Frequency regulation of an isolated hybrid power system with Battery energy storage system

This paper presents operation and control of a hybrid Photovoltiac Power, Diesel-Engine Generator (DEG) - Battery energy storage system (BESS) connected to an isolated power system. A case study on the impact of BESS operations on the frequency stability of the hybrid system has been carried out. The limits on state of charge (SOC) due to limited storage capacity have also been incorporated. Simulation of a hybrid system model has been carried out in two cases, steady state analysis of hybrid system using step load response with PI controller and other real time performance analysis for a typical day with random variation in load demand. Parameters of controllers are optimized with Genetic Algorithm. Simulation of a hybrid system model is done with the Matlab/Simulink environment. Simulation results indicate that BESS system can contribute to frequency stability in both cases when the load increases and when the load drops. This feature of BESS system will be helpful if it is operated along with a hybrid Wind-PV System.