Application of superconducting magnetic energy storage (SMES) for voltage sag/swell supression in distribution system with wind power penetration

This paper presents the impacts superconducting magnetic energy storage (SMES) in suppressing the voltage sag/swell in distribution systems with wind power penetration. Wind turbine used in this paper is of squirrel cage induction generator (SCIG) with shunt connected capacitor bank to improve the power factor. SMES system consists of step down transformer, power conditioning system, DC-DC chopper, and large inductance superconducting coil. Wind energy generation system (WEGS) and SMES system connected to the grid at the same bus to achieve high performance. Fuzzy logic controller (FLC) used for DC-DC chopper to control in power transfer between the grid and SMES coil. The FLC is designed so that the SMES can absorb/deliver active power from/to the distribution system. On the other hand, reactive power can be delivered/absorbed to/from the distribution system according to the voltage difference between the SMES voltage and DC link voltage. Two inputs were applied to the FLC; bus voltage and SMES current variations. This technique of two inputs was proved to enhance the control performance. Detailed simulation is carried out using Matlab/Simulink and Simpowersystem package.