Design of Robust Controller for LFC of Interconnected Power System Considering Communication Delays

Abstract

The usage of open communication infrastructure for transmitting the control signals in the Load Frequency Control (LFC) scheme of power system introduces time delays. These time delays may degrade the dynamic performance of the power system. This paper proposes a robust method to design a controller for multi-area LFC schemes considering communication delays. In existing literature, the controller values of LFC are designed using time domain approach which is less accurate than the proposed method. In proposed method, t he controller values are determined b y moving the rightmost eigenvalues of the system to the left half plane in a quasi-continuous way for a preset upper bound of time delay. Then the robustness of the proposed controller is assessed by estimating the maximum tolerable value of time delay for maintaining system stability. Simulation studies are carried out for multi-area LFC scheme equipped with the proposed controller using Matlab/simulink. From the results, it has been concluded that the proposed controller guarantees the tolerance for all time delays smaller than the preset upper bound and provides a bigger delay margin than the existing controllers.