Determining the Power and Energy Capacities of a Battery Energy Storage System to Accommodate High Photovoltaic Penetration on a Distribution Feeder

The integration of distributed energy generation systems has begun to impact the operation of distribution feeders within the balancing areas of numerous electrical utilities. Battery energy storage systems may be used to facilitate greater integration of renewable energy generation. This paper describes a method for determining the power and energy capacities a battery energy storage system would need in order to accommodate a particular photovoltaic penetration level within a distribution feeder, or conversely, the amount of photovoltaic that could be installed on a feeder with a minimal investment in power and energy battery energy storage system (BESS) capacities. This method determines the BESS capacities required to compensate both intra-hour and inter-hour load and photovoltaic fluctuations to achieve a flat feeder power profile. By managing the feeder power, the voltage drop along the length of feeder may be managed, thereby mitigating the voltage fluctuation induced by the stochastic nature of both renewables generation and load. Doing so facilitates system benefits, such as conservation voltage reduction, fewer operations of load tap changers, and voltage regulators, and allows for deferment of capital expenditures.