The Availon journal for independent wind energy service | January 2011
A “Gre Wa” r inpnt WTG r . In order to clearly communicate its future-oriented focus outwardly, SSB Service was renamed Availon. Discover more about the opportunities and benefits of a company where “availability” is already reflected in its name in an interview with the Availon GmbH management. Page 4
Availon: Our interview with the management. Page 4
ITEC: The specialist in wind turbine technology. Page 14
E.ON: Alternative discovered that increases availability. Page 17
Contents | January 2011 4
Cover article: A “Green Wave” for independent WTG service. Our interview with the Availon GmbH management. 8
Inspections: All inclusive or customized? 10
Oil quality, part 3: Fewer oil changes with kidney loop ﬁltration. 12
Independent Wind Turbine Service: A driver of real progress. 14
ITEC: The specialist in wind turbine technology. 17
E.ON: Alternative discovered that increases availability. 18
Lenord + Bauer: Exact determination of position and rotational speed during extreme environmental conditions.
IMPRINT Published by: Availon GmbH · Jacksonring 2 · 48429 Rheine · Germany Fon +49 5971 8025-0 · Fax +49 5971 8025-109 · www.availon.eu Edited and designed by: EXPECT MORE Kommunikation GmbH · Breite Straße 4 48431 Rheine · Germany · Fon +49 59 71 80 40 9-0 · Fax +49 59 71 80 40 9-100 · www.expect-more.de Responsible according to German press law: Availon GmbH Fotos: Ulrich Wozniak (p. 5–7), Fotostudio Scheiwe (p. 14–16), E.ON Climate & Renewables Central Europe GmbH (p. 17), Lenord, Bauer & Co. GmbH (p. 18) Copyright: All contributions (text, photos, graphics, logos and tables) published in ON Service are copyright protected. The copyright is owned by Availon GmbH, unless stated otherwise. Reprinting, storing in databases, on online services and Internet pages or copying onto data media is only allowed with prior written permission by Availon GmbH. Number of copies: 500
â€œS Îź c a asub vue.â€? Availon has been the new name of SSB Service GmbH since September 2010. Is it just a change of name or is there more to it? What are the strategies and goals of Availon? And why are they convinced that independent service providers are becoming increasingly important for owners and operators? ON Service put these questions to Ulrich Schomakers and Markus Spitzer, Managing Directors of Availon GmbH.
At Husum WindEnergy 2010 it was impossible to not notice that SSB Service had changed names. Why did you rename the company given the fact that SSB Service was already established in the independent wind turbine maintenance services industry and had a very good reputation? Ulrich Schomakers: In 2007, SSB Service was established in Salzbergen as part of the SSB Group. The three companies in the group provide very diďŹ€erent services, which made it necessary to diďŹ€erentiate between them. So the renaming is a clear separation between SSB Wind Systems as a provider of electrical systems for wind turbine generator systems, SSB Duradrive as a manufacturer of speciďŹ c drive solutions and Availon as an independent maintenance specialist for turbines. It was also impor-
Focus on tant to our customers that we clarify the independence and specializations of these three companies.
under one roof: from inspecting, completing maintenance and servicing rotor blades up to turbine optimization.
Markus Spitzer: Given the diverse requirements of our customers, we will continue to utilize the synergies between these companies in the future. Each company will, however, follow its own business and marketing strategy.
A second success factor is the establishment of standardized maintenance processes. Speedy and eﬃcient maintenance services can only be provided with absolute standardized, reliable processes. Our success in this area has been proven by the recent, and very positive Germanischer Lloyd certiﬁcation of the qualiﬁcation of our personnel, fault removal and repair processes for Vestas® turbines. We had already received a similar certiﬁcation in 2008 for GE® turbines. Germanischer Lloyd has also certiﬁed the management and implementation of on-site maintenance, as well as Availon’s analysis and documentation. So, our customers can be conﬁdent that they are working with a reliable partner certiﬁed by an independent institute.
