Capacitance for wind turbines
2016/2/26 9:51:54
Capacitors can help wind turbines improve grid reliability and efficiency while reducing maintenance. In the last five years or so, wind turbines have started to incorporate what is called blade-pitch control. This allows wind turbine operators to maximise the angle to the wind (or pitch) for each individual blade, so they get the most spin out of each turbine, and it also allows them to pitch the blades out of the wind if there is an emergency – such as a high-wind event– to keep the blades from spinning too fast.
For reliable and safe operation, turbine manufacturers use either hydraulic or electrical-based pitch control systems. In recent years there has been a trend towards electrical pitch control systems because of environmental and main-tenance concerns. To ensure reliable and safe operation of the electrical pitch control systems, capacitors are used to provide the necessary boost power or back-up power, in the event of a power loss, to orient the rotor blades in a fail-safe position. To do this, manufacturers originally used hydraulics, and then they went to batteries, but they are quickly moving towards ultraca-pacitors because of the short life cycle of batteries. About 75% of electrical pitch systems now use capacitors.
For wind turbines, capacitors can also smooth the output of the wind gen-erator. The smoother the energy output is, the more you can charge for your energy. A capacitor is a short-term uninterruptible power supply for several seconds, not hours or minutes. If there is a slight change in wind speed, the capacitor can provide energy to hold up the output, leading to a smooth transition. If there is an overcharge, the capacitor accepts that energy.
At HUSUM Wind 2015 capacitor specialist FTCAP (Booth 4C02) is presenting a series of solutions for wind turbines. An example is an innovative capacitor module. Users obtain a module that is ready for installation. FTCAP designs and manufactures capacitor modules according to customer specifications.
FTCAP also participates actively in research on new capacitors specially designed for wind energy applications – for example, in the context of the innovation cluster power electronics for renewable energy supply.
FTCAP has expertise in a range of high-performance capacitors for inverters. An example is the high temperature dielectric PEN-HV, which can handle temperatures up to 125°C. On 16 September at 16:10 in the foyer of the Congress Centre, Dirk Hermann, Head of Sales at FTCAP, will give a presen-tation on ‘Elko versus Fiko: Innovations in capacitors’