Informing the electrical industry for over 140 years
May 2017 Volume 250 | No5 www.electricalreview.co.uk
Test & measurement Zero unplanned downtime – dream or reality?
Arc ﬂash AC and DC – electrical hazards
Voltage optimisation Perfecting the electricity mix
CONTENTS | 3
04 NEWS Select to launch new SQA course
08 GOSSAGE Gossage:gossip
10 TEST & MEASUREMENT Zero unplanned downtime – dream or reality?
27 SWITCHGEAR &SUBSTATION TECHNOLOGY Witness the FITNESS for digital substations
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22 FACTORY AUTOMATION Collaborative robots and worker safety? It can be done
32 ARC FLASH AC and DC - electrical hazards
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VOLTAGE OPIMISATION Comparison of voltage optimisation technologies
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4 | NEWS
Contrac Lighting announces merger with High Technology Lighting UK lighting providers, Contrac Lighting and High Technology Lighting, have announced their plans to merge businesses; creating one larger, more secure, lighting manufacturer. Both businesses will now operate out of Contrac’s facility in Goole, East Yorkshire. This will allow High Technology to beneﬁt from a dedicated in-house manufacturing process, meaning not only a more efﬁciently delivered and competitive range of standard luminaires, but also the capability to easily produce bespoke solutions. “Contrac Lighting has always had a close working relationship with High Technology Lighting so bringing the two companies together under one banner was always an aspiration we held, so myself and Kelvin are delighted that this has now happened and are excited about the future with Graham and Thomas on board.” -
Engineering specialist reports strong start to 2017 with significant new investment Engineering expert Teddington is reporting a strong start to 2017 with new investment promising even greater efﬁciency. The company, which specialises in electronics, critical systems, control panel technology, appliance controls and valve fabrication for sectors such as defence, aerospace, energy and transport, recently took delivery of three new pieces of equipment at its manufacturing centre in Cornwall. Among them was a Pillarhouse Pilot 29 selective soldering machine. James Henderson, managing director of Teddington Group, said the state of the art machinery would lead to even greater efﬁciency in the manufacturing process, helping to keep prices low despite rising import costs. “The threat of Brexit has deﬁnitely made it a challenging start to the year and margins are certainly a lot tighter, but interestingly we are still incredibly busy,” he said. “Critical to our business in the coming months – and to others in the manufac-
turing sector – will be the ability to ﬁnd smarter ways to design, develop and deliver solutions for our clients. “New products will be key. The thirst for innovation has not diminished. We have seen the largest growth in energy saving products, while monitoring and information gathering systems and control devices are also in demand.” Teddington has also invested in a Nordson Yestech BX12 optical inspection unit that uses multiple cameras and state of art image recognition to check the quality of a circuit board to ensure all components have been positioned and soldered correctly.
2017 target should mean free lamp recycling for all businesses The government recently announced the 2017 waste lamp recycling target. This is great news for businesses – most should be able to get their waste lamps recycled free of charge. The Waste Electrical and Electronic Equipment (WEEE) regulations require manufacturers to fund the recycling of WEEE – including ﬂuorescent lamps. Each year, the Government sets a target for the tonnage of recycling that manufacturers must fund, through their WEEE schemes. At the end of March 2017, the Government announced that the 2017 UK lamp recycling target was 6132 tonnes. The Government chose this target as it is the total tonnage recycled in 2016. By setting a target in 2017 at the same level of actual recycling undertaken in 2016, WEEE schemes will need to ﬁnance virtually all lamp recycling that takes place in 2017. This is great news for businesses with waste lamps that need to be recycled. In virtually all cases, particularly where they hold larger quantities, they should not need to pay anything. To access the free service, it should simply be a matter of calling a WEEE scheme, such as Recolight, Electrical Review | May 2017
to ask for the service. Most good schemes, that have lighting producer members, should be able to make the necessary arrangements. That service may well include a free container, free collection, and free recycling. Electrical contractors, wholesalers, lighting maintenance companies, and facilities maintenance companies should all be able to access the same free service.
As the roll-out of LED integrated luminaires continues, it is vital to ensure that the waste ﬂuorescent lamps that arise are properly recycled. It would be tragic if a move to more sustainable LED lighting was not underpinned by ensuring that the waste ﬂuorescents are properly recycled. Nigel Harvey is CEO of Recolight, a notfor-proﬁt lighting WEEE scheme.
NEWS | 5
Learners encouraged to practice electrical installation with specialist Temporary power distribution specialist ide Systems recently invited 40 learners to undergo work experience at its Cannock and Burntwood site. Learners that were enrolled on any level of the electrical installation course at South Staffordshire College in September, 2016, have had the opportunity to put their taught knowledge into practice at the company, with learners ultimately assisting the assembly of electrical distribution panels. Working alongside ide Systems’ skilled engineers, learners were taught about all aspects of the electrical industry, including equipment, health and safety practices and how to approach different emergency situations. After being briefed on the processes and practices, students assisted in building and assembling electrical distribution panels. Learners participating in the vocational programme are set to complete 30 hours at either ide Systems’ Cannock or Burntwood site. With most of the learners aged between 16 and 18, ide Systems has tailored the programme so that everyone involved can allocate their hours across the year to complement their academic studies. “We pride ourselves in providing a ﬂexible and exciting learning opportunity for anyone interested in a career in electrical installation,” explained Matt Collins, business development manager of ide Systems. “I attended the college as a mature student and was fortunate to ﬁnd employment quickly and progress into management. Still having close links to the college, we wanted to form a partnership that would offer those interested in electrical installation, a real opportunity to understand the industry and boost their conﬁdence when looking for work.
“As a company, ide Systems is constantly expanding and recruiting. As such, the learners demonstrating their talent and practical skills have the opportunity to become a long-term part of the business if a vacancy becomes available.” At a time when the engineering skills shortage is a prominent issue across a number of industrial sectors, ide Systems is investing in the future of electrical engineering by working with institutions to develop the younger work force. The partnership with the South Staffordshire College resulted in ide Systems previously hiring two apprentices on completion of their electrical course, as well as another individual that participated in the work experience programme. “It is every company’s responsibility to
do more to capture the interest of younger people and help them into the profession,” said Collins. “While academic courses teach the theoretical knowledge, practical experience is essential to ensure that those entering the industry have the required skills. The value of apprenticeship and practical learning schemes must be continuously pushed to ensure a positive future for engineering in the UK.” “Both the college and ide Systems have a strong focus on providing young people with actual experience in the industry, which assists them in ﬁnding future employment,” said Julie Bird, employer engagement co-ordinator at South Staffordshire College. teamwork and reliability, as well as all of the technical elements.”
w: www.spec-ltd.com e: firstname.lastname@example.org t: 01924 871 558 SPEC Ltd has recently expanded its services to meet the individual needs and demands of the customer to become a national company with regional presence. With a proven track record of successfully working with many service users from small businesses to large Blue chip multinationals both UK and overseas. Established as a total substation service provider, in the role of control, installation, cabling, operation and maintenance of mains 415/11000/33000 & now 66000 and 132,000 v power networks. To date SPEC Ltd operate and maintain over 2,500 HV connected sites nationwide from its 6 strategic regional offices in Washington, Lancaster, Wakefield, Bromsgrove, Oxford and Aldershot.
Head Office Unit 5 Eagle Point, Telford Way, 41 Industrial Estate, Wakefield, WF2 OXW Fax: +44 (0) 1924 871559
6 | NEWS
MPs conclude core industrial sectors Electrical industry assessment network need prioritising for apprenticeships comes together for NET Centre Conference The organisations responsible for assessing more than 5,000 apprentice electricians each year came together for the NET 2017 Centre Conference. Representatives from NET licensed centres in England, Wales and Northern Ireland attended the one day event, which looked at the changes to the apprenticeship landscape and the impact this has on NET and its centre network. Attendees heard from NET chief executive Carolyn Mason and NET technical development manager Jon Dicken about changes in apprenticeship policy, updates to the AM2 assessment and the infrastructure that supports it, and work underway to develop new assessments for the specialist areas of the electrotechnical industry. Pat Allen, lead employer for the Fire, Emergency and Security Systems (FESS) Employer Group, also spoke about the FESS Apprenticeship Standard and the apprenticeship’s end-point assessment, which NET is currently developing. Carolyn Mason said: “We held this conference to ensure our centres understand how the changes in government policy affect NET, the AM2 and the network of licensed centres that deliver it and to update them on what we’re doing to ensure the assessments we offer ﬁt within those reforms and reﬂect the needs of employers.” “We also wanted to brief them about other assessments we have been asked to develop by employers, for example the FESS end-point assessment, which we’re currently working on, and others for specialist areas of the electrotechnical industry that are developing Apprenticeship Standards.”
Electrical Review | May 2017
A new parliamentary committee report on skills, which urges the government to “prioritise” getting young people to take up apprenticeships in industry sectors with skills shortages, such as electrotechnical, has been backed by the Electrical Contractors’ Association (ECA). According to a recent ECA survey, almost half of electrotechnical businesses (47%) expect to face a skills shortage in 2018.In addition, the report states “there remains a lack of clarity about long-term funding arrangements for non-apprenticeship levy paying employers”. ECA director of employment and skills, Alex Meikle, commented: “It’s widely accepted that engineering disciplines, such as electrotechnical,face an ongoing skills shortage. This threatens to derail broader government efforts to develop a highly skilled, highly paid workforce. “The ECA strongly supports proposals to target apprenticeships towards core industry sectors facing a shortfall. In addition, we urge the government to ensure SMEs have the funding they need to train up the elec-
tricians and engineers of tomorrow.” Last year the ECA provided written evidence to the inquiry, which stated government apprenticeship funding policy “risked... driving investment in short duration, lower value apprenticeships which are easier to deliver”, rather than “technical, longer duration, higher value apprenticeships.” Three ECA representatives gave verbal evidence to the inquiry – including apprentices Niall Watson of Derry Building Services and Charlotte Burton of NG Bailey. The apprentices described how they got into their careers, noting this happened despite receiving limited technical careers advice while at school.
Select to launch new SQA course in electrical safety Select, the campaigning trade body for the electrotechnical industry in Scotland, is to introduce a major new customised course in electrical safety which will relate to the most current aspects of safety awareness in the sector. The new Scottish Qualiﬁcations Authority (SQA) course is in development at the moment and is likely to be launched as a pilot in the third quarter of this year before full introduction. With safety a key concern in the industry, it will be aimed primarily at contractors, as well as managers and personnel within
these ﬁrms who have a responsibility for ensuring safe operations. To be called the Select SQA Customised Award in Electrical Safety, the course will run over two and a half days and will initially be held at Select’s HQ at the Walled Garden outside Edinburgh, though thereafter it will be rolled out across Scotland. Dave Forrester, head of technical services at Select who runs the organisation’s training department, said: “Those involved in safety management want to stay in front of regulation and technical developments.”
8 | GOSSAGE
Consistency is the hobgoblin of little minds
By the time you read this, it seems highly likely prime minister Theresa May will be celebrating nine months in ofﬁce, by intervening overtly in the prices that energy ﬁrms can charge their householders. And receiving congratulations from the tabloid newspapers for doing so. Two simple points are worth bearing in mind. Point one is that during the most recent general election – held just two years ago this month- it was the Labour party, not the Conservative party , that was promoting a policy of interference in the prices that energy companies could charge customers. And it was the Conservative party , cheered on by the tabloid newspapers, that was damning such interventions as economic illiteracy. The second point is that, for fuel bill payers, the most important factor is NOT just the costs being charged per kilowatt hour. Equally important is the number of kilowatt-hours consumed each month. Over the past decade the overall number of kilowatt-hours bought has dropped heavily, by 15.2% in electricity’s case, by 32.8% in that of natural gas. This means the Big Six have been selling much less than they were anticipating. And must therefore have every incentive to maintain revenues up, by keeping kilowatt-hour costs higher than strictly necessary. The law of Supply and Demand at work, prime minister, the law of Supply and Demand.
