Analysis on DC Side Protection Strategy for Grounded Power Battery Energy Storage System

With the increasing proportion of photovoltaic, wind power and other new energy generation in the grid and the rapid growth of electric vehicles, the uncertain of load in the power grid is increasing. In order to stabilize the load fluctuation and improve the ability of the frequency modulation and peak load regulation of the system, the power storage battery has been widely used in the power system. In this paper, the grounding type power battery energy storage system (PBESS) connected to the power system is taken as the research object. In order to improve its DC side protection performance and ensure the safety of the system. The fault conditions of pole to ground short circuit and the pole to pole short circuit in the DC side are studied. The voltage and current characteristics of the fault are analyzed, and the situation of the pole to ground fault in different positions of the DC side is simulated on PSCAD/EMTDC platform. According to the simulation results, the fault protection strategy of the DC side in the grounded PBESS is proposed. It can ensure that there is a main protection and a backup protection in case of any fault on the DC side, which improves the protection performance and better ensures the safe and stable operation of the system.