UPFC controller design for power system stabilization with improved genetic algorithm

This paper presents the genetic optimization of the parameters of a fuzzy PI controller for UPFC (unified power flow controller) using an improved genetic algorithm to enhance the transient stability performance of power systems. The function based Takagi-Sugeno-Kang (TSK) fuzzy controller uses minimum number of rules (two rules) and generates the proportional action, which by one-to-two inference mapping gives a variable gain PI controller. This single input function based scheme dispenses the gain dependency of the proportional or integral gains and generates independent control actions. Computer simulation results on a 2-area 4-machine 12-bus power system with an UPFC installed between buses s and r confirm the efficacy of the new approach in damping the local-mode and inter-area mode of oscillations.