Dynamic Analysis of Wind Farm Using Induction Generator Wind Turbines

The vast majority of wind turbines that are currently being installed use one of the three main types of electromechanical conversion system. The first type is known as the Danish concept. The second type uses a doubly fed induction generator instead of a squirrel cage induction generator. The third type is called the ‘direct-drive wind turbine’ because it does not need a gearbox. In this paper (asynchronous) squirrel cage induction generator is used to convert the mechanical energy into electricity. Owing to the different operating speeds of the wind turbine rotor and the generator, a gearbox is necessary to match these speeds. Pitch-controlled variable-speed wind turbine types have been built too. The rotor speed is controlled by changing the generator power in such a way that it equals the value derived from the goal function. In this type of conversion system, the control of aerodynamic power is usually performed by pitch control. This paper deals with the dynamic response of wind induction generator connected to the transmission network. Dynamic response of wind geneartor and the network in the case of the two-phase and threephase faults will be discused in this paper. Effects of failure will be considered in the case of connected and disconnected device for additional reactive power compensation, STATCOM. Namely reactive power absorbed by the induction generator is partly compensated by capacitor banks connected at each wind turbine low voltage bus. The rest of reactive power required to maintain voltage close to 1 pu is provided by STATCOM. This paper will show how the dynamic response of the system in case of different types of failure to generator an to the network and what is the role of static reactive power compensator, then how the wind turbine protection system reacts in these cases.