Optimal Dispatching Method of High-proportion Wind Power Systems Considering Wind Power Reserve for Frequency Adjustment

Limited by the reserve capacity and speed of the synchronous generators, the frequency reliability of wind power systems with high-proportion wind energy caused by wind speed fluctuations is becoming increasingly severe. Wind power reserve of variable speed wind turbines (VSWTs) is effective to solve the random impacts of wind power. The rate of power reserve of VSWT is the key to the safety and economy of power grids. However, it is difficult to determine the suitable value at the system level due to the influences of reserve capacity, the demand, and the safety constraints of wind speed and VSWTs, which restrains the effects of wind power reserve and even causes a series of safety problems. To this end, an idea of power system frequency adjustment based on dynamic VSWT power reserve is proposed. By fully considering the effects of wind power prediction errors (WPPEs), the VSWT constraints, the reserve capacity of synchronous generators, and the system economy, a dispatching method with wind power reserve for frequency adjustment is proposed in this paper. The effects of the WPPE on frequency is studied. The maximum rate of power reserve, and the maximum positive and negative reserve capacity of the VSWT are derived. A new grid scheduling mode based on dynamic wind power reserve is proposed. Based on the chance-constrained programming, an optimal model considering wind power reserve for frequency adjustment is established. Finally, the validity of the proposed method is verified by simulation studies.