Performance Analysis of Controllers For AGC And AVR in Two Area System

Abstract

Keywords: AGC, AVR, PID, IMC, FLC, FLC-IMC, MATLAB INTRODUCTIONAutomatic generation control is very important issue in power system operation and control for supplying sufficient and both good quality and reliable electric power. The purpose of AGC control is to reduce steady state frequency error of the system to zero [1]. The generator excitation system maintains generator voltage and hence, controls the reactive power flow in power system. The role of AVR is to maintain the terminal voltage magnitude of synchronous generator at a specified level [2]. By PI control approach zero steady state error in frequency of the system is achieved but it exhibits relatively poor dynamic performance which results in maximum overshoot and large settling time. Fuzzy logic is effectively used to change the integral gain of AGC settings automatically to restore nominal system frequency for various wide range load changes in papers [4][5][6]. The terminal voltage magnitude changes due to change in reactive power demand. The potential transformer (PT) senses the voltage magnitude on one phase and it is compared with DC set point signal. The amplifier error controls the exciter field and hence, the main field of the generator for getting a desired value of voltage [7]. This paper presents a development of voltage control of AVR or excitation system by using Fuzzy-IMC controller to overcome nonlinearities and uncertainties in the systems. Fuzzy-IMC is used to make the system internally stable and it gives better result than other implemented controllers [8]. Development of AGC for frequency stabilization using Fuzzy logic controller is also presented. FLC is an intelligent controller which uses IF and THEN rule to obtain optimized result. However FLC makes the system little sluggish [3].