Evaluation of battery energy storage capacity required for battery-assisted load frequency control contributing frequency regulation in power system with wind power penetration

With the rapid growth of Intermittent Renewable Energy Sources (IRES) such as photovoltaic and wind power generation, performance improvement of frequency control is getting more important. In order to solve the problem, the authors proposed Battery-Assisted Load Frequency Control (BALFC) as a novel battery utilization method for LFC performance enhancement in previous works. Under large penetration of IRES, the existing generation plant such as thermal power plant cannot follow the LFC signal because of ramp rate limit. The BALFC drives the battery to compensate the excess components of the LFC signal over the limitation. In this paper, at first, the SOC control is combined with the BALFC to avoid full charge or out of charge. And next, required MW and MWh capacity of the battery system is evaluated to show the availability of the proposal. The computation of required battery capacity is conducted on power system model in which large wind power penetration is assumed. As a result of comparison study with a conventional battery utilization method, Filter-Based LFC, it is clarified that the required MW and MWh capacity of the BALFC is smaller than that of the Filter-Based LFC regardless of the amount of wind power generations. The SOC control reduces required MWh capacity significantly while the required MW capacity is slightly increased. An observation of time-domain simulation results reveals that the effectiveness of the BALFC is brought by its simple configuration which does not include any additional filters causing phase delay of control signals.