jenkins Ct. Mauldin, SC 29662 Fax: (800) 328-7382 ralph.patterson@powerproducts.biz www.powerproducts.biz

Raymond Pesaturo

Power Services, LLC P.O. Box 750066, 998 Dimco Way Centerville, OH 45475 (937) 439-9660 Fax: (937) 439-9611 mkbeucler@aol.com

Mark Beucler

Power Solutions Group, Ltd. 425 W. Kerr Rd. Tipp City, OH 45371 (937) 506-8444 Fax: (937) 506-8434 bwilloughby@powersolutionsgroup.com www.powersolutionsgroup.com

Barry Willoughby

Power Solutions Group, Ltd. 135 Old School House Rd. Piedmont, SC 29673 (864) 845-1084 Fax:: (864) 845-1085 fcrawford@powersolutionsgroup.com www.powersolutionsgroup.com

Frank Crawford

Power Solutions Group, Ltd. 670 Lakeview Plaza Blvd. Columbus, OH 43085 (614) 310-8018 sspohn@powersolutionsgroup.com www.powersolutionsgroup.com

Stuart Spohn

Power Systems Testing Co. 4688 W. Jennifer Ave., Ste. 108 Fresno, CA 93722 (559) 275-2171 ext 15 Fax: (559) 275-6556 dave@pstcpower.com www.powersystemstesting.com

David Huffman

Power Systems Testing Co. 600 S. Grand Ave., Ste. 113 Santa Ana, CA 92705-4152 (714) 542-6089 Fax: (714) 542-0737 www.powersystemstesting.com

Power Systems Testing Co. 2267 Claremont Ct. Hayward, CA 94545-5001 (510) 783-5096 Fax: (510) 732-9287 www.powersystemstesting.com

Power Test, Inc. 2200 Highway 49 Harrisburg, NC 28075 (704) 200-8311 Fax: (704) 455-7909 rich@powertestinc.com www.powertestinc.com

Richard Walker

POWER Testing and Energization, Inc. 14006 NW 3rd Ct., Ste. 101 Vancouver, WA 98685 (360) 576-4826 Fax: (360) 576-7182 chris.zavadlov@powerte.com www.powerte.com

POWER Testing and Energization, Inc. 731 E. Ball Rd., Ste. 100 Anaheim, CA 92805 (714) 507-2702

http://www.powerte.com

POWER Testing and Energization, Inc. 22035 70th Ave. South Kent, WA 98032 (253) 872-7747 www.powerte.com

Powertech Services, Inc. 4095 South Dye Rd. Swartz Creek, MI 48473-1570 (810) 720-2280 Fax: (810) 720-2283 jbrown@powertechservices.com www.powertechservices.com

Jean A. Brown

Precision Testing Group 18590 Wedemeyer Rd. Kiowa, CO 80117 (303) 621-2776 Fax: (303) 621-2573 glenn@precisiontestinggroup.com

Glenn Stuckey

PRIT Service, Inc. 112 Industrial Dr., P.O. Box 606 Minooka, IL 60447 (815) 467-5577 Fax: (815) 467-5883

Rod.Hageman@pritserviceinc.com www.pritserviceinc.com

Rod Hageman

Reuter & Hanney, Inc. 149 Railroad Dr. Northampton Industrial Park Ivyland, PA 18974 (215) 364-5333 Fax: (215) 364-5365 mikereuter@reuterhanney.com www.reuterhanney.com

Michael Reuter

Reuter & Hanney, Inc. 4270-I Henninger Ct. Chantilly, VA 20151 (703) 263-7163 Fax: 703-263-1478 www.reuterhanney.com

Reuter & Hanney, Inc.

11620 Crossroads Circle, Suites D-E Middle River, MD 21220 (410) 344-0300 Fax: (410) 335-4389 www.reuterhanney.com

Michael Jester

REV Engineering, LTD 3236 - 50 Ave. SE Calgary, AB T2B 3A3 Canada (403) 287-0156 Fax: (403) 287-0198 rdavidson@reveng.ca www.reveng.ca

Roland Nicholas Davidson, IV

NETA ACCREDITED COMPANIES

Scott Testing Inc. 1698 5th St. Ewing, NJ 08638 (609) 882-2400 Fax: (609) 882-5660

rsorbello@scotttesting.com www.scotttesting.com

Russ Sorbello

Shermco Industries

2425 E. Pioneer Dr. Irving, TX 75061 (972) 793-5523 Fax: (972) 793-5542 rwidup@shermco.com www.shermco.com

Ron Widup

Shermco Industries 1705 Hur Industrial Blvd. Cedar Park, TX 78613 (512) 259-3060 Fax: (512) 258-5571 kewing@shermco.com www.shermco.com

Kevin Ewing

Shermco Industries 33002 FM 2004 Angleton, TX 77515 (979) 848-1406 Fax: (979) 848-0012 mfrederick@shermco.com www.shermco.com

Malcom Frederick

Shermco Industries 1357 N. 108th E. Ave. Tulsa, OK 74116 (918) 234-2300 jharrison@shermco.com www.shermco.com

Jim Harrison

Shermco Industries

777 10th St. Marion, IA 52302 (319) 377-3377 Fax: (319) 377-3399 Lhamrick@shermco.com www.shermco.com

