Solution to short-term frequency response of wind farms by using energy storage systems

The increasing high penetration of wind power is bringing a serious challenge to the frequency regulation of power system, for wind turbine generators are unable to naturally contribute to system frequency response. To address this problem, this study proposes a control strategy to compensate the lack of short-term frequency response ability of wind farms (WFs) by the energy storage system (ESS). First, the rated power and capacity of the ESS, which is installed at the point of common coupling of the WF to make it have similar short-term frequency response ability to that of synchronous generators, are determined. The theoretical minimum rated power of the ESS should be about 5% rated power of the WF, only if the active power output of the ESS is controlled as its rated power during the whole inertial response process. Then, a fuzzy logic controller is designed for the ESS so that the required rated power of the ESS could reach its theoretical minimum value as closer as possible. Simulation results of a simplified practical power system show that WFs with the proposed strategy could response to the frequency change rapidly and support short-term frequency control effectively under various disturbances.