Performance and health test procedure for grid energy storage systems

A test procedure to evaluate the performance and health of field installations of grid-connected battery energy storage systems (BESS) is described. Performance and health metrics captured in the procedures are: round-trip efficiency, standby losses, response time/accuracy, and useable energy/state of charge at different discharge/charge rates over the system's lifetime. The procedures are divided into reference performance tests, which require the system to be put in a test mode and are to be conducted in intervals, and real-time monitoring tests, which collect data during normal operation without interruption. The procedures can be applied on a wide array of BESS with little modification and can thus support BESS operators in the management of BESS field installations with minimal interruption and expenditure. Simulated results based on a detailed system simulation of a prototype system are provided as guideline.