SMES strategy to minimize frequency fluctuations of wind generator system

Due to random variations of wind speed, output power of wind generator fluctuates randomly, and consequently fluctuations of power system frequency occur. These frequency fluctuations pose serious problems on the system, for example, lamp flicker and inaccuracy in the timing devices. Therefore, minimization of fluctuations of power system frequency is very important from the viewpoint of power system security. This paper proposes an SMES (superconducting magnetic energy storage) strategy for minimization of frequency fluctuations of grid-connected wind generator system. A multi-machine power system consisting of hydroelectric generators, diesel generators and a fixed speed wind generator is considered. The performance of SMES is evaluated in detail considering different load demands and energy capacities of SMES. Simulation results demonstrate that the proposed SMES is a very effective means of minimization of frequency fluctuations of power system including wind generator. Also, the proposed SMES can well smooth the transmission line power. Moreover, it is seen that the SMES with larger energy capacity is better from the viewpoint of fluctuations minimization. However, to reduce the installation cost, the SMES size should be selected such that it is a tradeoff between higher cost and better performance.