Multi-Stage Fuzzy Load Frequency Control Based on Multi-objective Harmony Search Algorithm in Deregulated Environment

A new Multi-Stage Fuzzy (MSF) controller based on Multi-objective Harmony Search Algorithm (MOHSA) is proposed in this paper to solve the Load Frequency Control (LFC) problem of power systems in deregulated environment. LFC problem are caused by load perturbations, which continuously disturb the normal operation of power system. The objectives of LFC are to mini small size the transient deviations in these variables (area frequency and tie-line power interchange) and to ensure their steady state errors to be zero. In the proposed controller, the signal is tuned online using the knowledge base and fuzzy inference. Also, to reduce the design effort and optimize the fuzzy control system, membership functions are designed automatically by the proposed MOHSA method. Obtained results from the proposed controller are compared with the results of several other LFC controllers. These comparisons demonstrate the superiority and robustness of the proposed strategy

OPTIMAL DESIGN OF FUZZY POWER SYSTEM STABILIZER IN MULTI-MACHINE ENVIRONMENT BY HARMONY SEARCH ALGORITHM

This paper presents an optimal design of Fuzzy Power System Stabilizer (FPSS) using Harmony Search Algorithm (HSA) in multi-machine power system. The PID controller is one of the appropriate techniques to damp low frequency oscillation in nonlinear systems. The proposed controller is based on their rule base and membership function information. In conventional techniques the information is obtained by trial and error which needs too much time. So, finding the optimum value of rule base or membership function is really important. Accordingly, HAS is proposed in this paper to find the optimum value of rule base by considering the power system constrains and factors. This newly developed control strategy mixed the advantage of HSA and Fuzzy controller with simple structure while is easy to implement. Hence, the proposed controller is tested over the New England 10-unit 39-bus standard power system and 9 buses IEEE power system, under various system configurations and loading conditions, to illustrate the performance of the proposed method. The effectiveness of proposed controller is compared with other techniques. Eigenvalue analysis and nonlinear simulation results show the effectiveness of the proposed controller