Gold turns to dust
If only Britain’s BNFL hadn’t sold Westinghouse. Just think of all that nuclear expertise lost: the sort that has just seen the company crash into Chapter 11 bankruptcy administration, with liabilities now up to $9.8bn. Among the many things for which former prime minister Gordon Brown gets deserved ﬂak, getting shot of Westinghouse while he was chancellor deﬁnitely isn’t one of them: sold for $5.4bn in 2006, or more than four times what Britain paid for it. The subsequent tale is horribly familiar in this post-Fukushima world, where mega-nuke safety costs have rocketed: four Toshiba reactors in Georgia and South Carolina are now $10bn over budget and three years late. All this is exacerbated by Westinghouse’s desperate purchase of the US nuclear construction outﬁt Stone & Webster, in an attempt to halt a legal ﬁght over who was to blame for the ballooning costs. There is a lesson for Britain — and it is not the hand-wringing over who will replace Toshiba on the project to build the 3,800MW Moorside plant in Cumbria, a monster even bigger than Hinkley Point C. It is that trying to build massive nuclear power plants are a licence to blow yourself up ﬁnancially. And that is before the soaraway clean-up costs, driven home by the botched £6.1bn contract for 12 Magnox reactors which has seen business secretary Greg Clark publicly grovelling for a ‘defective procurement’ process that meant the deal agreed did not cover the work required. Indeed, Britain’s clean-up bill already stands at £117bn. How many more nuclear disasters before the government ﬁnally wakes up?
Pure and most thoughtful minds Following the passage of the 2008 Climate Change Act, Parliament created the Committee on Climate Change to provide independent advice. Under the chairmanship of former Conservative environment secretary John Gummer (now metamorphosed as Lord Deben), it has sought to ensure that the UK has policies in place that will deliver the ultimate objective – 80% fewer greenhouse gases emitted in 2050 than in 1990. M’Lord Deben has surrounded himself with a board formed of the greatest scientiﬁc minds, drawn from our ﬁnest universities. It has consequently produced a series of excellent, well-researched publications, each intended either to cajole or (less frequently) praise government for staying the course with its carbon reduction policies. The Committee has just broken with precedent, and appointed to its board, not yet another scientist, but a business person. And not any old business person. Dr. Rebecca Heaton, has been appointed for a ﬁve-year term. She will also remain in her existing position as the head of sustainability and policy at Drax in Yorkshire, Environmental groups have condemned the appointment of a senior representative at what they claim is the world’s biggest woodﬁred power station and the UK’s biggest coalﬁred plant and carbon emitter. Dr Doug Parr, Policy Director at Greenpeace UK, said: “It’s surprising that the ﬁrst business appointment to the Committee should come from a sector as controversial as biomass and fossil fuel.” I suspect that, from now onwards, Lord Deben & Co will have to work very hard to ensure they are beyond reproach in transparently examining future technological scenarios, especially on bio-energy and decentralisation, to maximise beneﬁts for the environment.
Welcome to the snake pit Senior ofﬁcials in President Trump’s White House own up to $12.3m in fossil fuel energy company stocks and shares, according to a Center for American Progress (CAP) analysis of White House ﬁnancial disclosure forms. While six members of President Trump’s staff hold a majority of these shares, there are at least a dozen more White House senior employees who have some personal holding in energy stocks, including shares of companies like Exxon Mobil and Chevron. “At best, these ﬁnancial disclosures call into question the extent to which White House staff can be even-handed in their approach to energy and environmental issues. At worst, they illustrate a snake pit of potential ethical violations,” CAP senior campaign manager Claire Moser says. If you thought it was only a perverse ideology that is causing Trump deliberately to scrap every programme concerned with either renewables or energy efﬁciency, and to promote everything to do with fossil fuel consumption, think again. It seems it may have far more to do with lining the pockets of those surrounding him. Electrical Review | May 2017
10 | TEST & MEASUREMENT
Zero unplanned downtime â&#x20AC;&#x201C; dream or reality? %ULWLVK VFLHQFH Ă&#x20AC;FWLRQ ZULWHU $UWKXU & &ODUNH IDPRXVO\ VWDWHG LQ KLV WKLUG ODZ RI SUHGLFWLRQ WKDW Â´DQ\ VXIĂ&#x20AC;FLHQWO\ DGYDQFHG WHFKQRORJ\ LV LQGLVWLQJXLVKDEOH IURP PDJLF Âľ 3UHGLFWLYH DQDO\WLFV LV QRW TXLWH PDJLF EXW LW FRXOG PDNH D ZRUOG RI GLIIHUHQFH IRU FRPSDQLHV ZKR ZDQW WR VDYH FRVWV DQG LPSURYH HIĂ&#x20AC;FLHQF\ +HUH /HUR\ 6SHQFH PDQDJHU IRU WKH $PHULFDV DW LQGXVWULDO HTXLSPHQW VXSSOLHU (8 $XWRPDWLRQ GLVFXVVHV KRZ PDQXIDFWXUHUV FDQ XVH SUHGLFWLYH DQDO\WLFV WR PDQDJH DVVHWV DQG PLQLPLVH GRZQWLPH
ost manufacturers have been using predictive analytics for years in the form of spreadsheets and manual data entry. Although useful, these methods were subject to operator assumptions and human error. As the number of sensors on the factory ďŹ&#x201A;oor increases, data gathering becomes automated and data sets are easier to analyse. New predictive analytics techniques also signiďŹ cantly improve data accuracy. Engineers can use these data sets for predictive maintenance purposes to determine the condition of in-service equipment and identify when it will need to be repaired or replaced. Predictive analytics is able to compare real-time machine data gathered from sensors to a history of machine failure. It uses complex algorithms to spot behavioural patterns before a breakdown. By combining sensor technology and big data analytics, manufacturers can minimise equipment failure. Knowing that a motor or drive is likely to break soon means the manufacturer can repair it or order a replacement before a breakdown occurs. It also allows manufacturers to schedule maintenance work for a convenient time,
Electrical Review | May 2017
instead of shutting down production as and when breakdowns happen. Predictive maintenance not only minimises downtime, it also gives maintenance engineers and plant managers peace of mind. It frees up the time of maintenance staff, so that they can deal with tasks that are more valuable to the business. In the near future, it is conceivable that a smart production line could order spare parts automatically when necessary, with minimal human intervention.
A slight redesign could reduce the risk of failure BEYOND PREDICTIVE MAINTENANCE The real beneďŹ t of predictive maintenance lies in the hidden potential of data. By analysing historical data and identifying machine or part breakdown patterns a manufacturer could easily identify weak points in their production line and implement measures to address these ďŹ&#x201A;aws.
For example, if there is an electric motor that breaks regularly on a production line, the plant manager could look at the historical data gathered from the motor and compare it to environmental data to identify the most likely cause of failure, such as excessive heat, power supply issues, humidity or vibration. A slight redesign could help reduce the likelihood of these factors leading to failure. An experienced engineer would also be able to identify the causes of constant equipment failure and suggest changes, but predictive maintenance makes the process much easier. Perhaps the most exciting application of predictive analytics lies outside the factory doors. By integrating predictive analytics into their products, manufacturers can turn the technology into an add-on service. The self-diagnosing and self-maintaining production line is still a few years away, but it is becoming more of a reality as predictive analytics technology becomes more widely available. It all comes down to Arthur C Clarkeâ&#x20AC;&#x2122;s second law of prediction, which states â&#x20AC;&#x153;the only way of discovering the limits of the possible is to venture into the impossible.â&#x20AC;?
TEST & MEASUREMENT | 11
12 | TEST & MEASUREMENT
A background on the noise ďŹ&#x201A;oor 7KH QRLVH Ă RRU RI DQ\ PHDVXUHPHQW V\VWHP FDQ EH GHĂ&#x20AC;QHG DV WKH VXP RI DOO XQZDQWHG DXGLR VLJQDOV RXWVLGH RI WKH VLJQDO WKDW LV EHLQJ PRQLWRUHG E\ DQ H[SHULPHQW RU WHVW 7KH QRLVH Ă RRU UHSUHVHQWV D ZLGH YDULHW\ RI VLJQDO RULJLQ SRLQWV LQFOXGLQJ DWPRVSKHULF QRLVH DQG PRUH 7KH KLJKHU WKH QRLVH Ă RRU WKH PRUH GLIĂ&#x20AC;FXOW LW LV IRU D PHDVXUHPHQW GHYLFH WR LVRODWH DQ LQGLYLGXDO VLJQDO
oise ďŹ&#x201A;oors that are high enough can drastically reduce the viability of experimental results. It is always in the best interests of the experimenter to lower the noise ďŹ&#x201A;oor as much as possible either through artiďŹ cial means or by seeking out conditions that correspond to the lowest noise ďŹ&#x201A;oor possible. The noise floor began to matter to
Electrical Review | May 2017
humans once sound recordings became a reality in 1857. Ă&#x2030;douard-LĂŠon Scott de Martinville recorded the first sound on a device called the â&#x20AC;&#x153;phonautograph,â&#x20AC;? a machine with the ability to transcribe a wave of sound into a line that was drawn on glass or paper. This preceded Alexander Graham Bell and the first iteration of the telephone in 1875. The first sound transmitted through radio
came in 1900, a feat accomplished by Reginald Aubrey Fessenden. All of these signals included a noise floor. Wherever an audio signal is measured or transcribed, noise is also introduced into the measurement. Acoustic geologist Gordon Hempton has concluded after years of experimentation that there is literally no place on earth that is not affected by noise, meaning that every unaffected captured
14 | TEST & MEASUREMENT
audio signal will contain some measure of unwanted background noise. This ﬁnding was repeated by Bernie Krause, a bioacoustics expert. Noise originates from the beginning of the universe and is known as cosmic noise or cosmic background noise. This cosmic noise is generated through the constant movement of weighted bodies in the universe. Contrary to popular belief, sound does not actually need air to travel - when the universe was smaller and denser, sound easily travelled through the “vacuum” of space. Atmospheric noise is relatively highfrequency background radio noise that comes from natural processes within the atmosphere. The most common process
Electrical Review | May 2017
causing this noise is the lightning flash - 3.5 million of these events occur in a single day (40 per second). Atmospheric noise usually occurs within the 90-
Incidental noise is an umbrella term 110 kHz range and may cause sound recording instruments to vibrate so much that they cannot properly record the experiment signal. Incidental noise is an umbrella term
that represents all of the background noise that comes from far off events such as a plane flying by. Many of these events are so far off and the sound waves so small that humans cannot perceive them, but they do affect the sound waves that occur in measurements. Finally, the noise that comes from the measurement system itself comprises a major component of the noise floor of sound measurements. As systems measure objects, they give off heat, radiation and cause friction between moving parts, all of which generates noise and adds to the noise floor. Depending on the measurement device that you use, you may be able to hear this noise as it is created.
