From the Enercon brochure:
ENERCON storm control
ENERCON wind turbines run with a special storm control feature.
Storm control enables reduced wind turbine operation in the event of
extremely high wind speeds, and prevents typical shutdowns which
cause considerable yield losses.
Power curve with ENERCON storm control
The power curve diagram showing operation with ENERCON storm control (illustration 2) demonstrates clearly that the wind turbine does not shut down automatically when a certain wind speed Vstorm is exceeded, but merely reduces power output by slowing down the rotational speed. This is achieved by slightly pitching the rotor blades 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. This prevents yield-reducing shutdown and start-up procedures.
Data for a 7.5MW wind turbine Enercon E126
As can be seen from the plot and data useful power is available from 4 to 25 m/s
Enercon Control systems being electronic can synchronise to grid quickly and can even help the grid ride out a system fault.
NO Rare earths are required for the generator
NO gears are required for the main shaft of the generator
Staying connected when grid problems occur
Most transmission networks and ever more distribution grids require wind energy converters to remain connected to the grid in the event of grid short circuits. Like conventional power plants, wind turbines are not allowed to suddenly disconnect from the grid during voltage dips or overvoltage caused by grid problems. ENERCON wind turbines with the optional ENERCON UVRT feature have this capacity. No matter what type of short circuit occurs, ENERCON wind turbines can ‘ride through’ faults for several seconds, even if they were operating at rated power before the fault. This is also possible if the wind turbine voltage completely breaks down as a result of a power system failure. These outstanding power plant properties have been certified by independent institutes during actual grid fault testing. Flexible setting options offer maximum performance according to the respective grid operator’s specifications or to the project’s framework conditions.
Depending on the selected parameters, the wind turbine can feed in either mainly active or reactive power to maintain grid voltage. If necessary, voltage-dependent reactive current can even be supplied to the grid; this current can be maximum rated current as stipulated by the latest German grid code. If desired or required, fault ride-through is also possible without power feed-in. The ENERCON wind turbine remains in operation during the fault. After the grid problem has been resolved and grid voltage has been restored, the wind turbine can immediately resume power feed-in. Thus the ENERCON Undervoltage Ride-Through feature facilitates adaptable settings in order to meet grid standards (e. g. of the German
Association of Energy and Water Industries) and to maximise the amount of installable wind farm power.
ENERCON WECs produce clean energy without neodymium