Optimal location of terminal voltage nonlinear excitation controller to mitigate small signal stability problem

This paper aims at the selection of optimal location of the terminal voltage nonlinear excitation controller to mitigate small signal stability problem. The controller consists of inverse compensator and proportional controller. One is designed to cancel nonlinear characteristics of the controlled object, the other is used to formulate the closed loop. Based on the simplified model of the generator with terminal voltage nonlinear excitation controller, the linear model of a multi-machine power system is derived. The objective of the optimization is to maximize the sum of damping ratios as much as possible, and the Particle Swarm Optimization (PSO) algorithm is used to investigate this problem in order to optimize the location and parameter of nonlinear controller. To show the validity of the proposed method, simulation results are presented and discussed for IEEE 9-bus system.