Direct drive synchronous generator wind turbine models for power system studies

The large-scale integration of wind power into modern power systems has set novel challenges for wind turbine modeling and analysis. Accurate modeling of different wind turbine technologies is becoming a necessity as wind turbines replace conventional units in the production side. This paper describes models for two major variable speed wind turbine types namely Electrically Excited Synchronous Generator (EESG) and Permanent Magnet Synchronous Generator (PMSG). Steady state principles of both types are analyzed and mathematical modeling of crucial components is described. The behavior and operation of the system during stochastic wind speed series is simulated using software tools Matlab and PowerFactory. The two configurations are accessed based both on the steady state characteristics and the control system designs. The paper covers a wide range of control methods, which are implemented in both wind turbine schemes. Regarding the PMSG scheme, an advanced damping controller to damp possible oscillations excited in the drive train is presented and its contribution to the safe operation of the wind turbine is explained. In the alternative direct drive scheme (EESG) three different control methods applied in the electrical system are presented.