Lynn Hamrick

Shermco Industries 2100 Dixon St., Ste. C Des Moines, IA 50316 Fax: (515) 263-8482 DesMoines@shermco.com www.shermco.com

Lynn Hamrick

Shermco Industries Boulevard Saint-Michel 47 1040 Brussels Brussels, Belgium

+32 (0)2 400 00 54 Fax: +32 (0)2 400 00 32 cperry@shermco.com www.shermco.com

Chris Perry

Sigma Six Solutions, Inc. 2200 West Valley Hwy., Ste. 100 Auburn, WA 98001 (253) 333-9730 Fax: (253) 859-5382 jwhite@sigmasixinc.com www.sigmasixinc.com

John White

Southern New England Electrical Testing, LLC 3 Buel St., Unit 2 Wallingford, CT 06492 (203) 269-8778 Fax: (203) 269-8775 dave.asplund@sneet.org www.sneet.org

David Asplund, Sr.

Southwest Energy Systems, LLC 2231 East Jones Ave., Ste. A (602) 438-7500 Fax: (602) 438-7501 bob.sheppard@southwestenergysystems.com www.southwestenergysystems.com

Robert Sheppard

Taurus Power & Controls, Inc. 9999 SW Avery St. Tualatin, OR 97062-9517 (503) 692-9004 Fax: (503) 692-9273 robtaurus@tauruspower.com www.tauruspower.com

Rob Bulfinch

Taurus Power & Controls, Inc. 6617 S. 193rd Place, Ste. P104 Kent, WA 98032 (425) 656-4170 Fax: (425) 656-4172 jiml@tauruspower.com www.taruspower.com

Jim Lightner

Three-C Electrical Co., Inc. 190 Pleasant St. Ashland, MA 01721 (508) 881-3911 Fax: (508) 881-4814 jim@three-c.com www.three-c.com

Jim Cialdea

Three-C Electrical Co., Inc. 79 Leighton Rd., Ste. 9 Augusta, ME 04330 (800) 649-6314 Fax: (207) 782-0162 jim@three-c.com www.three-c.com Jim Cialdea

Tidal Power Services, LLC 4202 Chance Lane Rosharon, TX 77583 (281) 710-9150 Fax: (713) 583-1216 monty.janak@tidalpowerservices.com www.tidalpowerservices.com

Monty C. Janak

Tidal Power Services, LLC 18786 Lake Harbor Lane Prairieville, LA 70769 (225) 223-5677 Fax: (225) 208-1013 www.tidalpowerservices.com

Darryn Kimbrough

Tony Demaria Electric, Inc. 131 West F St. Wilmington, CA 90744 (310) 816-3130 x 111 Fax: (310) 549-9747 tde@tdeinc.com www.tdeinc.com

Anthony Demaria

Trace Electrical Services & Testing, LLC 293 Whitehead Rd. Hamilton, NJ 08619 (609) 588-8666 Fax: (609) 588-8667 jvasta@tracetesting.com www.tracetesting.com

Joseph Vasta

Utilities Instrumentation Service, Inc. PO Box 981123 Ypsilanti, MI 48198-1123 (734) 482-1450 (14) Fax: (734) 482-0035 GEWalls@UISCorp.com www.uiscorp.com

Gary E. Walls

Utility Service Corporation

4614 Commercial Dr. NW Huntsville, AL 35816-2201 (256) 837-8400 Fax: (256) 837-8403

apeterson@utilserv.com www.utilserv.com

Alan D. Peterson

Western Electrical Services

14311 29th St. East Sumner , WA 98390 (253) 891-1995 Fax: (253) 891-1511 dhook@westernelectricalservices.com www.westernelectricalservices.com

Daniel Hook

Western Electrical Services

3676 W. California Ave. Bldg. C, Ste. 106 Salt Lake City, UT 84104 (253) 891-1995 dhook@westernelectricalservices.com www.westernelectricalservices.com

Daniel Hook

Western Electrical Services

5680 South 32nd St. (253) 891-1995 dhook@westernelectricalservices.com www.westernelectricalservices.com

Daniel Hook

Western Electrical Services

4510 NE 68th Dr., Ste. 122 Vancouver, WA 98661 (253) 891-1995 Fax: (253) 891-1511

dhook@westernelectricalservices.com www.westernelectricalservices.com

Daniel Hook

NETAhas been connecting designers, speci ers, architects and users of electrical power equipment and systems with independent, third-party electrical testing companiessince 1972.

NETAAccredited Companies test thecompletesystem in accordance withindustry codes and standards toprovide accurate test reports you can count on everytime.

This issue’s advertisers are identified below. Please thank these advertises by telling them you saw their advertisement in YOUR magazine –NETA World.

INDEPENDENT NETA

My Dad tests transformers

... and with the PDL 650 system he can always find the location of a failure

With the new PDL 650 Dad can track partial discharge (PD) in the transformer without opening it up. The PDL 650 creates a 3D-representation of a failure based on acoustic signals emitted by partial discharge.

When used together with the MPD 600 even electrical and UHF measurements can act as additional signal inputs.

By combining the data of electrical and acoustic signals Dad can examine transformers faster and more effectively than ever before.

Dad can generate a comprehensive report of a measurement with the click of a mouse. This way he can get a precise overview of all the transformers that he´s tested.

Visit us online and find out how the PDL 650 and MPD 600 can work for you!