Dynamic Performance Improving Strategy for Primary Frequency Regulation With Energy Storages in High Penetration of RESs Power System

The increasing penetration of renewable energy sources brings about severer frequency fluctuation problem, and the recovery speed and probability of frequency crossing dead band are very important dynamics for frequency regulation performance. In this paper, a comprehensive frequency regulation strategy of energy storage is proposed to improve the frequency dynamic performance. Firstly, the system frequency response model is introduced, and the frequency variation characteristics faced with high penetration of renewable energy sources are analyzed, based on which the principles of proposed strategy are elaborated. Then, an inverse inertia is designed to improve the frequency recovery speed after nadir, of which the stability margin is carefully analyzed to determine the inertia coefficient value. Further, a revised dead band of energy storage participating in frequency regulation is proposed to improve the frequency dynamic performance, of which the nonlinear characteristics is analyzed by describing function method to guarantee the system stability. The performance of the proposed control strategy is validated by the simulation cases with different operating scenarios. The results show that the proposed strategy can smooth the frequency fluctuation, reduce the probability of frequency deviation crossing the threshold, and speed up the frequency recovery speed without increasing the energy storage capacity demand.