Frequency control method based on the dynamic deloading of DFIGs for power systems with high-proportion wind energy

摘要

Limited by the reserve capacity and control speed of synchronous generator (SG), the prediction error of wind power (PEWP) results in severe frequency problems in power systems with high-proportion wind energy. The deloading of doubly-fed induction generators (DFIGs) is an effective way to provide active power support for the grid frequency. However, the existing methods are usually based on a fixed deloading rate, which is difficult to match the uncertainty of PEWP. Accordingly, a new idea of dynamic deloading is proposed considering the influence of safe limit of DFIGs, prediction error of wind power, spinning reserve of SGs, and system operating costs. The positive and negative reserve capacities of DFIG are derived based on coordinating the rotor accelerating control and pitch angle control. The allocation principle of the reserve capacity of DFIGs and SGs for frequency regulation is built. Thus a partitioned scheduling mode of power systems with high-proportion wind power based on the optimal deloading of DFIGs to participate in frequency regulation control is proposed. The simulation shows that the proposed method can simultaneously satisfy the dynamic frequency regulation demand and operating costs of power systems.