Implementation of Battery Energy Storage System for an Island Microgrid with High PV Penetration

This paper presents innovative control strategies that involve a battery energy storage system (BESS) for a microgrid power system on an offshore island with a high penetration of photovoltaic renewable energy. An intelligent energy management system (iEMS) was developed to perform the supervisory control and data acquisition of diesel generators (DGs), distribution feeders, a photovoltaic system and the BESS. An expert system is embedded in the iEMS to support decision-making for fast discharging of power from the BESS to improve the transient stability of the grid under large disturbances, such as the tripping of the DGs or the photovoltaic farm. To maintain the stable operation of diesel generators, the impact of fluctuations in photovoltaic power generation is mitigated by adaptive power charging and discharging of the BESS to smooth of the renewable power output. To support the economic dispatch of the microgrid, a strategy of peak shaving and valley filling of the net system load profile is performed to improve the system load factor using the BESS; the strategy considers hourly forecasting of the system loading and solar power generation. The results of a system simulation and field test demonstrate that the proposed control strategies that involve the BESS significantly improve the power service quality and transient stability of the system in the island microgrid, which has a high penetration of renewable generation.