Modeling and Operation Strategy Research on Flexible Wind Farm Grid-connection Auxiliary System

Abstract

Present energy storage system assisting flexible wind farm grid-connection in minute timescale is generally composed of battery. Restrained by capacity, this kind of energy storage system topology is unable to continuously operate when wind power fluctuation is persistently over-limit. In order to solve this problem, this paper introduced a hybrid energy storage system (HESS) topology composed of battery andhydrogen conversion system (HCS). In order to achieve flexible wind farm grid-connection with the least energy loss, an HESS control strategywas proposed to make full use of advantages of HCS capacity and battery energy conversion efficiency. The optimization goal was to minimize power fluctuation, battery life consumption and energy loss. Energy conversion characteristicswere also analyzed. Simulation results showed that, compared with other strategies only using battery, the operation strategy using HESS under the same economy cost could combine advantages of battery efficiency and HCS power supply continuity and achieve balance of induced energy loss and power fluctuation.