Hybrid operation strategy of wind energy storage system for power grid frequency regulation

Abstract

This study presents a novel hybrid operation strategy for a wind energy conversion system (WECS) with a battery energy storage system (BESS). The proposed strategy is applied to support frequency regulation using coordinated control of WECS and BESS operations in power system. The coordinated control of the WECS consists of active power control and frequency support control based on permanent magnet synchronous generators for variable wind speed conditions. Active power control is achieved using maximum power point tracking and deloaded operation to ensure a certain power margin. In addition to this comprehensive control of the active power, frequency support control based on kinetic energy discharge control is developed to regulate the short-term frequency response and to ensure reliable operation of the power system. Concurrently, the output power command of the BESS is determined according to the state of charge and frequency deviations. The effectiveness of the hybrid operation strategy is verified by a numerical simulation in power system computer aided design/electro-magnetic transient direct current (PSCAD/EMTDC), and the results show that the proposed approach can improve the frequency regulation capability of the power system.