Combined deload and kinetic energy control of variable speed wind turbines for frequency support

In this paper, frequency control of variable speed WTs is investigated. Two energy sources de-load energy and kinetic energy of WTs which provide the extra power for frequency support is discussed, the power margin of the two sources are compared, a combined de-load and kinetic energy control of the variable speed wind turbine for system frequency support is proposed, the control strategy takes advantages of each energy source, it uses the kinetic energy to reduce the rate of change of frequency while the de-load energy is aim to provide primary frequency support. The control strategy can fully release the available kinetic energy and de-load energy which will provide an improved frequency support for the power system. Matlab/Simulink simulations based on a simple power system demonstrated the frequency support effect of the proposed strategy.