Dynamic behavior of Energy Storage System under disturbed grid operating conditions

This paper assesses the dynamic behaviour of an Energy Storage System (ESS) under disturbed grid operating conditions. The ESS is designed, as well as the AC and DC current and voltage controllers, and a Supervisor is developed, that defines the system operation states, and the boundary conditions between them, establishing the references for the currents and voltages to control. Simulation results are obtained and analysed for several test conditions as normal grid operation, island mode and the transitions between operating states. Also, specific grid disturbances, as voltage sags, are simulated. From the obtained results, it can be concluded that the ESS is able to operate connected to the grid and in island mode, and to change between these two modes with minimum disturbances in the load. In island operation, the proposed system is capable of generating a three phase system (Grid Forming), bounded by the limits defined in standard EN 50160.