Why did you decide on the name Availon and what does it stand for? M. S. : It is very important for us to send a message, beginning with our name, to our customers as well as to our employees. Availon is derived from “availability.” And maximum availability of a turbine continues to be the fundamental service we oﬀer our customers, because turbines have to run to achieve yields. This is a simple but signiﬁcant truth that motivates our team on a daily basis. The turbines have to be available, but we also have to be available for our customers at all times with considerable commitment and knowledge. Every customer should understand that we are available to them at all times, day or night. Our new name Availon positions our company, provides a mission for our employees and a ﬁrm promise to our customers. What exactly do you mean by a ”firm promise“? That turbines maintained by your company will achieve maximum availability? M. S. : Yes, that’s right. But how does Availon as an independent service provider achieve this ambitious goal? U. S. : Basically, the perfect combination of three main factors is crucial, one being the experience gained by our employees in the wind industry over the last few decades. The ﬁrst factor is absolute competency in regard to turbines and I really mean “absolute“. We only oﬀer servicing for speciﬁc turbine models once we are completely familiar with it. We have to obtain extensive technical knowledge and invest considerable energy and time into ongoing training for our employees. Our team includes engineers and technicians who have gained wind experience from leading turbine manufacturers. This helps us provide our customers with comprehensive and reliable expertise for each turbine model. Comprehensive service means doing it all
M. S. : The third factor is that we, as an independent service provider, must be able to optimize turbines to provide measurable positive eﬀects in their yield. In our opinion, maximum availability and a reduction of maintenance costs can only be achieved by continuously optimizing a turbine and by cost-eﬀective upgrades. This ensures the long-term economic eﬃciency of a turbine as an investment, which is very important to us. We maintain close daily contact with our customers in order to develop new eﬀective upgrades. Of course, developing new upgrades depends on having a detailed knowledge of the turbine as you have already pointed out. You have said before that you have a “step-by-step” process. What do you mean by this?
U. S. : Well, we started as an independent provider, oﬀering maintenance services for GE turbines in 2007, for which we already had all the required expertise. This was followed by our qualiﬁcation and certiﬁcation for Vestas® turbines and we now continue with Gamesa® and other makes of turbines. We are consequently expanding our turbine portfolio stepby-step by ﬁrst gaining the complete technical knowledge for a speciﬁc turbine model and for the implementation of the respective maintenance and repair work. It would be wrong to promise customers an increase in availability or a reduction of operating costs without having the knowledge of how to actually achieve it. We have to oﬀer transparent processes and services that are understandable for the customer and that also stand up to independent testing. We therefore always strive to achieve a level of expertise and quality of service that is audited and certiﬁed by Germanischer Lloyd. In the meantime, you have extended your portfolio to include Vestas® and Gamesa® turbines and have received expert certification for 2 MW turbines of type V66 VCS®, V80 and V90 from Germanischer Lloyd. M. S. : Yes, during Husum WindEnergy 2010, GL Renewables Certiﬁcation qualiﬁed the introduction and implementation of more Availon quality assurance measures. The certiﬁcation applies to the operational management of the integration of Vestas® turbines into existing processes. As part of the current certiﬁcation, GL analyzed the maintenance and repair strategies, the fault and repair processes and if Availon personnel are qualiﬁed for maintaining Vestas® turbines. GL placed special emphasis on ensuring personnel were qualiﬁed, thus certifying the Availon training program.
“ Vestas” and “VCS” are registered trademarks of Vestas Wind Systems A/S, DK. “Gamesa” is a registered trademark of GAMESA CORPORACION TECNOLOGICA, S.A., ES. “ GE” is a registered trademark of GENERAL ELECTRIC COMPANY, US
Markus Spitzer, left, and Ulrich Schomakers, Managing Directors of Availon GmbH.
Long before offering services for Vestas® turbines, the company opened a Competence Center in Norderstedt near Hamburg.
What new developments or upgrades have resulted from the work of the Competence Center?
U. S. : That’s right. One of our core tasks is to proactively provide a clear added value for our customers by optimizing turbines and reducing costs. The entire knowledge of Vestas® turbines started in our Hamburg Compe-
M. S. : One of the most signiﬁcant recent developments is a new generator for 2 MW turbine models V66 VCS®, V80 and V90 for which we used the aforementioned synergies with SSB Duradrive. Because of its construction and
shaped-wire windings, while the insulation is applied using the VPI (Vacuum Pressure Impact) process. This provides a high level of protection for the windings and a seal free from voids ensuring a power output that will remain constant over the years. The windings comply with insulation class F. The machine can therefore be continuously operated up to a maximum winding temperature of +155° C. The use of high quality materials of insulation class H (+180° C) increases the service life of the generator, when used according to F standards, even under demanding conditions. Are there any other improvements? U. S. : Yes. For V80, V66 VCS® and V90 turbines, we oﬀer a rotor cable replacement for the generator. Overheating of the original cables causes irreversible damage and thus loss of revenue. We replace existing rotor cables with the latest generation of cables featuring a greater cable cross section and providing improved stress resistance, ensuring the smooth operation of the turbine, even during high-wind periods. As an independent service provider you have the advantage of being able to communicate more openly with customers and act more freely than an OEM (Original Equipment Manufacturer). What concrete benefits of choosing an independent service provider would you name if asked by an owner or operator considering Availon?
