A dynamic model of battery energy storage system based on the external characteristic equivalent

Abstract

With the increasing application of battery energy storage in the power grid, there will be inevitably a large number of battery energy storage systems (BESS) in the future distribution network. It is very important to study the equivalent model of BESS which is suitable for comprehensive load modelling. In this paper, the battery group is established based on a type of general battery model, and then, a simulation platform of BESS based on MATLAB/Simulink is constructed, using a double closed loop control strategy with constant power as control object. Through the simulation analysis of grid-connected characteristics of BESS, a semi-mechanism dynamic model of BESS based on the external characteristic equivalent is proposed. This model represents the variation trend of the electrical variables of BESS during transient state, and considers the inertia characteristics of the BESS relative to power grid. By comparing the simulation results under different disturbance intensity, the proposed model can describe the transient characteristics of BESS, and can meet the performance requirements of the load modelling for the distribution network side.