Transient support to frequency control from wind turbine with synchronous generator and full converter

The aim of this paper is to describe two regulators for a wind turbine equipped with a synchronous generator and a full converter for the interconnection to the grid. The idea is to extract a temporary amount of power from the wind turbine in order to provide short-term frequency support. The wind turbine model presented is specifically designed to analyse effects of wind generation on the electric grid. The first proposed regulator works to decelerate the rotor and hence transferring part of its kinetic energy to the electric grid: this can be done with variable speed wind turbines because the presence of electronic converters decouples the rotational speed of the turbine rotor from the grid frequency. The second proposed regulator acts on the pitch angle of the blades. Normally wind generators work at maximum efficiency: in this case a reserve of power is obtained working at a degraded point in the aerodynamic characteristic and it can be injected into the grid by pitching the blade. The simulation for testing the behaviour of the two regulators is performed in Matlab-Simulink using the Phasor simulation mode of SimPowerSystems.