A suboptimal power-point-tracking-based primary frequency response strategy for DFIGs in hybrid remote area power supply systems

Due to the presence of a power electronic converter, the doubly fed induction generator (DFIG)-based wind generators are isolated from grid frequency variations, which will impose significant burden on conventional generators to regulate frequency in a hybrid remote area power supply (RAPS) system. Thus, participation of wind generators in frequency control is increasingly demanded. In this paper, a primary frequency response strategy is proposed for the DFIG to regulate the RAPS system frequency. A droop control loop without conventionally used high-pass filter is integrated to generate the torque reference for the DFIG to provide primary frequency response, and a supplementary control loop is proposed to enhance the primary frequency response with torque feedback control. Furthermore, the suggested suboptimal power point tracking strategy is capable of reserving wind power to improve the frequency response. The proposed strategy enables DFIG to participate in RAPS system frequency regulation while alleviating high rate of change of power and thus stress on the diesel generators under highly variable load demand. The effectiveness of the proposed strategy is validated through simulations.