Today, in power systems the Load Frequency Control (LFC) problem plays a vital role in an interconnected power system, wherein it maintains the system frequency and tie line flow at their scheduled values during normal period. It is due to frequency of power system, which changes over time with respect to continuous load variation. The present chapter proposes a new methodology to study the Load Frequency Control (LFC) problem of a three area inter-connected system using R Fuzzy system (FS) approach. Moreover, this technique is applied to control the systems which include three areas considering a non-linearity Generation Rate constraint (GRC) having two steam turbines and one hydro-turbine tied together. The main advantage of this controller is its high insensitivity to large load changes and plant parameter variations even in the presence of non-linearity. Furthermore, it is tested on a three-area power system to illustrate its robust performance. The results obtained by using Rule Based Fuzzy PID controller explicitly show that the performance of this proposed controller is superior to conventional controller in terms of several parameters like overshoot, settling time and robustness.

Keywords: Load Frequency Control, Reliability, Fuzzy Controller, Power System