Norbert Weiss and Carsten Edler, HARTING ELECTRIC GmbH
Germany’s roughly 30,000 wind turbines currently produce a good 50,000 megawatts of electricity for households and companies. The expansion of wind energy both onshore and offshore is helping determine the pace and success of the shift in energy policy introduced at the beginning of the decade – a move away from nuclear power (NPP) towards renewable energies and reduced energy consumption.
For installers and operators, profitability and efficiency are of paramount importance when it comes to site preparation, installation, operation and the maintenance of wind turbines. These factors determine the level of investment and operating costs (CAPEX/OPEX) – and ultimately determine the economic impact a wind power plant can provide. Plants which are down produce no energy, receive no feed-in tariffs, and leave their potential to generate revenue untapped.
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Figure 1: Levelized cost of electricity
The HARTING Technology Group is one company that is heavily involved in accompanying the transformation under way in the energy sector. The company’s product portfolio ranges from single components through complete customer-specific solutions and digitisation strategies. These offerings also include consulting and services, thus providing the basis for long-term and secure investments in this sector.
Wind turbines are subjected to extraordinary stresses both onshore and offshore due to the particularities of the respective location, climate, corrosion and other environmental influences. Creating the foundation for maximum value retention of these systems takes optimal reliability, the best materials, high mechanical robustness of the components that are used, rapid assembly, optimal maintenance cycles and servicing that is simple to perform.
Connectors help reduce the costs of erecting and operating wind turbines. Modular wind turbines are characterised by flexibility of design and rapid component switch-out. Connectors can significantly increase the modularity of these facilities – and more and more wind turbines are being designed accordingly. The pre-assembly of individual units makes the modular concept possible. Components are quickly and easily joined together only at the final location of the wind turbine, meaning that flexible and reliable connectors are of vital importance to their design.
Using connectors to bridge wind turbine modules can limit the monetary and personnel costs accrued during installation and operation of wind turbines. A good example is connectors at the interface between the slip ring body and stationary nacelle. The slip ring is used to e.g. transmit the signals for the pitch systems that determine the angle of incidence of the rotor blades. A pluggable design – for example HARTING’s Han-Modular contact inserts and the Han-Modular hinged frame– offers many advantages over permanently attached wiring. For example, the slip ring can be replaced more quickly, thereby reducing downtimes and minimising revenue loss. In addition, if servicing is required, the slip ring can be replaced without intervention in the pitch system and without dismantling the connecting cables.
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Figure 2: Slip Ring
The drives for rotor blade adjustment, blade heating, lighting systems and yawing, as well as the generator brakes, can also be connected simply. Complex wiring is no longer required. In the event of maintenance, worn parts can be quickly and easily replaced in plug & play fashion. Connectors also facilitate the work of the assemblers, which sometimes need to install components in difficult-to-reach angles on the gondola and tower.
Many types of wind turbine employ a gearbox to tune the speed and torque between the rotor and the generator and thus optimise efficiency. Connectors speed up installation here as well: pre-assembled cables and connectors with a high degree of protection, for example the connectors from HARTING’s Han Eco, Han HPR or Han M quickly make the necessary connections between the gear units.
Using HARTING connectors also offers advantages for tower lighting. The energy bus elements for the lighting can be pre-installed in the tower segments. At the construction site, fitters only need put the segments together. Electricians do not necessarily need to be used for this activity. Other areas where connectors can simplify handling include the interior areas of wind turbine power cabinets. Instead of the usual fixed wiring, plug-in solutions, such as HanB, Han Eco, Han Com, Han E and Han Modular from HARTING’s offerings are good solutions for this application.
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Figure 3: Slip Ring Coupling
In all scenarios, using plug-in connectors provides a convincing case to users in the form of a reduction in costs and time expenditure. Connectors speed up installation and increase the modularity of a wind turbine, reduce investment and operating costs, and provide options for the optimisation and modularisation of the power cabinets. In addition, without a modular design the on-site logistics of onshore plants with an average output of 3.3 MW – including connectors – would quickly reach their limits. As a rule, the cost associated with the use of plug-in connectors is usually amortised within just a few years in the form of cost and time savings.
In addition, HARTING produces LED lighting systems as turnkey system solutions with pluggable device connection, pre-assembled cables, distribution units and, if required, uninterrupted power supply. Lights can be sited in a plant in such a way that their total number remains low and energy costs decrease.
HARTING also offers high-precision current transformers for metering for wind turbines which can be used to connect display devices such as current meters and voltage meters. On request, HARTING can also have its current transformers for metering specially calibrated by a state-approved body in order to further boost the precision of a metering and billing process that employs the devices.