TEST & MEASUREMENT | 17
Voltage sources for cable fault detection compared Is there really a need to carry out anything other than cursory tests on newly installed HV cables? After all, installation techniques are well established and contractors are familiar with what’s needed. Surely satisfactory performance of new cables can be almost taken for granted? The answer to this question is an emphatic NO!
nfortunately, faults are routinely found on newly installed cables. An example, admittedly an extreme case, concerns an 11 km cable installed to serve a wind farm. The installation work had been carried out by four different contractors, and all had simply laid the cable in the ground with no sand backﬁll. On testing, this cable was found to have between 10 and 20 sheath faults per kilometre! So let’s be very clear from the outset that exhaustive testing of new cables isn’t something that’s optional – it’s an absolute necessity! But what form of testing should be employed? In answering this question, we can start by saying that DC testing is generally acknowledged to be of limited value in detecting typical problems relating to poor workmanship. Experience shows that VLF testing is a much better option. It is, however, important to be clear VLF testing will undoubtedly uncover major workmanship problems but, depending on the voltage source used – VLF, resonant or 50/60 Hz –
undetected problems may sometimes remain. It is nevertheless reasonable to say that if a VLF test shows a cable to be fault-free, it’s safe to energise, although there may still be undiscovered incipient problems that could shorten the cable’s service life and lead to premature failure. The most reliable way to uncover these “hidden” problems is with partial discharge (PD) analysis. Once again, it’s necessary to sound a note of caution. No test technique is guaranteed to ﬁnd every conceivable cable problem. PD analysis is by far the most dependable technique and it will uncover almost all workmanship related problems, but it will not, for example, ﬁnd high contact resistance faults within new joints that will lead to in-service thermal breakdown, What it will ﬁnd is faults like poor cable preparation, most types of poor jointing technique and exotic faults like insect damage. In summary, PD analysis is a reliable, easyto-implement method of quality control for newly installed cables. It makes it possible to check on the performance of service
contractors, to check on the quality of work produced by the cable owner’s own staff and to signiﬁcantly increase the reliability and availability of the network. As well as quality control, PD analysis is also invaluable for post-repair testing to check that the repair has been carried out satisfactorily and that the cable has not suffered further damage as a result of, for example, high fault currents. Finally, PD analysis is an excellent way of monitoring the condition of cables that have been in service for some time, to detect possible deterioration of the insulation and cable accessories. Of course, when considering PD analysis the next question is what voltage waveform should be used to energise the cable under test? Several internationally accepted and widely used options are available, and each has its own pros and cons. Let’s take a look at the three principal options, and examine their advantages and disadvantages.
VLF SINUSOIDAL AT 0.1 HZ This has the major advantage that it can
TEST & MEASUREMENT | 19
also be used for Tan Delta measurements. Its biggest drawback, however, is that the PD characteristics obtained from testing with this waveform are not directly comparable with the behaviour of the cable at power frequency, which makes it difﬁcult to relate the results to the future in-service performance and reliability of the cable. There is also a minor possibility of the cable being damaged by the test, though this only a signiﬁcant risk with old water-treed cables.
VLF COSINE-RECTANGULAR (CR) AT 0.1 HZ For a given physical size and weight, test sets using this waveform have a much higher testing capacity than their sinusoidal counterparts. This means that they can test longer cables and that, in many cases, all three phases can be energised and tested in parallel. Another very signiﬁcant advantage is that the PD results are directly comparable with those that would be obtained at power frequency, so the test gives a very good indication of the likely in-service behaviour of the cable. The biggest drawback of VLF CR testing is that this waveform cannot be used to perform Tan Delta testing. As with sinusoidal testing, there is a small risk of cable damage during testing but, once again, this risk is only signiﬁcant with old water-treed cables.
DAMPED AC (DAC) As with VLF CR testing, DAC test sets have a high test capacity for their size, allowing long cables to be tested, as well as three-phase cables with the phases connected in parallel. DAC testing also delivers PD results that are directly comparable with those that would be obtained at power frequency and it has the added beneﬁt that it is very unlikely to cause cable damage as the test voltage is only applied to the cable for a short time. The drawback of using the DAC waveform is that, as is the case with the VLF CR waveform, no Tan Delta testing can be performed. Because each of these voltage waveforms has its own beneﬁts and shortcomings, it’s clear that it would be very useful to be able to select the best waveform to use on a case-by-case basis, according to the needs of the particular application. It’s equally clear, however, that purchasing, maintaining and transporting separate test sets for each waveform is an option that’s far from being attractive. What engineers really need is a test set that
offers a choice to test voltage waveforms in one device, that allows standards-compliant VLF testing at 0.1 Hz, that automatically evaluates and interprets measurement data, and that incorporates a time-saving voltage withstand testing with accompanying diagnostic measurements. And it is to meet these needs that Megger has developed its new TDM series of cable test sets. These innovative test sets combine cable testing, cable diagnostics and sheath testing in a single device. They allow standardscompliant VLF testing at 0.1 Hz of cables with capacities of up to 5.5 μF at 36 kVrms, and up to 10 μF at 18 kVrms. In addition, they have integrated Tan-Delta measurement
with some of these problems can remain in service for ten years or more without failing. The difﬁculty is deciding whether a defect detected by PD analysis is of this type, or whether it is of a type that will result in the cable failing much more quickly. PRPD can help to answer this question. With PRPD, PD intensity is essentially plotted against the phase angle of the applied test voltage. This produces patterns – see examples in Figures 1 and 2 – the characteristics of which are different for different types of defect. This is not, in fact, a new idea. It has been used with motors and generators for many years, but its application to cable diagnostics is novel.
facilities with automatic interpretation of the test results in line with IEEE 400.2, and they support PD analysis with VLF sinewave, DAC
By recognising and categorising the PRPD pattern, it is possible to assign it to a speciﬁc discharge family and thereby distinguish, for example, between corona, surface/interfacial and cavity discharges. This provides valuable information about whether a fault detected by PD analysis is likely to cause a failure in the near future, or whether it is likely to remain dormant almost indeﬁnitely. Like most test techniques, PRPD is not a panacea. In particular, it provides little or no useful information if there are two or more faults on a cable. The main criteria for evaluating defects are still PD inception voltage, PD level (in combination with location data), PD repetition rate and PD concentration. Nevertheless, PRPD is another very useful tool in the cable engineer’s testing toolbox. We’ve seen that PD analysis is an inexpensive and relatively easily implemented method of checking the quality of workmanship on newly installed cables and that this analysis can be carried out using a variety of different voltage waveforms, each with their own advantages and drawbacks. We have also seen that the new products in the Megger TDM range mean that one product puts testing with all of these waveforms at the ﬁngertips cable test engineers, allowing them to choose the most appropriate for every application. Finally, we’ve looked a new cable analysis technique – PRPD – that helps to categorise faults detected by PD analysis. Cable fault detection will always be challenging, but these new developments and options are, without doubt, starting to make life much easier and more convenient for its practitioners.
DAC test sets have a high test capacity for their size and VLF CR (50 Hz slope technology), with real-time data evaluation. Finally, they also offer monitored withstand testing. By offering a choice of four test waveforms in one device, TDM series test sets allow engineers to choose the best option for each and every application. DC is available for sheath testing and sheath-fault pin pointing, VLF sinewave for standards-compliant testing of short cables and for Tan Delta or PD diagnostics, VLF CR for standards-compliant testing of longer cables and PD diagnostics with 50 Hz slope technology, and DAC for guaranteed non-destructive PD diagnostics. These versatile cable test sets are available in vehicle-mounted or transportable versions, and feature modular construction that allows users to purchase only the components they initially need, with the option of easily adding extra functionality in the future. A particularly interesting feature of the new test sets is their support for phaseresolved PD (PRPD) pattern analysis. It is generally accepted that PD diagnostics will ﬁnd all but a very small minority of workmanship-related problems in cables. It is also widely known, however, that cables
20 | ADVERTISEMENT FEATURE
Smart power transformer maintenance How OMICRON’s Primary Test ManagerTM software can improve power transformer testing
MICRON’s Primary Test ManagerTM (PTM) software was optimized for initial screening, diagnostic testing and condition assessment of power transformers with the release of software version 4.00. All common chemical, electrical and dielectric tests on power transformers are now supported by one software.
SMART TESTING With proper testing and maintenance, the lifetime of a power transformer can be extended by identifying and ﬁxing defects before they can cause severe failures. A smart combination of an initial screening, e.g. by performing dissolved gas analysis (DGA) and power/ dissipation factor tests, and focused diagnostic testing is often utilized to keep the lifecycle management process more cost efﬁcient. A variety of other electrical test methods, such as transformer turns ratio, DC winding resistance, short-circuit impedance as
well as advanced methods such as dielectric response analysis or sweep frequency response analysis (SFRA), can be used to diagnose different problems within the power transformer.
CONDITION DIAGNOSIS IN THE PAST AND NOWADAYS In the past all test data had to be transferred manually from the individual test devices to one common ﬁle. Comparisons and reports also had to be prepared manually. Since the software release 4.00, PTM supports all common diagnostic tests performed with various OMICRON test systems as well as the corresponding condition assessment, such as the assessment of DGA test data. Thus, all data can be collected in one database, resulting in advantages such as overall assessment, easy data management, data comparison, trending, one comprehensive report and less training effort for employees. Combined with the time-saving advantages of new OMICRON test systems such as the TESTRANO 600 three-phase power transformer test system and the DIRANA for dielectric frequency response analysis, power transformer testing can be done in a fraction of the time needed in the past.
IDEAL SOFTWARE FOR MEDIUM AND HIGH-VOLTAGE ASSET TESTING In addition to diagnostic testing and condition assessment of power transformers and associated equipment such as bushings and onload tap changers (OLTC), PTM can also be used for circuit breakers, current and voltage transformers, and rotating machines. The software guides its user through the testing process with comprehensive testing procedures and detailed wiring diagrams. The performed tests can be automatically assessed in accordance with the applicable international IEEE and IEC standards. Powerful reporting functionalities such as customized, individual reports on test objects, test results and assessments complete the service.
COMPANY PROFILE OMICRON is an international company serving the electrical power industry with innovative testing and diagnostic solutions. The application of OMICRON products allows users to assess the condition of the primary and secondary equipment on their systems with complete conﬁdence. Services offered in the area of consulting, commissioning, testing, diagnosis and training make the product range complete. Customers in more than 170 countries rely on the company’s ability to supply leading edge technology of excellent quality. Service centers on all continents provide a broad base of knowledge and extraordinary customer support. All of this together with our strong network of sales partners is what has made our company a market leader in the electrical power industry. OMICRON electronics David Brazier email@example.com +44 1785 251 000 www.omicronenergy.com Electrical Review | May 2017
ADVERTISEMENT FEATURE | 21
22 | FACTORY AUTOMATION
Collaborative robots and worker safety? It can be done Humans are working in closer proximity to robots than ever before thanks to advances in safety technologies. George Schuster, TÜV functional safety expert (FSExp)and business development manager at Rockwell Automation explains
ollaborative robotic applications are fundamentally changing the way people and machines interact on the plant ﬂoor. This collaboration allows manufacturers and industrial operators to combine the strength, repeatability and tirelessness of machines with the ﬂexibility, adaptability and intelligence of humans. The result: an unmatched combination that improves production efﬁciency and ﬂexibility, while also reducing the physical burden on humans. Such capabilities are more important than ever as companies seek new ways to retain their skilled but aging workers. One of the key enablers of collaborative robotic applications is the safety technology that allows humans and robots to share the same workspace with less risk of human injury. Advancements in these technologies are reducing the need for safety cages, freeing ﬂoor space, saving money and increasing ﬂexibility in the way robots are used on the plant ﬂoor. The safety technology is increasingly embedded in the robot and in the cell controller. Sophisticated sensors, safety controllers and communication networks provide real-time safety data that allows robots to automatically respond to potential incidents, such as coming into contact with an operator. Today’s standards – provided by the Robotic Industries Association and various safety standards bodies – offer guidance on how robots and humans can work together to revolutionise productivity and safety in industrial operations.
