Research on the analysis and evaluation method of starting capability for induction motors in a black-start isolated microgrid with energy storage systems

Abstract In the early phase of a power system’s black start, the battery energy storage system (BESS) emerges as an effective auxiliary power source. However, a significant and challenging issue during this phase is the initiation of large-capacity induction motor (IM) auxiliary devices. This paper introduces an analytical and evaluative approach for the starting capacity of IM loads with BESSs in parallel, along with an optimized BESS capacity configuration plan. Initially, the mathematical models for both BESS and IM are dissected, establishing a dynamic equivalent circuit for the paralleled BESSs initiating IM loads under a master-slave control strategy. Subsequently, the voltage/current constraints on the energy storage side are taken into account to define the stable operation range of the black-start isolated power grid. Following this, an evaluation method and metric for the starting capability of paralleled BESSs with IM loads are introduced. An optimization plan for the capacity configuration and distribution of grid-forming (GFM) and grid-following (GFL) controlled BESSs is devised based on these metrics. The validity of the proposed metrics and configuration scheme is ultimately confirmed through MATLAB/SIMULINK simulation.