A Novel Control Strategy of DFIG Wind Turbines in Complex Power Systems for Enhancement of Primary Frequency Response and LFOD

In this paper, we propose a novel control strategy for doubly fed wind turbine generators (DFWTG) in complex power systems to improve the primary frequency response and enhance low-frequency oscillation (LFO) damping of power systems. The main innovation in the new control scheme dwells in the novel control schemes for rotor side controller (RSC) of DFWTG. Weighted frequency deviations of local synchronous generator (SG) bus bars are utilized as input signals to a dedicated power system stabilizer, specifically designed for the RSC of DFWTG, with parameters optimized by particle swarm optimization. The newly devised RSC with conventional DFWTG control structure is capable of ameliorating primary frequency response of the power system. To eliminate the area control error, a secondary control scheme is incorporated, which makes use of the spinning reserve of selected SGs through automatic generation control. Tie-line power deviations are employed as control signals in both primary and secondary control schemes, on the purpose of further enhancing the primary and secondary frequency regulations and also maintaining the obligation of power transmissions among adjoining areas. Simulation results demonstrate the superiority of the proposed DFWTG control methods in enhancing primary frequency response and also suppressing LFOs of the power system over the conventional strategy.