tence Center. We opened it in August 2009, to develop speciﬁc servicing and maintenance strategies. The Center produces, for instance, in-house maintenance instructions that often exceed the safety and eﬃciency standards of the manufacturer. The instructions and respective manuals are certiﬁed by an independent body. Our Norderstedt team also has comprehensive detailed hydraulic, electrical and mechanical knowledge, allowing us to implement eﬀective optimizations even on critical components or technically vulnerable individual systems.
length, as well as the special design of its stator and rotor, the machine is completely unique. Why is that? U. S. : Special features of this new development include, among others, a high-speed variability, optimized stator and rotor windings, including heavy-duty insulation, greater protection of the roller bearing against bearing currents, optimized protection of the slip ring body against soiling and an eﬃcient cooling concept. The stator and rotor of the new generator contain
U. S. : I would like to emphasize once again: Our main goal is to provide a signiﬁcant added value for turbine operators and to achieve a high level of availability for their turbines. That is how we measure our performance. We oﬀer a high level of commitment and operational readiness. We are responsive, reliable and very ﬂexible, which allows us, for instance, to resolve problems within the shortest possible response times. As an independent company we also have the advantage of more freedom when sourcing spare parts. We compare prices and, naturally, the quality to ensure our customers obtain the best solutions at a fair price – even at short notice, when necessary. We have constant access to alternative suppliers or to spare parts developed by ourselves and realized with partner companies. We regard ourselves as a partner with the same aim as our customers. We consequently provide completely independent advice, openly discuss weaknesses of turbines and oﬀer suitable optimizations. Our
In our interview with him, Markus Spitzer outlines the benefits of independent service providers.
sound analysis provides operators with an objective and clear overview of the condition of their turbines at all times. We oﬀer all our customers a wide range of contractual options from which they can compile their individual service agreements. Figuratively speaking, customers order the music from us and we put together the orchestra according to their wishes. In other words: Our priorities are customer focused, customer focused and customer focused again. I would like to return one more time to the term “independence”. Do you have any practical examples demonstrating the advantages of an independent service provider? M. S. : Certainly. Take the example of urgently required repairs on a turbine, coupled with little ﬁnancial leeway. In this instance, standard repair methods are rarely inexpensive. Our task is to look at these methods and develop a maintenance solution of a similar technical quality but that is more cost-eﬀective. By using new repair methods and avoiding dismantling major components, we have been able to, for example,
save tens of thousands of Euros during a complete refurbishment of 1.5 MW turbines. It is worthwhile looking at alternatives before commencing work using theoretically proven standards. As an independent company we have the capacities and the knowledge to do this. U. S. : What’s more, we also have the knowledge required to provide less expensive and better technical solutions in case where an OEM could normally only oﬀer the replacement of a component or of a complete system. A good example is the defective obstruction light system of an entire wind farm, which normally would have to be completely replaced at very high cost. Our engineers have found an individual solution that no longer requires a complete replacement and that provides a system with long-term reliability and considerable cost savings. Such experience is not only valuable to us, but also to our customers, and clearly demonstrates the diﬀerence between an OEM and an independent service provider. Under the new name of Availon you are consistently expanding your international strategic position as an independent service provider. What are your intentions? U. S. : We have positioned ourselves as an independent provider of maintenance services for turbiness in Europe where we are the leading provider for turbines in the multi-MW class, and in North America . Our complete service concept in Germany, as well as in Spain, Italy, the USA and other countries has proven to be highly successful. There are enormous demands in the international markets. We have therefore set very high expectations within the company. But I think we are successfully meeting these lofty goals because we understand the wishes and priorities of our customers and act in the same way as our customers would. We actually see ourselves as their partner. Availon therefore oﬀers concrete and goal-oriented solutions that provide precisely what our customers want. Improved availability for each turbine and reduced maintenance costs really help our customers. Positive feedback from our customers, independent operators and major investors underlines that we have adopted the right strategy. At the same time, satisﬁed customers are an enormous motivation for us to become even better. For us, there is no upper limit to what is technically achievable in the wind energy sector. Thank you for the interview. “ Vestas” and “VCS” are registered trademarks of Vestas Wind Systems A/S, DK.
All inu or omized? Be honest. Have you been able to find an independent service provider able to offer a complete turbine inspection and allow you the flexibility of selecting individual services from an extensive service portfolio? You don’t think such a provider exists? Think again!
and gearbox. A visual inspection of the base frame for damage can already reveal visual cracks. Magnetic particle testing as part of the inspection can also detect changes to the structure. Generally, however, a diﬀerentiation must be made between tests carried out on castings and on welded units. A welded base frame is checked from the rotor to the generator. Such an inspection focuses particularly on hotspots (highly stressed areas of the frame). The inspection of a cast frame, on the other hand, focuses on checking the welded generator supports.
