New algorithms to size and protect battery energy storage plant in smart microgrid considering intermittency in load and generation

Interconnection of large scaled photovoltaic distributed generators into utility networks can adversely influence the operation of next generation smart power systems. Quickly altering output power of this type is random and hence one remedy is to suppress it by short-term to mid-term electrical storage systems. Battery energy storage system (BESS) is one example brought to this end. To compensate for power fluctuations resulted by solar plant together with load, BESS have to be sized accurately. In this paper, a guideline algorithm is proposed which helps to precisely size the BESS. Technical issue related to BESS physical properties are also considered in this method. To protect BESS against over charge/discharge, a current control algorithm is designed as well which adjusts for battery storage plant dispatching reference to ensure that magnitude of battery current is within the operational boundary. A smart microgrid (MG) consisting of diesel, battery storage, and solar plants is implemented in PSCAD/EMTDC to test and validate aforementioned algorithms. The results confirm the efficacy of both algorithms.