On battery storage system for load pickup in power system restoration

During power system restoration, it is critical to maintain system frequency stable to avoid any further outage or cascading events. Load pickup is one of the most important tasks to keep generation-load balance for a stable system frequency. In current industry practice, small loads are suggested to be picked up incrementally to avoid any instable frequency dip. However, slow load pickup may prolong the system restoration process. As the fast response energy resources, battery storage system (BSS) can expedite the load pickup by compensating the imbalance between generation and load. In this paper, a battery dispatching strategy is developed for faster and more reliable load pickup in system restoration. The frequency response rates (FRRs) of generators are utilized to pick up loads in each step while maintaining frequency stability. Batteries are used to maximize the load pickup. The State of Charge (SOC) of batteries is monitored and kept within specified limits. Simulation results demonstrate that batteries can support to increase total served energy and reduce system restoration time. The battery charging/discharging time and sequence depends on the generation and load profile, and the size of BSS. This paper further discusses the impact of FRR of BSS on frequency dynamics in load pickup.