If you think about all the parts of a wind turbine requiring a full inspection, it becomes apparent why only very few service providers are able to provide such a comprehensive service.
Inspection of rotor blades. A regular inspection of rotor blades and repair of surface wear improves turbine yield. A visual inspection of the rotor blades requires the experience of a well-trained maintenance person in order to properly recognize cavities, cracks, erosion or other damage. A visual inspection also requires rappelling or a lifting platform that extends along the entire height of the turbine.
A visual inspection is not enough. During regular inspections, the turbine components are only visually checked and their condition is evaluated based on visual characteristics. This method makes it diﬃcult to achieve a detailed, objective and, therefore, more in-depth description of the condition of the turbine. In order to implement eﬀective preventive measures for maintaining turbine components, an inspection must extend beyond a visual check. Inspections start at the base. Due to the increasing frequency of damage to turbine foundations in recent years – sometimes massive damage – operators have become increasingly interested in the topic of foundation inspections. In the process of such an inspection, the foundation is visually checked for cracks and water ingress, as well as whether or not components have become loose, and pose a safety risk. For turbines with foundation anchor bolts, the adequate condition of grouting joints is, among other things, checked during inspections. Naturally, these are only a few examples of the work necessary for an inspection of the turbine base and for which, in some cases, the use of sensitive sensors is required. Inspections in the nacelle. In the area of the nacelle, regular inspections should be carried out on the base frame and on the machine itself, e.g., the generator, transformer
Modern measurement technology for gearbox inspection. Modern measurement equipment is required for the inspection of the gearbox. Gearbox bearings are, in some cases, hidden from view or located deep inside the gearbox. Such areas can only be inspected to a limited extent through inspection doors or cannot be viewed at all. A video endoscope allows inspection of nearly all areas of a gearbox and a determination of its condition. All bearings installed in the gearbox, the meshing of the gears and the position of the generator can be checked using a frequency measurement. In addition, reoccurring safety inspections have to be carried out on the turbine in order to assess the overall condition of the turbine and the safety of its components. Importance of expertise. In contrast to maintenance work carried out in accordance with a maintenance log and therefore based on precisely deﬁned speciﬁcations, the above examples clearly show that a thorough technical understanding of complex processes is an important prerequisite for a complete turbine inspection. Also important is an understanding of the interaction of the individual components within the overall turbine, thus necessitating specific expert knowledge coupled with the latest measurement technology.
Many specialists. For these reasons, operators generally commission several diﬀerent companies, each of which specializes in a particular area of expertise. This is a time consuming process, starting with an evaluation of the various service provider estimates and the coordination of diﬀerent call-outs. It also includes the administration of a wide variety of documentation for the completed inspections. When the need for repairs or potential optimizations becomes apparent during the course of an inspection, the situation becomes even more complex. “You only get what you need. ” This type of Sisyphean task is no longer necessary when there are independent service providers who oﬀer a full service package for turbine inspections. It is even better when the provider oﬀers the customer the opportunity to select individual services to meet his par ticular requirements. The advantages for the operator of such a modular inspection are indisputable and can be simply expressed as: “You only get what you need.” Potential cost savings. Here are a few concrete examples: If a rotor blade inspection was recently completed, or if the operator decides that an inspection of the foundations is not necessary, he can remove this service from the inspection agreement with his independent service partner. Another tangible example would be that the operator decides to not do a gearbox inspection due to an existing Online-Condition-Monitoring system report. By taking advantage of such a ﬂexible concept, the
operator can individually select inspections that fulﬁll his needs. The result? A potential for considerable cost savings. Minimum administrative work. The operator also receives detailed and, more importantly, uniform documentation about all inspection services. This documentation can also contain recommendations for optimizing the turbine, depending on the inspection carried out. The administrative eﬀort for the operator, as well as the planning of further measures, is in this way reduced to a minimum. Possible acceleration of damage claims. In case of damage, operators are also able to provide any required proof of regularly implemented inspections to an insurance company in the form of detailed documentation. This may improve the speed of damage claim settlements by an insurance partner. Flexible concept with add-ons. When modular inspections provided by an independent service provider are supplemented by upgrades that result in considerable improvements for the turbine, such as increased availability, a ﬂexible concept becomes even more attractive. Summary: The importance of regular turbine inspections is hardly a subject for debate among operators. What remains open for decision, however, is how much time and money you are willing to invest to get qualiﬁed, on-demand inspection services and in addition, deciding on which services you prefer or need.