IMPLEMENTING COLLABORATIVE ROBOTICS A robot is not collaborative by itself. A collaborative robot is only one part of a collaborative robotic application, and it does not achieve safety compliance on its Electrical Review | May 2017
own. The way the system is designed is critical for optimising worker safety and enabling compliance. According to standards ANSI/RIA R15.062012 and ISO 10218, the term ‘collaborative robotics’ describes an automatically operated robot system sharing the same workspace with a human, and there are four types of collaborative operations. They are deﬁned as: Safety-rated monitored stop: This method is the most common and has been used in industrial operations for many years. Sensors in the safety control system
Studies are being conducted
detect human presence and immediately stop the robot if a human gets too close. This is commonly used when humans and robots are working in close proximity or with overlapping work envelopes. For example, a worker can load parts directly onto a robot end-effector while it is in a safe-stop condition. This can help improve productivity because the machine can keep running independent from the robot. Hand-guiding operation: This method, which is less common, allows operators to manually control or reposition the robot for its next task. In this case, the operator is in direct contact with the robot arm and can utilise hand controls to reposition it. This generally doesn’t work well for tasks that require fast speeds. Speed and separation monitoring: This method allows operators and robots to
work in the same space while maintaining sufﬁcient distance from each other. If a human comes too close to a robot, sensors will trigger the robot to slow down or stop. New safety sensor technology is making this application more popular in industrial operations. Power and force limiting: In this method, if a robot accidentally comes into contact with a human, the robot reduces its force or torque so the human isn’t hurt.This is an emerging method and arguably the least commonly implemented. The robot needs to actually come into contact with a human before it knows to stop. Implementing this method requires understanding the relationship between different levels of force and pain thresholds on various parts of the human body. Studies are being conducted to explore this method and make it possible. For example, standard ISO/TS 15066 outlines ﬁndings from one study on pain tolerance, which includes a list of maximum force and pressure levels for each part of the human body to help determine power and force limits. The standard provides some guidance on how to conduct a risk assessment for each part of the human body that could come into contact with a robot. Most of these methods are intended to prevent humans from coming into physical contact with robots and machinery, but it’s still critical to follow the functional safety lifecycle when designing collaborative robotics applications. The lifecycle, as deﬁned by ISO 12100 and ANSI B11:0, includes conducting a risk assessment as the ﬁrst step, followed by deﬁning functional speciﬁcations, using proper guarding and completing veriﬁcation and validation testing. Following the safety lifecycle is increasingly important as humans and machines work more closely together.
FACTORY AUTOMATION | 23
ASSESSING RISK A proper risk assessment evaluates the way humans, machinery and robots are designed to interact with each other during all modes of operation. This helps identify all of the ways a human could potentially come into contact with a robot, evaluate the associated level of risk, and mitigate that risk using appropriate measures. ISO/TS 15066 provides guidance for the design of collaborative workspaces and how to conduct a risk assessment for collaborative robot applications. It supplements ISO 10218-1 and ISO 102182. In addition, RIA TR R15.306 provides a recommended methodology for conducting task-based risk assessments to meet the standardâ&#x20AC;&#x2122;s requirements.
THE FUTURE The growth of collaborative robotics is a new era for industrial operations. Their
usefulness spans different industries and applications â&#x20AC;&#x201C; from taking over repetitive and heavy-lifting tasks to handling complex assemblies or even meeting stringent quality requirements. Getting there, however, will involve a number a changes for engineers, OEMs and
end users, including adopting new standards, tools and methods of analysing risk Organisations that embrace these changes will be better positioned to realise the many efďŹ ciency and productivity gains afforded by collaborative robots while optimising worker safety and compliance.
24 | ABB
Synchronized microgrids can bring security of supply to smart cities Peter Jones, ABB Technology Strategy Manager, explains that microgrids are not just for remote off-grid communities, increasingly they will play a key role in smart cities renewable energy sources, or by injecting power to make up for short term lulls to maintain a stable voltage and frequency in both the microgrid and main grid. There are other reasons interest in microgrids is growing. They can provide the
verall, there are three principal drivers behind the increasing interest in microgrids: • The availability and affordability of smart technology that is making microgrids both possible and commercially viable. • An Increasing awareness that microgrids can take many forms and can adapt to various system conﬁgurations. • A fear of supply failure due either to a lack of reliability in the main grid or the potential for infrastructure damage from external events such as storms. There are basically three types of microgrids. The ﬁrst – an isolated microgrid – could literally be an island, off the coast of Scotland for example, or a remote military facility. In this case there is no main grid to connect to, and often the purpose of this type of microgrid is to use as much renewable energy as possible. But renewables are intermittent or variable resources, so energy storage may be required, and all this needs to be controlled and optimized. The second type is a grid-connected microgrid, such as found at university campuses, business campuses and data
Electrical Review | May 2017
centres. Normally these facilities draw their power from the grid, but when the main grid goes down, they can separate and operate as an island, using their own multiple on-site sources such as diesel generators, renewable energy resources and energy storage. The third type is a utility-owned embedded microgrid that uses local generation to power critical customers for example industrial facilities or hospitals in the event of a grid disruption. Effectively, it’s an investment in reliability and resiliency. The reliability beneﬁts of microgrids have been known for years. That’s why hospitals, military bases and other vital facilities were the ﬁrst to adopt them. Very simply, when a natural or man-made event disrupts the main grid, the microgrid switches to island mode and uses existing distributed generation – local diesel, microturbine, wind, solar, hydro, or battery power – to keep the lights on and to power essential services. When power is restored to the main grid, and after a ‘synch check’ the microgrid reconnects to the grid and local generation can shut down. But microgrids can also be used to stabilize the grid itself by rapidly absorbing power surges from the
means to control and coordinate disparate distributed energy resources to increase their reliability and efﬁciency. They also represent an entirely new way of powering remote or rural communities. Rather than one centralized generating plant - powered typically by diesel – they can be powered by a large number of low-emissions generators, linked with appropriate load control. Finally, they can provide enhanced power quality, which is absolutely critical for customers engaged in advanced manufacturing.
THE RETURN ON INVESTMENT Naturally, cost is a consideration. While microgrids involve investment in power generation, controls, sensing, and communication technologies, the capital outlay is often much less – and payback signiﬁcantly faster – than other approaches to reducing risk and optimizing reliability. For example, microgrids can offer a very cost-effective approach compared to the major capital outlay involved in installing new power connections. The net effect of the new developments in microgrid technologies is that they are no longer seen as purely for off-grid applications, they are becoming increasingly attractive as an integral element of smart city solutions. And there are now a growing number of case studies that provide persuasive evidence of the capability of grid-connected microgrids to ensure total continuity of supply. Below is just one example:
SMART ISLANDING FOR MANUFACTURING FACILITY An integrated solar–diesel microgrid has been installed at ABB’s Longmeadow
ABB | 25
facility in Johannesburg, South Africa. This integrates multiple energy sources and battery-based stabilization technology within a smart control system that facilitates seamless disconnection and reconnection to the local utility grid. During the regular power outages that affect the country the campus is now able to disconnect from the grid to operate as its own ‘power island’ – ensuring that business continues as normal. While continuity of supply is the critical factor, the ABB system also optimizes the site’s use of green solar power to reduce its reliance on increasingly expensive and polluting diesel fuel. South Africa has the highest electricity consumption in the sub-Saharan region and demand continues to outpace supply. This means there is a rolling schedule of planned blackouts (load shedding) to ensure demand does not outstrip supply and maintain grid stability. However, the country’s businesses and production facilities all need an uninterrupted power supply to maintain continuous operation. Many therefore rely on diesel generators to provide backup power supply. This situation is not uncommon in many other parts of Africa and other parts of the world, such as South America, where increasing demand for electricity is outpacing generating capacity. In recent years, fossil fuel price volatility, environmental concerns and an increased focus on renewable energy sources have been driving a desire for smarter and more sustainable solutions to this challenge. Hence the growing popularity in gridconnected microgrids to help address rising power demands, take advantage of the falling cost of renewable sources, and improve supply resilience and autonomy, especially for critical applications.
ABB FACILITY SHOWS THE WAY ABB’s 96,000-square-meter Johannesburg facility houses the company’s national headquarters, as well as manufacturing facilities, with around 1,000 employees. It is supplied with power by an 11 kV grid connection to the local utility. The average daily energy consumption of the facility equates to around 2,000 typical South African households. Its energy demand has been relatively constant over the past few years, but the cost of energy is rising steadily. Since 2009, two 600 kVA diesel generators
have provided backup for around 100 utility power outages per year. To address this challenge, ABB has implemented an innovative microgrid solution by adding a 750 kW rooftop solar PV (photovoltaic) array, 1 MVA/ 380 kWh battery energy storage and an overall control solution to the existing grid and diesel generator backup system. This worldleading solution offers fully grid-connected and off-grid functionality designed to maximize the use of renewable energy and ensure uninterrupted power supply. The seamless transition to islanded operation keeps the facility running smoothly during both scheduled rolling blackouts or unplanned power outages. The battery energy storage plays a vital role in ensuring the smooth transition from grid to backup power during outages. It also enables peak shaving during peak consumption times. Above all, the PV–battery combination reduces the consumption of – and therefore, spending on – both grid-provided electricity and diesel fuel.
motorized circuit breaker opening to avoid feeding back into the grid. The battery storage provides power to the load and maintains voltage and frequency to ensure that PV plant stays on line. For extended outages, one of the generators automatically starts up, ramps up speed and synchronizes to take over the load with the PV plant. If a single generator is not enough to meet demand, the second generator is started. The main purpose of the PowerStore (a compact and versatile grid stabilizing generator) is to stabilize the power system against ﬂuctuations in frequency and voltage. It does this by rapidly absorbing/ injecting power. State of the art inverters with virtual generator mode capabilities have been deployed that make it possible for the diesel generators to be switched off for most of the time. The solution can also ensure a bumpless transition from grid connected to island mode when there are outages on the grid. A cloud-based remote service system enables remote operation and maintenance of the microgrid.
INTELLIGENT, OPTIMIZED CONTROL
The microgrid is managed by ABB’s Microgrid Plus energy management system that provides dynamic control for multiple energy sources, enabling autonomous and automatic self-healing operation as well as demand response management. This enables the overall microgrid solution to manage the supply of power and balance the fossil-fuel and renewable energy sources in accordance with loads, in a coordinated manner, preserving access to utility-grade power at all times. During normal operation, power is generated by PV plant, supplemented by the grid. In the event of an outage, the microgrid enters ‘island’ mode, with a
With the microgrid, diesel fuel consumption at the facility has been reduced by around 27 percent. In addition, the generators are now running for only 106 hours annually, compared with 433 hours without the microgrid – a 75 per cent reduction in running time. As well as substantially reducing the operational costs of the industrial complex, this environmentally-friendly solution has helped cut its CO2 emissions by an estimated 1,000 tons per year. The net effect of the microgrid for ABB’s Johannesburg facility is that it is always ‘business as normal’ for the site, no matter what is happening on the local grid. www.electricalreview.co.uk
SWITCHGEAR/SUBSTATION TECHNOLOGY | 27
Witness the FITNESS for digital substations Danny Lyonette, business development and innovation manager for ABBâ&#x20AC;&#x2122;s Grid Automation business unit within the Power Grids division in the UK, explains the advantages of digital substations and outlines the FITNESS project that will deliver the 8.ÂˇV Ă&#x20AC; UVW PXOWLYHQGRU GLJLWDO VXEVWDWLRQ PRQLWRULQJ FRQWURO DQG SURWHFWLRQ V\VWHPV
ntil recently, the digital substation has been regarded as an idealised future concept based on all-knowing substations networked into an intelligent grid. However, the concept is now turning into reality with the ďŹ rst practical projects that now enable a meaningful discussion about what makes a substation â&#x20AC;&#x2DC;digitalâ&#x20AC;&#x2122;, and why this might be desirable.
DIGITAL MESSAGING The ďŹ rst attribute is ďŹ bre-based digital messaging that offers excellent reliability and capacity. This has been in use in power infrastructure for decades. In fact, many existing electricity grids already employ ďŹ bre optic networks for their substation automation systems. But only now are
the advantages of standardised digital messaging starting to extend into the deeper substation environment. A key step has been the adoption of the IEC 61850 standard â&#x20AC;&#x2DC;for communications networks and systems for power utility automationâ&#x20AC;&#x2122;. It provides a comprehensive standard broken down into components that, for example, specify how the functionality of substation devices should be described â&#x20AC;&#x201C; how they should communicate with each other, what they should communicate and how fast that communication should be. At the station level, things are generally digital, even in relatively old installations, since SCADA (supervisory control and data acquisition) systems usually demand digital information. Between the station level and the bays, ďŹ bre optics can carry digital data.
