Load frequency control of three unit interconnected multimachine power system with PI and fuzzy controllers

The load on the power system is always varying with respect to time which results in the variation of frequency, thus leading to load frequency control problem (LFC). The variation in the frequency is highly undesirable and maximum acceptable variation in the frequency is ± 0.5Hz. In this paper load frequency control is done by PI controller, which is a conventional controller. This type of controller is slow and does not allow the controller designer to take into account possible changes in operating conditions and non-linearity's in the generator unit. In order to overcome these drawbacks a new fuzzy load frequency controller is presented to quench the deviations in the frequency and the tie line power due to different load disturbances. The effectiveness of the proposed controller is confirmed using MATLAB/SIMULINK software. The results shows that fuzzy controller provides fast response, very less undershoot and negligible peak overshoots with having small state transfer time to reach the final steady state. In this paper for single area, two area and three area the effectiveness of fuzzy controller is verified.