Service technicians at a tower base and rotor blade inspection.
Oil qui, pt 3:
Few oil s wi kidney loop ďŹ Đž. 3 Îźm Oil
The quality of the oil is a decisive factor for the service life of a gearbox. In addition to the type of lubricants used, (e.g. synthetic oil with improved lubricating properties to extend service life) a new upgrade offers further potential for optimizing the oil quality and thus its service life.
2 Îźm Bacteria
Filter change according to level of wear.
Total particle amounts
The wear of a gearbox is determined by operating conditions and stresses exerted on the gearbox components. Gear oil life is therefore not linear and diďŹƒcult to estimate. Impurities, the degradation of additives and oil aging products produced during operation, all contribute to the premature aging of the gear oil. The new kidney loop ďŹ ltration upgrade improves oil quality and prevents the need to perform some ďŹ lter and oil changes recommended by the manufacturer, thus reducing downtimes and some costly repairs. Filtration up to 3Îź. This upgrade was specially developed for systems with a ďŹ ne ďŹ ltration level of 10Îź or greater. As the name of this new development already indicates, the kidney loop ďŹ ltration provides a separate oil ďŹ‚ow to clean the gear oil independently from the main ďŹ‚ow ďŹ lter. Oil aging products and particles larger than 3Îź are removed from the lubricant. At the same time, any moisture contained in the oil is absorbed by the ďŹ ltration. Contrary to common opinion, ďŹ ner ďŹ ltration systems do not ďŹ lter out additives â€“ these remain in the gear oil. The upgrade consists of a compact pump/ďŹ lter unit, installed by the gear coupling or on the gearbox itself. The oil is siphoned oďŹ€ from the lowest point of the gearbox through a hose, is cleaned inside the unit and is then returned to the gearbox.
8 Îźm Carbon dust
100 90 80 70 60 50 40 30 20 10 0
Visualization of particle distribution in oil (e.g. in hydraulic or gearbox oil)
25 Îźm Pollen
Feature 11 100 μm Grain of salt
40 μm Still visible to the naked eye
70 μm Human hair
Installing the kidney loop ﬁltration system only takes about four hours. The amount of time between ﬁlter exchanges is dependent on the degree of gearbox oil contamination. However, the required purity class of the oil according to DIN ISO 4406 diﬀers between gearbox manufacturers. The evaluation of oil analyses based on oil samples taken at regular maintenance intervals has shown that, during regular operation, a standard gearbox has an oil purity class of 22/20/17 (see ON Service, issue 9-2009, pages 8-10), which is usually a higher degree of soiling than speciﬁed by the manufacturer. After the initial installation, it is recommended, that the oil ﬁlter of the kidney loop ﬁltration unit be replaced after six months and then at 12 month intervals. The ﬁlter can be replaced during normal maintenance work, depending on its wear. Frequent oil changes are a thing of the past. This upgrade is immediately available and allows a more eﬃcient cleaning of the gearbox oil to enhance the service life of the oil. Most manufacturers recommend a maximum of 36 months between gear oil changes. In some cases, the service life of gear oil is not met due to impurities, causing a premature failure of the main ﬂow ﬁlter element. Comprehensive research has shown that only a small percentage of the dirt holding capacity of the main ﬂow ﬁlter element to absorb impurities was achieved, which was sometimes due to a deposit of oil aging products which formed a seal over the main ﬂow ﬁlter, causing its failure.
Thanks to kidney loop filtration, frequent oil changes are a thing of the past.
Longer changing intervals. The use of the kidney loop ﬁltration unit can extend the interval between gear oil exchanges to 60 months or more, saving considerable costs associated with frequent oil changes. Filter changes between regular maintenance intervals are also no longer required after installing the upgrade; the planned service life of the ﬁlter elements is achieved. Particularly in low wind
years, minimizing costs, maximizing eﬃciency and extending the life of such components is crucial. Well-known manufacturers of turbines already include kidney loop ﬁltration units in their new turbines and state that the oil change interval depends on the result of an oil analysis. Further information about the upgrade is available at www.availon.eu.
Inpnt Wind T!"ne S : A d#$ of p%g ss. Any damage to a turbine is frustrating, causing unwanted outages that contribute to yield loss. Damages often result in considerable repair costs or, in the worst case, the need for complete component replacement, resulting in considerable investment. Over the long term, upgrades can prevent costly problems such as those mentioned. The development of a new generator and optimized generator rotor cables by independent service providers demonstrates that they are decisively innovative.