But to become a true digital substation it is necessary to go deeper.
DEEP DIGITAL In conventional substations information from the primary equipment is connected back to intelligent electronic devices (IEDs) using multiple copper wires carrying analogue signals. The IEDs receiving the analogue data perform ďŹ rst-level analysis and provide the gateway into the digital world. A true digital substation converts the analogue data at the primary interface point and takes it into the digital domain at the source, enabling multiple copper cables to be replaced by a single dual redundant ďŹ bre optic cable. Through permanent system supervision, digital equipment reduces the need for www.electricalreview.co.uk
SWITCHGEAR/SUBSTATION TECHNOLOGY | 29
manual intervention. The digital equipment that has to be located out in the switchyard must be easy to install, and every bit as robust and reliable as the analog equipment it is replacing or interfacing to.
NONCONVENTIONAL INSTRUMENT TRANSFORMERS (NCITS) Robustness and reliability requirements apply to the adoption of nonconventional instrument transformers (NCITs) that can make things entirely digital. Over the past decade, ABB has supplied more than 300 NCITs (combined current and voltage sensors ﬁtted into gas-insulated switchgear) for use in Queensland, Australia, and the utility has yet to see a single failure in the primary sensor. Extensive use of NCITs makes a substation simpler, cheaper, smaller and more efﬁcient. An excellent example of an NCIT is ABB’s ﬁbre-optic current sensor (FOCS) that directly monitors current running through a highvoltage line without having to involve a current transformer (CT) to step down the current to a measurable value. Eliminating the CT also eliminates the risk of open CT circuits, in which life-threatening voltages can occur, and so increases safety. Not everything can be digital – for example, analog data will continue to arrive from conventional current and voltage transformers. In any case, there is no need for wholesale replacement when a standalone merging unit can perform the transition to digital right beside the existing instrument transformer. Fibre optics can then replace the copper cables connecting the primary equipment to the protection and control IEDs.
DIGITAL PROCESS BUS DISPENSES WITH COPPER Every piece of copper in a substation represents a potential risk. For example, where current is incorrectly disconnected, such as with an open secondary current transformer, arcing may occur as dangerously high voltages build and a copper line can suddenly carry high voltage, putting operators and equipment at risk. Reducing the amount of copper increases safety. A digital substation dispenses with copper by using the digital process bus, based either on ﬁbre optics or a wireless network. In some cases, just the potential to reduce the quantity of copper wires in a substation by 80 percent might on its own
justify the switch to digital. Not only is there a substantial cost saving, more importantly there is a signiﬁcant safety enhancement. The process bus also adds ﬂexibility since digital devices can speak directly to each other. For this, IEC 61850 deﬁnes the GOOSE (generic object-orientated substation events) protocol for fast transmission of binary data. Part 9-2 of the standard describes the transmission of sampled values over Ethernet. These principles ensure the timely delivery of high-priority data via otherwise unpredictable Ethernet links.
READY FOR FITNESS The UK’s ﬁrst multivendor digital substation monitoring, control and protection systems are being implemented at Scottish Power Energy Networks’ 275 kilovolt (kV) Wishaw substation as part of the FITNESS (Future Intelligent Transmission Network Substation) project. The FITNESS project, funded as part of the RIIO NIC (Network Innovation Competition), is running for four years from April 2016 with the aim to demonstrate a fully integrated multivendor digital substation solution both for retroﬁt and new build projects. The main driver is that substation control and protection requirements need to change signiﬁcantly as low carbon generation and HVDC (high voltage direct current) interconnections increase, and these changes present new challenges for traditional network control and protection functions. In addition, conventional substations allow little ﬂexibility to adopt the necessary new monitoring, protection and control functions – especially where these are to be linked with external measurements and information systems such as WAMS (wide area monitoring systems). The project will equip two bays of the existing Wishaw substation with new fully integrated digital protection and control equipment. The site has been selected as it is in an area of special interest with a large wind power infeed that presents challenges in terms of variability and inertia. The project will also trial new sensor technologies for voltage and current measurements. The substation will be designed with digital communications using ﬁbre optic cables – instead of analogue signals using copper cables – from switchyard to control building. Projections show a 10 percent saving in substation costs while their footprint can be reduced by around 15 percent when digital technology is adopted as the UK norm.
Another speciﬁc objective of this project is to ensure that the equipment is interoperable within a multivendor solution. The industry has already seen a widespread adoption of IEC 61850, the standard that deﬁnes substation communication protocols and the need for interoperability of systems. But there has so far been a slow uptake in truly digital substations. One of the main reasons for this is uncertainty over the technical maturity, performance, reliability and robustness of the equipment, especially because there is limited experience within the industry of demonstrating how a full IEC 61850 digital substation will work. The key beneﬁt from FITNESS is in providing the industry with conﬁdence in the new systems. Nevertheless, not every substation needs to be catapulted into a wholesale digital world – it depends on the substation size and type, and whether it is a new station or a retroﬁt of the secondary system. The FITNESS project will help develop different approaches and ﬂexible solutions to enable utilities to adopt digital substation technology that is the right ﬁt for their infrastructure. www.electricalreview.co.uk
30 | Q & A FEATURE
Electrical safety leader adds power quality monitoring to its portfolio • Range: We actively develop new solutions used across a range of market sectors. • People: Our team at Bender UK are friendly, dedicated and knowledgeable. • Competency: We concentrate on our core competency “Electrical Safety”. • Markets: We actively develop new solutions for new markets.
4. WHICH SECTORS DO THE COMPANY FOCUS ON IN THE MAIN? Our products are used in diverse markets. In the UK and Ireland we are strong in healthcare, defence, shipping, process, rail, and oil and gas markets.
5. WHICH HAS SEEN THE BIGGEST GROWTH SECTOR OVER RECENT YEARS?
Power quality meters installed in the new Bender UK facility
1. COMPANY INTRODUCTION: Bender UK is part of the global Bender Group - an independent family business with ofﬁces worldwide. Founded in the 1940’s by Dipl.-Ing Walter Bender who invented and patented the world’s ﬁrst insulation monitoring device, Bender has grown to become a reputable, world leader in the design and manufacture of electrical safety solutions. Bender UK is responsible for the sale, technical support and service of Bender products in the UK and Ireland - delivering solutions which identify electrical faults before they are critical, so that downtime is avoided and vital services are protected. Market leading products include: insulation monitoring devices, residual current monitoring systems, earth fault location systems and power quality solutions.
2. WHAT IS YOUR BACKGROUND BEFORE JOINING BENDER? Mumtaz Farooqi: After completing a Masters in Electrical and Communications Engineering I worked at Manchester University as a research assistant. I have Electrical Review | May 2017
also worked for Siemens and Schneider Electric in techno-commercial roles developing and launching new concepts and products.
3. WHAT DO YOU THINK IS THE MAIN REASON YOUR CUSTOMERS ARE DRAWN TO AND RETURN TO BENDER? Bender is a quality focused company from products to customer service. Our solutions result from preventing or solving customer problems. Customers choose Bender because: • Technology Leader: We are the technology leader and set standards of excellence in technical innovation and quality. • Value: Our products are competitively priced, delivering long term value for money. • Approvals: Our products hold the necessary approvals such as TUV, Lloyds, Def Stan, Network Rail, SIL etc… • Quality: German manufactured high quality solutions with ﬁve year warranties. • Support: We provide product training, technical support, service and a 24/7 365 call out service to our customers in the UK and Ireland.
Healthcare has witnessed the most growth, combined with the service of Bender and third party medical devices. We have an outstanding team who provide 24/7 service and technical support. Our clients say the quality of our service sets us apart from other companies.
6. ARE THERE ANY NEW SECTORS THE COMPANY IS LOOKING AT COVERING? From a strategic perspective, we operate in distinct markets. However, we are always looking at new and innovative applications which cannot afford their systems to fail. Process plants such as food and beverage, paper mills and pharmaceuticals beneﬁt from Bender residual current monitoring technology which provides signiﬁcant advantages and cost savings when installed.
7. DOES THE COMPANY HAVE AN ENVIRONMENTAL POLICY? Bender UK has IS0 14001.
8. BENDER HAS LAUNCHED A RANGE OF NEW POWER QUALITY METERS (PQM). ARE THEY AIMED AT PARTICULAR MARKET SECTOR/APPLICATIONS? Bender PQM complements our existing product portfolio. They are also installed into our medical isolated power systems to monitor energy usage. They can be used
Q & A FEATURE | 31
anywhere from LV to HV applications including infrastructure and utilities where energy management is required up to the 63rd harmonic.
10. HOW LONG WERE THE PRODUCTS IN DEVELOPMENT FOR, AND IS YOUR RESEARCH AND DEVELOPMENT UK BASED
9. TECHNICALLY HOW DOES EACH PRODUCT DIFFER FROM ANYTHING PREVIOUSLY OFFERED BY YOURSELVES OR COMPETITIVE COMPANIES?
All products are designed by our 120 strong Research and Development team who are continuously working on new product developments and customised variants.
The market does have similar products available. Some were designed for grounded systems, therefore when used in non-grounded systems would deteriorate system measurements. Furthermore, some competitor’s products are more basic, or when of a higher speciﬁcation tend to be too expensive and difﬁcult for system integrators to use. Bender is different as we have open protocol software with no further costs associated with using our products.
11. WHERE ARE THE PRODUCTS MANUFACTURED? Our products are manufactured in state of the art facilities in Grünberg, Germany.
PEM735 is the premium Bender power quality monitoring device
We have a strong, reputable brand with competitively priced, high quality products.
12. DO YOU HAVE ANY OTHER NEW PRODUCTS? Yes - our most recent is Powerscout® cloud based software to analyse, predict and report on the information obtained from Bender and third party devices.
