Alleviation of Extremely Power and Voltage Variations Caused by Wind Power and Load Demand Using SMES

Abstract

Due to the high variations in wind speed and the continuing changes in load power demand (LPD), power and voltage at the point of common coupling (PCC) fluctuate according to the variations of injected wind power generation (WPG) and LPD simultaneously. Superconducting magnetic energy storage (SMES) plays a significant role in alleviating the power/voltage at PCC. This paper shows the impact of SMES in enhancing the performance of interconnected WPG system during high wind gust variations and the changes in LPD. WPG includes squirrel-cage induction generator (SCIG) type with a shunt-connected capacitor for improving the power factor. WPG, SMES and the load are located at PCC. Fuzzy logic control (FLC) is used with the DC-DC chopper to control the power exchange between AC system and SMES. FLC is designed where SMES can absorb/inject real power from/to the grid. On the other hand, reactive power is controlled to adjust the variation of PCC voltage. Two inputs are applied to the FLC; the summation of wind power variation and change of LPD as the first input and the variation of SMES current is the second one to control active power transferred between SMES and AC system. The suggested control approach of SMES is a fast response, as it successfully controlled the PCC voltage, line active and reactive powers during wind gusts and the variations of the load side.