During the development of a new 2 MW Vestas® and Gamesa® turbine, special emphasis was placed on achieving the “beneﬁts” of an improved design and, in return, reliable operation and long service life. The special features of the double-fed asynchronous generator of type DALFI-1979 include compatibility with diﬀerent makes of generators, high speed variability and optimized stator and rotor windings with demanding insulation. Greater protection of the roller bearing against unwanted harmonic currents, optimized slip ring protection against contaminants and an eﬃcient cooling concept are also special features.
Pure performance: Asynchronous generator Type DALFI-1979.
Constant power output for years. A vital part for ensuring the reliability of such a machine is the design of the stator and rotor windings, as well as their insulation. Due to this fact, the stator and rotor of the DALFI-1979 were developed with shapedwire windings, and insulation was carried out using the VPI (Vacuum Pressure Impact) process. This concept ensures a void-free seal, oﬀering a high level of protection for the windings, and ensuring constant power output over the years. Even under demanding conditions, the service life of the generator increases, as the newly insulated class F windings allow for operation up to +155 °C. The insulation material even complies with insulation class H, providing the machine with a maximum theoretical thermal stability of +180° C.
Changes 133 Developed a thicker skin: The new generation of rotor cables have expanded cable cross sections.
Optimum adaptation. Since the manufacturer-independent machine allows switching from star to delta operation, considerable speed variability and thus optimal adjustment of the machine to existing wind conditions is achieved. In the star operation, the generator is loadable up to 1,000 kW and in the delta operation up to 2,000 kW. But the new generator impresses not only in regards to output and speed variability. New roller bearing protection design. The development of a new roller bearing protection design took into equal consideration the value of reliability and cost eﬃciency. Due to their special design, the roller bearings feature an improved, insulated seat, preventing issues such as the destruction due to unwanted harmonic currents. Apart from facilitating installation and repair, the new concept also reduces potential subsequent costs.
Better protection against contaminants. In order to maximize eﬀective cooling and protect the slip ring assembly from contamination, an external air exhaust and ﬁlter was added. This greatly reduced the risk of short-circuits and punctures from extensive contamination. Efficient cooling system. Three separate external 3 kW asynchronous motors drive the cooling unit to achieve optimum cooling even at partial load, irrespective of speed. The new generator has been certiﬁed by Germanischer Lloyd (an expert assessment based on type testing) for use in the V66 VCS®, V80 and V90 2.0 MW models and the G80 to G90 2.0 MW models. Not only the generators, but also individual turbine components, such as the cables, are exposed to considerable stresses during operation.
Damage from overheating. Overheating of the generator rotor cables area often causes irreversible damage. Symptoms of overheating can be detected during visual inspection, but the replacement of damaged cables will be inevitable. Preventing risk from the start. The risk of overheating can be avoided from the start by replacing such cables with rotor cables with a larger cross section. Specially developed tools and working processes allow the rotor cables to be replaced directly in the turbine without using a crane. These upgrades are available immediately. More information is available at www.availon.eu.
“ Vestas” and “VCS” are registered trademarks of Vestas Wind Systems A/S, DK. “Gamesa” is a registered trademark of GAMESA CORPORACION TECNOLOGICA, S.A., ES.
“A &r in'(о @ *mpi+ - ;k in-p look @ wind =r"ne > @logy!“
Why a leading management company believes in independent maintenance services. Founded in 1998 and registered in Leer, Germany, the ITEC International GmbH initially took on the technical management of a wind park in Brandenburg, oﬀered as part of a renewable energies fund managed by the GHF (Gesellschaft für Handel und Finanz mbH). Today, ITEC operates as an independent, technical and commercial management company. ITEC International works with Ventotec GmbH – one of the largest German project planners in the area of renewable energies and uses independent service providers (ISPs) for maintenance and repair work on wind turbines. ON Service asked ITEC International Technical Director, Helmut Claassen and Director of Sales, Gernot Knipper what they expected from such service providers. What services are you currently offering? Gernot Knipper: Together with the project planning company, Ventotec GmbH, we form a powerful alliance in the area of regenerative energies with an emphasis on wind energy. The synergy between the two companies results, above all, in clear beneﬁts for our customers. We provide the full range of services – from planning and commissioning up to the operation of wind turbines. As part of our management services we not only provide technical support for the turbines, but also oﬀer competent commercial management to ensure the long-term economic success of projects. In addition, we develop concepts and solutions with our customers that are tailored to their requirements. Naturally, we oﬀer our management services to any operator – up to or also starting from the commissioning stage, irrespective of the project planner. How many wind farms do you currently manage? Helmut Claassen: We are currently managing 40 wind farms with a total output of 420 MW. This corresponds to 248 turbines, predominantly located in Germany but also in France.
