Optimal Design of Fopid Controller for Lfc in an Interconnected Multi-source Power System

This paper addresses optimal design and performance analysis of the Social Spider Optimization (SSO) algorithm based Fractional Order Proportional Integral Derivative (FOPID) controller for load frequency control (LFC) in an interconnected multi-source power system. Since this controller has more adjusted parameters than classical proportional-integral-derivative (PID) controller, thus it provides better dynamics performance. Hereby, optimal tuning of controller parameters is converted to an optimization problem with time domain objective function which SSO algorithm solves it. The proposed objective function consists of frequency deviation in each area and tie-line power deviation which using appropriate weighting coefficients are associated with each other. The proposed controller has been applied on a two-area test system includes six generating units which one of them has (High Voltage Direct Current (HVDC) link. The simulation results show good performance in comparison with other well-known controller. Furthermore, to illustrate the robustness and stability of the proposed controller, the power system has been studied under nonlinearities conditions such as Generation Rate Constraint (GRC) and Governor Dead Band (GDB) and uncertainties in system parameters with changing between -50% to +50% of nominal values. The results show the high ability of the optimized FOPID controller based on SSO algorithm to overcome the LFC problem in multi-source two area interconnected power system.