In a unified power system the Load Frequency Control (LFC) is taken for review looking at all aspects with various optimization techniques for optimizing the parameters of PI, PID and Fuzzy controllers. The power system with multi area consists of conventional, renewable and combination of both with some energy devices like SMES, battery sources is analyzed specifically in this manuscript. The controllers are designed for a deregulated environment of a power system for LFC. The Model Predictive Control (MPC) and some other control techniques are used to control LFC under various disturbances like GRC and dead band control. For the readers ease of understanding the time response comparison graph of the controller for single and multiple areas of power system is depicted. © 2018 University of Kragujevac, Faculty of Science.