When it comes to him, everything revolves around numbers: Purchasing Manager Gernot Knipper, ITEC International GmbH
workmanship, reliable maintenance cycles, transparent processes and a designated contact person. In our opinion, all of these factors form the basis of what we expect from a reliable ISP. These are justified but, at the same time, considerable expectations. To date, what have been your experiences in this regard? G. K. : ISPs have established themselves in the areas of maintenance and servicing, so that turbine operators currently beneﬁt from healthy competition and less dependency. The result is a better price structure. But, even more important is the increased quality, which we have noticed among ISPs, in the area of service processes and maintenance concepts, for example.
How many employees does your company have? G. K. : Our company has eight commercial and ten technical employees, including qualified businessmen, managers, engineers, as well as insurance experts, master craftsmen, etc. In addition to this highly qualified team, we work with about 20 service providers operating as turbine attendants at various wind farm locations. In this way, we ensure a high quality standard for our customers. In the area of technical management you cooperate with independent service providers. What do you expect from these partners? H. C. : First of all, we expect well-trained employees in the areas of servicing and maintaining turbines. The partner must also have received the necessary training qualifying them to provide maintenance services for diﬀerent types of turbines. Naturally, a high level of availability on the side of the service provider, easy access and quick response times are of utmost importance for us. Also indispensible in this context is excellent
What do you mean precisely by the statement that “ISPs have established themselves”? G. K. : Such service companies can be regarded as full-ﬂedged partners, as their services are by now equal to those of turbine manufacturers. Today, independent service companies are being taken seriously in the wind sector. As a result, turbine manufacturers are increasingly anxious and striving to convince their customers that they are reliable partners by providing better service. H. C. : This is a welcomed development, as customers are once again the focus and beneﬁt from improved maintenance and service concepts. In contrast to a turbine manufacturer, a service provider can generally act much more independently. As a result of this independence, the communication with such a partner can be much more open and transparent, for instance, as it relates to the planning of potential improvements to turbines.
Speaking of turbine improvements, how do you rate the ability of an ISP to develop upgrades in-house? H. C. : This ability is very important for us, because it is naturally also our task to increase the availability of turbines and to secure their value as an investment in the long term. In particular in older turbines, upgrades produce clear improvements in performance and reduce unwanted incidents. G. K. : … we also ﬁnd that just like turbine manufacturers, ISPs, regard the optimization of turbines as a necessity. For me, the fact that ISPs contribute their own suggestions for improving turbines is a clear indication that they have looked at wind turbine technology in depth and have applied their long-standing experience. H. C. : That’s right. I also think it is very important that we feel like we are in good hands with such service providers, since we entrust them with valuable assets. As operators we are, after all, responsible for capital goods with a high intrinsic value and must, in the interest of our customers, be He knows what matters: Technical Manager Helmut Claasen, ITEC International GmbH
Partial list of services oﬀered by ITEC International GmbH: Commercial management • Accounting and contracting • Controlling, budget planning • Liquidity planning, payment transactions • Reporting, client-focused reporting (annual and business reports) • Insurance management
Technical management • Remote monitoring with back-up data storage • Monthly technical reporting, analysis of performance data • Rapid response due to on-site support • Depiction of progress of damage • Monitoring of maintenance and inspection dates • Drafting of service and maintenance agreements • Coordinating and monitoring the replacement of large components Contact: firstname.lastname@example.org
proactive in ensuring a return on investment. Therefore, I welcome more involvement on the side of ISPs, even during the development processes of turbine upgrades. Because of their independence, they are able to act more autonomously and can also dedicate more attention to customer needs. Turbine manufacturers tend to use more standardized processes in this context, leaving less room for individual wishes. What are your plans for the future? G. K. : The ITEC International GmbH will continue to expand. At the beginning of 2011, we will have taken over the commercial and technical management for more turbines with a total output of 40 MW. We are also in the process of negotiating several new projects. H. C. : We are, therefore, very optimistic for 2011, with Germany still predicted to have a growing market. At the same time, we are not forgetting the other European countries. We are already talking to turbine manufacturers and independent service companies to develop eﬃcient service and maintenance concepts for potential locations. Thank you for the interview.
