Application of SMES for voltage control of power systems with high wind power penetration

This paper studies the impact of superconducting magnetic energy storage (SMES) for voltage control of electrical power systems associated with variable power from wind farms. Wind energy generation system (WEGS) used in this paper is of fixed-speed wind turbine type based on squirrel cage induction generator (SCIG) linked with capacitor bank for improving the power factor. SMES system contains a converter transformer, power conditioning unit, two quadrant DC-DC chopper, large inductance coil, and cryostat/vacuum vessel to keep the coil in the superconducting state. WEGS and SMES system are located at the same bus of the grid for achieving better improvement. Fuzzy logic controller (FLC) is applied to the DC-DC chopper to manage the power interchange between the grid and SMES. The FLC is planned so that the SMES can inject/absorb active power to/from the AC distribution system. On the other side, reactive power can be controlled to transfer between the distribution system and SMES, according to the voltage difference between the average SMES coil voltage and the DC-link capacitor voltage. To enhance the control performance, FLC was implemented by two inputs variables; the change in SMES current and variation in wind speed. Comprehensive simulation model is carried out using MATLAB/Simulink program and Sim-power system toolbox.