Effects of Control Strategy on Sizing of Energy Storage Systems for PV-Wind Power Plants

Abstract

Different control strategies can be used with energy storage systems (ESS) to mitigate power fluctuations of photovoltaic (PV) and wind power plants. Control strategies can significantly affect the required size of the ESS. In this paper, ramp rate (RR), moving average (MA) and low-pass filter (LPF) ESS control strategies are compared for PV, wind, and PV–wind power plants. It was found that the required relative charging and discharging powers of the ESSs were quite similar between the different strategies. For the RR strategy, the required relative ESS energy capacity was found to be the highest and the utilization rate was found to be the lowest among the 3 strategies. The energy level in the ESS was found to behave differently with the RR strategy than with the MA and the LPF strategies. It was also found that with the RR strategy the behavior of the ESS energy level differs between the PV and the wind power plants. With PV power, the energy level of the ESS tends to slowly decline below an initial level during a day, but for wind power, it tends to elevate moderately fast and clearly farther away from the initial level.