A n@ i 's*$ed @ inc a s aEiH"J Why E.ON decided to commission an independent service provider (ISP). E.ON Climate & Renewables has been operating the Schnellin wind farm in Saxony-Anhalt since 2003. In 2008, the company considered commissioning an ISP to carry out the repair and maintenance of the wind farm. ON Service asked Georg Persigehl, Head of Operational Management for Central Europe at E.ON Climate & Renewables about the reasons behind this decision, and his experience using an ISP. How many turbines are managed by E.ON Climate & Renewables in Central Europe? Georg Persigehl: Onshore alone, our company operates some 480 MW of wind power installed under contract in Central Europe. These include the turbines (wind turbine generators) in the Schnellin wind farm in Saxony-Anhalt. Why did you consider using an ISP for servicing and maintaining the turbines? We were not satisďŹ ed with the maintenance services provided by the turbine manufacturer. I often had the impression that our interests as a customer were not always taken seriously. Therefore, we decided not to be
solely dependent on the manufacturer and looked for alternatives. What alternatives were available? After we had made the decision in 2008 to become less dependent on manufacturers, we brought the ISP Availon on board. We agreed to a one-year test phase with the company, during which time we were both committed to accumulating knowledge about servicing and maintaining the turbines. What were your expectations for Availon? First of all, it was decisive that the ISP be able to ensure the availability of spare parts for type V80 turbines. The company also had to prove that it had the technical knowledge required to maintain and service the turbines. What experience did you gain during the test phase?
Already, during this one-year test phase, Availon managed to carry out all maintenance and service work on the turbines in an extremely positive way. The result was that the availability of the wind farm increased by 1.3 percent during this time period. â€Ś and that has made it easy for you to make a decision after the test phase? Certainly, because it was clear that we had made the right decision in terms of generating a certain competitiveness in the servicing market. In this context, Availon impressed us tremendously by showing that it was highly competent in the full maintenance and service work of our turbines and had the technical abilities necessary to sustainably increase the availability of the turbines within a short period of time. What agreements have you made with Availon based on this positive experience? We signed a maintenance agreement with Availon in April 2010 that also includes remote maintenance of the Schnellin wind farm turbines. According to the agreement, troubleshooting and other service work will be commissioned separately. Thank you for the interview.
Georg Persigehl, Head of Asset Management for Central Europe, E.ON Climate and Renewables
P Kо is of vital impor;n .
ReqL Mʦ r QmiUng e poо d %;о speed of wind =r"n+. In order to determine the precise position of rotating components in turbines, numerous sensors are needed to record rotation angle and speeds. These sensors must function reliably to efficiently utilize wind conditions and ensures long-term availability of the turbine, even at offshore locations. An article by Dirk Fedder, Sales Manager Renewable Energy, Lenord + Bauer
Because of extreme environmental conditions, considerable temperature ranges, diﬃcult to access oﬀshore locations, and service call-outs becoming more and more costly, so high-quality technical components with mechanical stability and optimized product life cycle are required. An in-depth analysis of rotary mounted turbine system components, often using rotary encoders, makes clear the requirements for the sensor system. Although from a physics point of view, wind energy is gathered mechanically, eﬀective utilization of this energy is only possible by using state-of-the-art sensors. Speed and position sensors are, therefore, installed in the nacelle, rotor hub, yaw and blade root as well as in the generator. The long-term use of conventional measuring systems in turbines is particularly complicated due to shock and vibra-
A three-track contour disk provides a high level of accuracy.
Topic 19 A turbine has numerous rotary mounted components, which positions and/or speeds need to be monitored.
The absolute position encoders GEL 235 are available with different types of flanges and interfaces to connect to modern machine controls.
tion stresses, contact with debris and lubricants, and in some cases, salty air combined with a high level of other contaminants. Although optical sensors oﬀer a high level of resolution and accuracy, their use is limited due to changing temperatures and vibrations. Magnetic sensors, on the other hand, using pole wheels or direct sampling of a diametrical magnet, often oﬀer insuﬃcient accuracy and resolution. They are, however, suitable for tough environmental conditions. Lenord + Bauer have developed rotary encoders for such conditions, combining the high-level of resolution and accuracy of optical systems with robustness and reliability. Based on the Nonius algorithm, the absolute encoders use the non-contact magnetic sensor of an encoding disk made from ferro-magnetic steel, the so-called contour disk (Figure 3). Magnetic-resistive sensors scan three tracks for this purpose, supplying three corresponding sinusoidal
signals that are unique along one rotation. Based on the Nonius principle, the phase position is determined and the absolute position is established with a high level of resolution and accuracy. Because of their mechanical design, the rotary encoders operating with the contour disk are shock, vibration and moisture resistant. The favorably selected extension coefﬁcients of the optimized design produce a very high accuracy of repeatability of the rotary encoder across the entire temperature range of - 40°C to +105°C. As a result, these encoders are particularly suitable for various wind energy applications. Rotary encoders have made it possible to replace optical absolute encoders with a robust magnetic measuring system, oﬀering a superior level of resolution and accuracy.
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