NEW BENDER UK HEADQUARTERS SHOWPIECE OF TECHNOLOGY Electrical safety and monitoring specialist Bender UK has moved into a new purpose-built headquarters in Ulverston, designed to accommodate further growth and be a showpiece for the company’s advanced technology The 2000m² building accommodates ofﬁces, large conference facilities, warehousing, training and customer demonstration areas. Bender surgical lighting, touch screen theatre control panels and other critical care medical solutions will be permanently on display for client demonstrations and training. The facility is also equipped with Bender continuous monitoring technology to enable predictive maintenance of the building’s electrical infrastructure. Managing director Gareth Brunton explained: “Our purpose-built facility represents a major investment by Bender Group in its UK operation. It provides superb facilities for the training and 24/7 technical support provided to customers across the UK & Ireland. Bender UK has doubled in size since 2010 driven by its ability to deliver bespoke engineered solutions and advanced service and support capabilities for speciﬁc markets including the medical sector, renewable energy, rail infrastructure, data centres, power distribution, offshore subsea development, the oil and gas industry, marine and manufacturing. Residual Current Monitoring (RCM) and Power Quality Metering (PQM) incorporated into the new Bender UK facility will be used to demonstrate for visitors the practical advantages in terms of efﬁciency and cost-savings. The integrated solution also provides early warning of faults or failure for all critical aspects of the building’s electrical infrastructure. Power supply performance and resilience is critical to health trusts, data centres, high value manufacturing operations and other locations which cannot afford their supply to falter or fail. Bender’s continuous
intelligent monitoring systems provide a comprehensive overview of power networks. It enables energy costs to be identiﬁed and reduced, while protecting critical power systems and achieving maximum availability of electrical supply. Continuous monitoring and reporting also provides the option of periodic inspection and testing without switch off. The new building’s electrical infrastructure includes a 12-channel RCMS460 which monitors the main distribution board, while RCMS150 devices monitor local distribution within the building across ofﬁces and meeting rooms, and critical areas such as the plant room and air conditioning system. Bender devices monitor the frequency, current, power performance, energy consumption and harmonics to present a detailed picture of the building’s power infrastructure. The new facility is connected to PowerscoutTM the latest Bender software development which delivers analysis, reporting and live data on the status of the building. This smart cloud-based technology produces reports from the residual current monitoring and power quality metering technology onsite, enhancing pro-active analysis, fault ﬁnding and maintenance. Data can be accessed on site or remotely via internet links which particularly beneﬁts operations with multiple sites. Brunton added: “The installation of Bender’s class-leading power quality monitoring systems together with new Powerscout web-based software ensures that the new building is a showcase for advanced predictive maintenance and remote monitoring. That is technology set to make a huge impact on the healthcare sector and other ‘no-fail’ markets where resilience of power supply is a critical factor.” Bender UK purchased the development plot opposite its previous base at the entrance to the Low Mill Business Park in Ulverston and began construction on the project earlier this year. www.electricalreview.co.uk
32 | ARC FLASH
AC and DC – electrical hazards The electric shock hazard from both ac and dc power systems has been well documented and understood for decades thanks to the research of people like Charles Dalziel. Jim Phillips, PE, explains
A subsequent paper titled: “DC-Arc Models and IncidentEnergy Calculations” by R. F. Ammerman, T. Gammon, P.K. Sen and J. P. Nelson (referred hereafter as “DC Arc Models”) provides a comparison study of the existing body of research into dc arcs and arc ﬂash modeling that has been conducted over the years. It also provides a series of calculation methods for determining the incident energy from a dc arc ﬂash in open air as well as in a box. The DC Arc Models paper is the basis for dc arc ﬂash calculations that are currently used by many in the industry, including several arc ﬂash software packages. Calculating the incident energy for a dc arc ﬂash begins with a simple application of Ohm’s law which states: I = V/R Where: I = Current in amperes V = Voltage in volts R = Resistance in ohms
ven our understanding of the arc ﬂash hazard has greatly improved thanks to years of research by many individuals and also the introduction of IEEE 1584 - IEEE Guide for Arc Flash Hazard Calculations in 2002. However, when performing arc ﬂash calculations, IEEE 1584 only addresses alternating current (ac) arc ﬂash hazards. At the present time, there are no standards for calculating the arc ﬂash hazard for direct current (dc) power systems. Even though dc power systems and equipment are not as prevalent as ac, dc systems are found everywhere and include rectiﬁers, traction power systems, adjustable frequency drives, photovoltaic systems, battery banks and much more. In fact, dc arc ﬂash is the proverbial “elephant in the room”.
DC ARC FLASH CALCULATIONS – A WORK IN PROGRESS Two landmark technical papers were published that began to change the understanding of dc arc ﬂash. The ﬁrst paper helped elevate the discussion of dc arc ﬂash calculations and is titled: “Arc Flash Calculations for Exposures to DC Systems” by D. R. Doan. It was published in IEEE Transactions on Industry Applications, Vol. 46, No. 6. This paper provides a theoretical approach to dc incident energy calculations based on the concept that the maximum possible power in a dc arc ﬂash occurs when the arcing voltage is 50% of the system voltage. The equations from this paper were ultimately included in the informative annex of the 2012 Edition of NFPA 70E and remain in Annex D of the 2015 edition Electrical Review | May 2017
FIGURE 1. Ohm’s Law and dc Arc Flash Calculations
By including the dc arc resistance as part of the dc circuit model illustrated in Figure 1, the arcing current can easily be determined. This circuit diagram is of a battery string and includes the dc voltage, dc battery resistance, conductor resistance and dc arc resistance. As part of the overall process, the dc arc resistance must also be calculated since it is usually not known. Once all of the resistance values have been determined, the dc arcing current, Idc arc can be calculated by: Idc arc = Vdc / (Rbattery + Rconductor + Rarc) The DC Arc Models paper also refers to another important document titled “Electric Arcs in Open Air” published in the Journal of Physics D: Applied Physics in 1991 by A. D. Stokes and W. T. Oppenlander. The research included in this document led to the development of the following equation for arc resistance: Rarc = [20+ (0.534 x G)] / (Idc arc 0.88) Where: Rarc = resistance of the arc in ohms G = conductor gap distance in millimeters Idc arc = dc arcing current
ARC FLASH | 33
In order to calculate the arc resistance using this equation, the conductor gap distance G and the dc arcing current must be known. The gap distance is speciﬁed by the user however, in order to determine the dc arcing current, the arc resistance must already be known. This creates an interesting dilemma since the arcing current is needed to calculate the arc resistance and the arc resistance is needed to calculate the arcing current. To solve this problem, an iterative solution can be used. This requires making an initial assumption of the dc arcing current. A reasonable assumption is that the dc arcing short circuit current is 50% of the dc bolted short circuit current. Once this initial assumption is made, the dc arc resistance can be calculated which is then used to re-calculate the dc arcing current. The “new” dc arcing current can then be used to re-calculate the dc arc resistance. This process continues until the dc resistance and dc arcing current values no longer change signiﬁcantly and converge to a ﬁnal answer.
Calculation Studies” by J. Phillips, published by Brainﬁller, Inc. 2010. ISBN Number 978-0-615-48691-8. The dc arc resistance worksheet shown as Figure 3, is used for calculating the dc arc resistance of this example. It provides a step by step method for calculating the dc arc resistance based on the Stokes/Oppenlander equation. To use the worksheet, the following data is required: • Conductor gap distance in millimeters (mm) • DC arcing current
FIGURE 3. DC Arc Resistance Worksheet
DC ARC RESISTANCE AND DC ARCING CURRENT CALCULATIONS - ITERATIVE SOLUTION Figure 2 illustrates the circuit that is used as an example for calculating the dc arc resistance and the dc arcing current. The calculation process begins by determining the dc bolted short circuit current ﬁrst. This requires taking the dc voltage (Vdc) and dividing by the known impedances of the conductor and battery string.
FIGURE 2. DC Arc Flash Example
Begin by solving for the bolted dc short circuit current using the values Figure 2. For the bolted case, Rarc and the conductor gap distance are ignored and only the resistance of the battery string and conductor are used. Idc bolted = Vdc / (Rbattery + Rconductor) Idc bolted = 256V / (0.01150Ω + 0.00194Ω) = 19,048 Amps As a ﬁrst approximation of the dc arcing current, Idc arc: Idc arc = 0.5 x Idc bolted Therefore: Idc arc = 0.5 x 19,048 Amps Idc arc = 9524 Amps
DC ARC RESISTANCE WORKSHEET There are so many calculation steps to keep track of that I developed a series of worksheets in 2010 for my arc ﬂash training program that can be used to simplify the calculations process. These worksheets as well as the examples that follow are from the book “Complete Guide to Arc Flash Hazard
Step One: Enter the conductor gap distance G in millimeters (mm) and multiply by 0.534. The gap distance must be deﬁned by the user. IEEE 1584 provides a table of “typical” gap distances. Step Two: Add the constant 20 to the result found in Step One Step Three: Enter the arcing short circuit current, Idc arc and raise it to the power of 0.88. Since the arcing short circuit current is not usually known, a typical ﬁrst approximation is to assume that Idc arc = 50% of Idc bolted. Step Four: To obtain the dc arc resistance in ohms, divide Step Two by Step Three. The following example illustrates how to calculate the value of the dc arc resistance based on the initial assumption of the dc arcing short circuit current. After the dc arc resistance has been calculated, iterative solutions can be used. For this example, an arc gap of 25 mm was used which is one of the “typical” values given in IEEE 1584. Using the ﬁrst approximation of 9524 A which was calculated previously for the arcing short circuit current, the arc resistance Rarc is calculated as 0.01051 Ω as shown in Figure 3. The next step in this process requires a series of iterations. The calculated value of Rarc can now be added to the original circuit and the dc short circuit current can be re-calculated as follows: Idc arc = Vdc / (Rbattery + Rconductor + Rarc) Idcarc =256V / (0.01150Ω + 0.00194Ω + Rarc) Idc arc = 256 V / (0.01150 Ω + 0.00194 Ω + 0.01051 Ω) Idc arc = 10,688.9 Amps Once the new value of Idc arc has been calculated, it can be substituted back into the dc arc resistance worksheet and a new value of Rarc can be calculated. The iteration process continues until the values of Idc arc and Rarc do not change signiﬁcantly from the previous values and converge to the ﬁnal answers of 11,433.7 A for Idc arc and 0.00895 for Rarc as illustrated in Table 1 and Figure 4.
ARC FLASH | 35
A worksheet that is based on this equation and used to solve the arc ﬂash in open air example problem is shown as Figure 5. It breaks the calculation process down into individual steps. A ﬁnal step is added which converts the units from J/mm2 to the more commonly used units of calories/centimeter2 (cal/cm2).
TABLE 1. Iterative Solution for Example Problem
FIGURE 4. Results from Example Problem
POWER AND ENERGY IN THE ARC Once the dc arcing current and dc arc resistance have been determined, the power in the arc can be calculated by: Parc = Idc arc2 x Rarc Parc = power in the arc in watts Idc arc = dc arcing circuit current in amperes Rarc = dc arc resistance in ohms The energy in the arc is a function of power and time. Therefore, the energy in the arc can be calculated by: Earc = Parc x tarc Where: Earc = arc energy in watt·seconds or Joules tarc = arc duration in seconds
To use this worksheet, the following data is required: • DC arcing current in amperes, Idc arc • Arc resistance on ohms, Rarc • Arc duration in seconds, tarc • Distance from the arc in mm, d Step One: Enter Idc arc, Rarc and tarc obtained from the previous iterative calculations. Square the Idc arc value and multiply by Rarc and tarc to determine the energy in the arc, Earc in terms of wattsseconds or Joules. Step Two: Enter the distance from the arc (working distance) in mm. Multiply d by 4 x π or 12.56637 Step Three: Calculate Ei air by dividing Step 1 by Step 2. The result will be in J/mm2 Step Four: Convert the answer obtained in Step 3 from J/mm2 to cal/cm2 by multiplying by 23.9 Using the dc arcing short circuit current and arc resistance that was previously calculated, the incident energy can be calculated. This requires knowing the working distance from the prospective arcing location to the worker as well as knowing the duration of the arc ﬂash. For this calculation, a maximum arc duration of 0.3 seconds was used. This value would normally be deﬁned by the characteristic of an upstream protective device. A working distance of 18 inches (457 mm) was used which is a “typical” value obtained from IEEE 1584.
The duration of the arc ﬂash will either be dependent on the clearing time of an upstream protective device operating or the reaction time of a person jumping away from the hazard. IEEE 1584 presently suggests that a maximum time of 2 seconds may be used based on the reaction time and assuming there are reasonable conditions for a person to escape.
FIGURE 5. DC Incident Energy Worksheet - Arc Flash in Open Air
DC INCIDENT ENERGY CALCULATIONS - OPEN AIR
Similar to the IEEE 1584 calculation methods, consideration must be given to whether the dc arc ﬂash occurs in open air or in an enclosure/box. If the dc arc ﬂash occurs in open air, the energy will radiate spherically in all directions and the person would be exposed to a smaller portion of the energy. If the event occurs in an enclosure, the incident energy exposure will be greater since it is focused out of the box opening. According to the DC Arc Models paper, the incident energy for an arc ﬂash in open air at a speciﬁc distance can be calculated based on the following equation: Ei air = Earc / (4π x d2)
Earc = arc energy in watt-seconds or Joules (J) Ei air = incident energy from an open air arc at distance d in (J/mm2)
DC ARC FLASH IN AN ENCLOSURE / BOX If the dc arc ﬂash occurs in an equipment enclosure, the energy will be directed out of the open end of the box. For this calculation, the DC Arc Models paper refers to another technical paper titled “Simple Improved Equations for Arc Flash Hazard Analysis,” IEEE Electrical Safety Forum, August 30, 2004 by R. Wilkins. According to this paper, the equation for determining the incident energy from a dc arc ﬂash being focused out of an enclosure is: Ei box = k x Earc / (a2 + d2) www.electricalreview.co.uk
36 | ARC FLASH
Where: Ei box = incident energy from an arc ﬂash in a box at
in an enclosure as illustrated in Figure 6. The result for this calculation is 4.9 cal/cm2.
distance d in J/mm2 Earc = arc energy in watt·seconds or Joules d = distance from the arc source in mm a and k are obtained from optimal values deﬁned in the Wilkins paper and listed in Table 2.
