ENERCON wind turbines are equipped with a special storm control system, which enables reduced turbine operation in the event of extremely high wind speeds. This prevents the otherwise frequent shutdowns and the resulting yield losses.

Power curve of a wind turbine without ENERCON storm control

The diagram of a power curve of a wind turbine without ENERCON storm control shows that the wind turbine stops at a defined shutdown speed V3: the reason being that a specified maximum wind speed has been exceeded. In the case of a wind turbine without storm control this, for example, occurs at a wind speed of 25 m/s with the 20 second mean. The wind turbine only starts up again when the average wind speed drops below the shutdown speed or possibly even lower restart speed (V4 in the diagram; so-called strong wind hysteresis). In gusty wind condition, this may take a while, which means that considerable yield losses are incurred.

Power curve of a wind turbine with ENERCON storm control

ENERCON wind turbines run on a different principle at high wind speeds. They are equipped with special storm control software which prevents sudden shutdowns. The power curve diagram with ENERCON storm control demonstrates clearly that the wind turbine does not shut down automatically when a certain wind speed VStorm is exceeded, but merely reduces the power output by lowering the rotational speed. This is achieved by turning the rotor blades slightly out of the wind. Once the wind speed drops, the blades turn back into the wind, and the turbine immediately resumes operation at full power. Yield-reducing shutdown and start-up procedures are thus avoided.

Example: Yield loss of an E-70 wind turbine due to two days of gusty wind per year: 2 days x 2,300 kW = 110,400 kWh 2 - 4 % of yearly income