Generator & Inverter
The WTG is equipped with a doubly-fed induction generator (DFIG) with a converter in the rotor circuit of the generator.
During operation, the stator side of the generator is permanently connected to the grid. The rotor windings are connected to the grid via slip rings and a converter that controls both the rotor and the grid current. Thus, rotor frequency can freely differ from the grid frequency. By controlling the rotor current with the converter it is possible to adjust the active and reactive power fed to the grid from the stator and rotor. An air cooling system keeps the generator at an optimal operating temperature.
The generator is equipped with anti-condensation heaters which are activated when the generator is not in operation (generator switched off or rather is disconnected from the grid) and vice versa. This is done to keep the air temperature inside the generator (not in operation) slightly higher than the surrounding ambient temperature to prevent condensation of moisture inside generator on active parts.