FIGURE 6. Incident Energy Worksheet – Arc Flash in an Enclosure / Box
DC ARC FLASH CALCULATIONS AND STANDARDS TABLE 2 - Optimum Values of “a” and “k” From Wilkins Paper
A worksheet was developed for calculating the dc incident energy for an arc ﬂash in an enclosure/box. This worksheet is based on the box equation and reduces the calculation into a series of simple steps. To use this worksheet, the following data is required: • DC arcing current in amperes, Idc arc • Arc resistance in ohms, Rarc • Arc duration in seconds, tarc • aandkfromTable2 • Distance from the arc in mm, d Step One: Enter Idc arc, Rarc and tarc obtained from the previous iterative calculations. Square the Idc arc value and multiply by Rarc and tarc to determine the energy in the arc in terms of wattseconds or Joules. Step Two: The value of a must be obtained from Table 2. The value of the distance from the arc (working distance), d in mm must also be deﬁned. Enter each value in the appropriate space in Step Two. Square each value and add the two terms together. Step Three: Look up the value of k from Table 2 Multiply k and Earc from Step One Step Four: Divide Step Three by Step Two. The result will be the incident energy in terms of J/mm2 at working distance d. Step Five: To convert the units from J/mm2 to the more commonly used units of cal/cm2, multiply the answer obtained in Step Four by 23.9 Using values that were previously calculated for Idc arc and Rarc, the incident energy will now be calculated based on the arc ﬂash occurring in a box/enclosure. The enclosure is assumed to be a panelboard and the same working distance and arc duration from the earlier example are used. To begin this problem, the values of a and k must be determined. Obtaining these values from Table 2 for a panelboard indicates the value of a is 100 and k is 0.127. The previous calculations indicate that Idc arc = 11,433 Amps and Rarc = 0.00895Ω. The working distance, d is 457 mm and the duration, tarc is 0.3 seconds. These values can be used with the dc arc ﬂash worksheet for calculating the incident energy Electrical Review | May 2017
Except for two technical papers that are referenced in the Annex of NFPA 70E, dc arc ﬂash equations and calculation methods are not part of any standard - Yet! As research regarding dc arc ﬂash and dc source modelling continues, dc arc ﬂash calculation methods will likely become part of a standard someday. Until then, since no standard presently exists for dc arc ﬂash calculations, why would anyone perform them? You don’t have to look too far back in the history of arc ﬂash to ﬁnd the answer. Even though IEEE 1584 was ﬁrst published in 2002, some people were performing arc ﬂash studies and calculations for ac systems long before then. How could that be? By using the best-known methods and equations that were available at the time - and the same thing is happening once again today with dc arc ﬂash. Funny thing about history, it often repeats itself. Note: As with any analytical calculations or engineering study, only qualiﬁed persons should perform them.
REFERENCES: “Arc Flash Calculations for Exposures to DC Systems by D. R. Doan - IEEE Transactions on Industry Applications, Vol. 46, No. 5. “DC-Arc Models and Incident-Energy Calculations” by R. F. Ammerman, T. Gammon, P.K. Sen and J. P. Nelson - IEEE Transactions on Industry Applications, Vol. 46 No. 6. “Electric arcs in Open Air” by A. D. Stokes and W. T. Oppenlander - Journal of Physics D: Applied Physics 1991 “Simple Improved Equations for Arc Flash Hazard Analysis” by R. Wilkins - IEEE Electrical Safety Forum, August 30, 2004 “Complete Guide to Arc Flash Hazard Calculation Studies” by J. Phillips - Brainﬁller, Inc. 2010. “Know Your Arc: DC Arc Flash Calculations” by J. Phillips – Electrical Contractor Magazine, May 2015 Jim Phillips, PE, MIET is associate director for Electrical Safety UK. He is the founder of www.brainfiller.com and www.ArcFlashForum.com and conducts training programs globally on many electrical power system subjects as well as performs forensic investigations. Jim is Secretary of IEEE 1584 – IEEE Guide for Performing Arc-Flash Hazard Calculations and International Chairman of IEC Technical Committee 78 – Live Working.
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38 | ADVERTISEMENT FEATURE
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ith a history of operating in the Rail Industry for more than 70 years Craig & Derricott has developed a strong reputation as a manufacturer and supplier of Low voltage Control gear, Switchgear and specialist lighting. Involved within the rolling stock, overhaul and infrastructure sectors, the company is focused on providing high quality bespoke products and believes in working closely with clients designing and developing components and solutions to solve problems such as obsolescence which has become increasingly more problematic in the railway rolling stock industry. A prime example of Craig and Derricott’s ability to respond to market demand is its solution for the refurbishment sector following the government’s decision to make T12 ﬂuorescent lighting obsolete. “Our LED tube light solution has combined the needs of easy and safe tube ﬁtting with a unique solution to the electrical and mechanical protection of LED circuits within the dimensions of an existing tube light” says Business Development Manager, Jonathan Beaumont. “The LEDs have been utilised and adapted for the railway rolling stock sector while offering a variety of tube lengths and operating voltages to cover the needs of UK overhaul market” he continues.
Electrical Review | May 2017
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BLOG / OPINION | 39
Steer clear of steeper ﬁnes for health and safety offences Ian Hollingworth, head of claims for ECIC
n 2016 the UK Sentencing Council announced major modiﬁcations to the penalties for health and safety at work offences with ﬁnes set relative to the size of the business and the potential harm that could have been caused. This was to ensure they would have an ‘economic impact’ on the offending employer. The modiﬁcations followed concerns existing sanctions were too low to act as a signiﬁcant deterrent. One year on and, not unexpectedly, the number of ﬁnes imposed that are reaching six and seven ﬁgures for Health and Safety at Work offences have risen starkly. In some cases the level of ﬁnes may represent a massive 700% increase compared to the ﬁnes the business being prosecuted may have faced under the old regime. The modiﬁcations mean that some of the UK’s largest contracting businesses with turnovers exceeding £50m convicted of corporate manslaughter can now face ﬁnes of up to £20m. Furthermore, individuals such as company managers or directors who are found guilty of a breach in duty of care to their employees could face a custodial sentence of up to two years. Just to underline the scale of this change, in the year since the new guidelines were introduced there have been 19 ﬁnes of over £1m compared to 3 in 2015 and none in 2014. From an electrical contracting industry perspective what really concerns ECIC, as a specialist insurer in this market, is the fact that we have seen a signiﬁcant uplift in the frequency of HSE notiﬁcations in the past year, with around 4 times the number of that in previous years. In addition to this, many of our policyholders are classed as mid-sized electrical contracting ﬁrms under the guidelines (with turnovers between £10m and £50m) who, some could argue are disproportionately impacted by the new guidelines. Due to the wide bracket of ﬁnes under the new guidelines, £1000 to £4m, many mid-sized businesses may now ﬁnd themselves facing a ﬁne similar to that of a much larger company with much deeper pockets. Previously a £250,000 - £500,000 ﬁne was the range for the most serious offences under the old guidelines whereas now, dependant on the company’s annual turnover (as opposed to proﬁtability), the ﬁne could be as much as £10m for the exact same incident. What many contractors might not realise is just how much information the sentencing process takes into account. Firstly, the Courts are required to consider the level of ‘culpability’ ranging from low i.e. the company did not fall far short of the appropriate standard, to high i.e. a deliberate breach of, or ﬂagrant disregard for the law. Aggravating factors e.g. cost-cutting at the expense of safety as well as any mitigating factors such as a good health and safety record are then also considered at this point. The level of
harm in this process is then categorised on a level of 1-4 and refers to the potential harm that could have been caused rather than the actual injury sustained. Cases involving corporate manslaughter are classed as either Category A where incidents are indicated to have had a high level of harm or Category B, where a lower level of culpability has been established. The ﬁne imposed is then determined based on the annual business turnover. Without stating the obvious, the increase in the number of HSE prosecutions and the level of ﬁnes being imposed under the new guidelines means it’s crucial, now more than ever, that electrical contractors of all sizes ensure they have an effective and robust approach to complying with health and safety laws. They must also have evidence of this approach with each and every worker signing site speciﬁc health and safety assessment forms at the onset of each job to ensure they are aware of any risks, the control measures in place and personal protective equipment needed. In a recent survey we conducted amongst contractors, 1 in 4 ﬁrms failed to take this approach. A contractor with a neat folder detailing its health and safety practices and risk assessments may feel they have fulﬁlled their obligations but, if those documents were not provided to the employee that will not stand up in a court of law as evidence the claimant ought to have known about the risks and known what preventative action to take. This exposes the contractor to claims for civil damages and if serious enough a prosecution by the HSE which may lead to a signiﬁcant ﬁne or even imprisonment. The contractor must provide evidence that the worker read the risk assessment, understood the risks and signed and dated the Health and Safety policy document prior to them commencing the work. A signed, dated document is the crucial piece of evidence a contractor needs to demonstrate compliance with the relevant statutory duties of care and Health and Safety Regulations. Without a proper risk assessment detailing the risks and control measures shown to and signed by the workers involved, the contractor leaves themselves open for criticism by the courts in the event a claim is made for not taking all reasonable measures to protect their employees. The outcome of a Court prosecution could be immensely damaging not only on a ﬁnancial level, but on personal level for the company directors and the reputation of the business. EC Insurance Company Ltd (ECIC) is authorised by the Prudential Regulation Authority and regulated by the Financial Conduct Authority and Prudential Regulation Authority. FRN: 202123. https://www.healthandsafetyatwork.com/regulation/ sentencing-guideline-2015 Health and Safety Sentencing Guidelines One Year On Report by IOSH in partnership with Osborne Clark LLP, Jan 2017. www.electricalreview.co.uk
VOLTAGE OPTIMISATION | 41
Perfecting the electricity mix Dr Alex Mardapittas, managing director for leading energy storage and voltage optimisation brand Powerstar, discusses the company’s engineering based concept to completion solutions and how the two technologies, one modern and one long standing, can play a standalone or combined role in lowering electrical consumption and improving supply for buildings and facilities
ith growing reliance on data centres and critical IT equipment connected to the ‘Internet of Things’ (IoT), we are living in a world where electricity supply, more than ever before, is crucial to private and public sector businesses. Therefore, it is evident systems need to be protected, not only by security solutions, but also from the electricity which supplies the systems. Power supply quality issues, such as blackouts, brownouts, voltage spikes and dips can cause signiﬁcant damage to highly sensitive areas, such as data centres, hospitals, or even manufacturing and processing environments, where critical equipment must function correctly24 hours a day. In order to secure the power supply to vital electrical systems there are a host of engineered solutions which can provide full UPS (Uninterruptable Power Supply) functionality. Currently, many facilities use combined heat and power (CHP) units or generators to provide UPS. However, even though both provide energy off the grid and offer sufﬁcient back up power, they are ageing systems in a technologically advanced world. One of the most recent, and most discussed, innovations for UPS is battery-based energy storage technology. The solution, which is already deployed in many facilities across the world,
stores the energy provided by the National Grid at times of low demand, or directly from renewable sources, for use at peak times or when required. There are a host of beneﬁts that can be accessed by using battery-based energy storage technology for UPS. Storage batteries constantly monitor and measure electricity supply to the load and rapidly recognise when power is required. When support is triggered, the batteries will reply automatically within a three-millisecond timeframe providing electricity to the sensitive load during a period of two hours. The nature of battery-based energy storage technology also provides a ‘future proof’ solution for constantly evolving industries and critical locations, such as data centres. Frequent changes in the processing power and speed of IT equipment, along with a range of electrical equipment which is now connected to wireless controls, means there is a greater requirement for UPS solutions which can be scalable to match demand. Capacity can be added simply by installing and connecting additional batteries, which can be accounted for during the speciﬁcation process or once growing demand is recognised. In parallel to the requirement for UPS some of the most widely recognised and popular energy providers have been increasing www.electricalreview.co.uk
VOLTAGE OPTIMISATION | 43
tariffs for electricity use in both commercial and residential properties, even though Ofgem has recently reported that there is no clear reason why this should be the case. Alongside the rising costs from electricity companies, the National Grid is also compounding the problem for businesses that consume moderate to high levels of electricity by increasing DUoS (Distribution Use of System) and Triad tariffs. When it comes to signiﬁcantly reducing electricity consumption at periods of high tariffs, energy storage technology provides a tailored solution for facilities of various sizes. By allowing buildings to operate off grid, the technology can save an average of 24 per cent on electricity costs. A bespoke energy storage solution, which is engineered for a speciﬁc facility, can allow businesses to generate additional revenue by accessing Demand Side Response (DSR) incentives. Current DSR schemes offer a signiﬁcantly cheaper option than attempting to maintain a level of electricity use during high tariffs periods throughout the year. However, due to changes in the scheme, with the need for businesses to respond to grid challenges within a rapid timeframe, the speed of battery-based energy storage technology ensures a successful response to at least 95 per cent of all DSR demands. The ﬂexible nature of energy storage also allows the technology to be combined with existing energy saving solutions
on businesses’ sites, including voltage optimisation systems, in order to reduce electricity costs further, alongside improving power quality issues and supply. It is well documented that voltage optimisation is highly effective at reducing the over voltage supplied to buildings, whether it be a stable or unstable supply, which negatively impacts a facility’s energy consumption, increased electricity costs, higher levels of carbon emissions and early onset degradation of electrical equipment. More recently, the beneﬁts of voltage optimisation have been further conﬁrmed under laboratory conditions by American Electric Power (AEP) at the renowned Dolan Research centre. The report concluded that a well-designed and speciﬁed Powerstar voltage optimisation system can achieve average energy savings of 6.7 per cent, at a 15V reduction, while also improving the efﬁciency of the machinery it was tested on. In most new residential and commercial buildings, every measure is taken to ensure optimal energy efﬁciency, including insulation, double glazing, solar panels and low energy lighting. However, one area that is often overlooked is the amount of energy consumed by the electronic equipment used. It is clear that by using the latest engineered solutions and technology, businesses can access a host of energy saving beneﬁts alongside improving overall electrical supply and equipment efﬁciencies.
