Design of fuzzy+PI controller in application of TCSC and PSS for power system stability improvement

This paper introduces a proportional integral (PI) controller according to Fuzzy-Sugeno logic (FPI) for a thyristor controlled series capacitor (TCSC) in order to improve the stability and to damp the low frequency oscillations. This controller is used with a lead-lag controller for a power system stabilizer (PSS) in a single-machine infinite-bus system. Also, an independent fuzzy controller for PSS is designed to demonstrate the capability of FPI controller. Three compositions of the controllers are implemented to control TCSC and PSS at the same time. Simulation results show that the designed fuzzy+PI (FPI) controller is robust against different loads and faults.