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SMART PRODUCT OF THE YEAR AWARD
DATACENTRE SOLUTION OF THE YEAR ACCOLADE
Product manager, Cornelius Plath, was delighted to accept the Middle East Electricity product award on behalf of Omicron and particularly, the team who worked on the Testrano 600 development. The award was made in the Smart Power Product of the Year category for Omicron’s new power transformer test system. Given that testing of power transformers is quite time consuming with different test sets, lots of re-connecting, and multiple trips up and down the transformer, Testrano 600 cuts testing time hugely as the three-phase source allows excitation of all three windings at the same time. This gives customers the ability to measure the voltage ratio and actual phase shift. In today’s economic environment time is a valuable resource for many of our customers. Therefore, Omicron’s vision to develop a test system which makes power transformer testing quicker and easier than ever before, has been realised.
Schneider Electric, the global specialist in energy management and automation, has won the prestigious ‘Datacentre Solution of The Year’ category at the European IT & Software Excellence Awards, 2017. The award, for an upgrade project delivered in conjunction with APC by Schneider Electric Elite Partner Comtec Power, a leading UK data centre design and build company, was facilitated to meet the differing needs of Cardiff University’s High Performance Computing (HPC), Advanced research (ARCCA) facility. The University worked with Comtec to design, populate and upgrade its data centre, which utilised components of Schneider Electric’s InfraStruxure (ISX) data-centre physical infrastructure solution in addition to high efﬁciency chillers and the StruxureWare for Data Centers: Data Center Operations Energy Efﬁciency software module.
Omicron electronics • 01785 251 000 www.omicron.at
Schneider Electric • 0800 2799 254 www.schneider-electric.com
MODELS WITH FM CONTACTS
Yokogawa is adding an entry-level model, the AQ1000, to its range of OTDR (Optical TimeDomain Reﬂectometer) test instruments. The new instrument joins the existing mid-range AQ1200 series and the high-end AQ7280 series, and is speciﬁcally designed to increase the productivity of ﬁeld personnel working on the installation and deployment of optical access networks such as Fibre to the Home (FTTH): the so-called ‘last mile’ to consumers’ premises. “The worldwide use of these optical access networks is increasing dramatically as telecom operators lay new FTTH network structure is to cope with increase in consumer demand for “super-fast” broadband and high deﬁnition TYV services ”, says Terry Marrinan, vice-president, T&M Business Unit, Yokogawa T&M Europe and Asia Paciﬁc.
The space saving combined Type 1 and 2 Lightning current and Surge arrester from DEHN is now available with volt free remote auxiliary contacts. High lightning current discharge capacity up to 50 kA (10/350 μs) – Fulﬁlls the requirements of BSEN62305 for Lightning protection classes III and IV Fulﬁls the requirements concerning the lightning current discharge capacity as speciﬁed in BS7671 of 12.5kA per pole Optional volt free remote signalling contact for remote monitoring Common green/red operating state/ fault indication for status indication of all arrester paths Compact lightning equipotential bonding and protection of terminal devices due to spark gap technology High follow current extinguishing capability (Iﬁ = 25 kArms) DEHNshield takes up only 4 standard DIN modules and is ideally suited for installations with restricted space.
Yokogawa • +31 (0) 884641190 www.yokogawa.com
Electrical Review | May 2017
Dehn UK • 01484 859111 www.dehn.co.uk
ANSWER THE DOOR FROM ANYWHERE WITH NEW WI-FI DOOR STATION Leading security products manufacturer, ESP, continues to expand its Aperta range of access control solutions with the launch of a brand new Wi-Fi Door Station. Aimed at the domestic market, it allows you to view and talk to visitors at your home whether you are on the premises or on the other side of the world. From a smart phone or tablet and using the free ESP app, property owners can easily see who is at the door or gate, engage in two-way communication and allow remote access if desired. The WiFi Door Station comes in a kit form containing everything required for the installer to quickly and simply get the system up and running, including the Wi-Fi door station, power supply, 10DB wiﬁ antenna, micro SD card (pre-installed) and LAN terminal. Requiring Wi-Fi or 4G, it is recommended that the door station is programmed prior to installation. For a successful set up, the installer much ensure that the user’s smart phone is connected to the Wi-Fi network, the Door Station is within the network’s Wi-Fi range and that the key/ password is available. ESP • 01527 515150 www.espuk.com
PRODUCTS | 45 FREE POWER QUALITY CPD-ACCREDITED WEBINARS
150W LED DRIVER
The second of Fluke’s series of free, scheduled, CPD-accredited webinars, running throughout 2107, is titled ‘Power Quality – The Good, The Bad and How to Measure’ and is suitable for Electrical Engineers, Plant Maintenance Facility Managers, and Energy Managers. Other topics covered by the CPD-certiﬁed webinar series include ‘Energy Saving – A Practical Approach to Energy Efﬁciency’ and ‘Detecting Electrical Energy Loss Using Thermal Imaging’ which are also aimed at personnel including Electrical Engineers, Plant Maintenance Facility Managers, Energy Managers, Electricians and Electrical Contractors. The repeated schedule of dates and the means to apply can be found at http://www.ﬂukeacademy.shuttlepod.org/ UK-Seminars.
Designed for 230V higher output luminaires such as high bays used in Europe, the Middle East and Asia, the new 150W LumoSeries LED driver like others in the LumoSeries range, features the lowest in-rush current in the industry which means that more drivers and luminaires can be operated on a single circuit, thus reducing the cost of installation with fewer circuit panels and less wire to run. The lightweight plastic-cased LED driver has compact dimensions of just 212 x 76 x 46mm for easy ﬁt within luminaires. Its high speciﬁcation includes a wide range of current settings from 700mA to 4A; output voltage 24 to 60V DC; and has 0 to 10V dimming which can be set for dimming to off at 1V. It also features thermal overload protection with internal or external NTC and there is a 12V fan power output also controlled by an NTC temperature sensor.
Fluke • 0207 942 0700 www.ﬂuke.co.uk
Fulham • +31 72 572 3000 www.fulham.com
BACK TO BASICS SMART SOLUTION Scolmore’s range of Click Smart intelligent wiring accessories aims to strip home automation right back to basics to offer a smart solution that has at its core, accessibility and simplicity for the installer and end user. The ‘Click Smart’ range provides a system that makes it easy, quick and relatively inexpensive to adapt and update a home to provide extra security, energy saving, comfort and control for homeowners and other occupants. The Smart Switches within the range make it easier than ever for installers to provide an upgrade to an existing wiring installation with minimal disruption. Adding an additional switch to an existing light without the need for cabling; solving the problem of continuous ﬂickering when you switch on one of your lights with a rotary dimmer (wired); and introducing two-way dimming control from separate locations (wired) are just three of the problems that can easily be solved.
Scolmore • 01827 63454 www.scolmore.com
SOFTWARE FOR EASY CONFIGURATION OF LUMINAIRES
HOW TO CHECK IF COOLING OUTPUT INSIDE ENCLOSURES IS SUFFICIENT Manufacturing automation systems are delicate and very expensive pieces of kit, which perform vital functions for the businesses they serve. The enclosures that protect them must have strictly controlled internal environments with interior temperatures that are carefully maintained within a few degrees. If not, the impact can be harmful to the inverter drives, power supplies, contactors, PLCs and other electrical and electronic components operating within them. This requires careful control of the climate within the enclosure. Like all electrical equipment, drives create heat and they therefore have a major inﬂuence on the temperatures inside enclosures. Drives are often quoted as having efﬁciency of 97 per cent, so one with a rated output of 150kW can produce as much as 4.5kW of heat. As well as the heat loss inside the enclosure, ambient temperatures within a production facility will also have an impact on the temperatures that a drive is operating within. Rittal • 01709 704000 www.rittal.co.uk
DRAMATIC IMPACT AT VALIANT BANK
Tridonic, a leading global provider of integrated lighting solutions has launched a new software for easy driver conﬁguration, deviceCONFIGURATOR, to allow customers to edit driver settings whilst reducing programming errors. The software can conﬁgure both Tridonic’s PREMIUM and EXCITE drivers and supports the DALI USB interface and the ready2mains programmer. The system has many advantages which include: Optimised work processes – deviceCONFIGURATOR ensures that production personnel can write the correct driver settings easily and precisely into the luminaire. This allows the new tool to make your conﬁguration processes more efﬁcient during production.
A new ceiling light spanning the counter hall at Valiant Bank, Bahnhofplatz in Bern has been backlit by Tridonic’s Tunable White LED technology to create a dramatic centrepiece. After eight months of refurbishment, the 1913 listed building has been totally refurbished by Rykart Architeken AG to bring the building up to present day standards. One of the major decisions of the project was to reinstate the light ceiling in the counter hall but instead of using daylight, the large format ceiling panels are backlit by Tridonic’s Tunable white which picks up on the dynamic properties of natural light but enables variable light colours to be created. To gain more ofﬁce space on the upper ﬂoors, the light ceiling was closed in the 1970’s but the refurbishment of the existing ceiling has included 36 light emitting coffers measuring 90 x 90cm each.
Tridonic UK • 01256 374300 www.tridonic.com
Tridonic UK • 01256 374300 www.tridonic.com
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Contact the sales team 0207 933 8974 Lighting
Electrical Review | May 2017