Coordinated design of PSS and TCSC based on Fuzzy controller using global signals

This paper presents a modified chaotic gravitational search algorithm (CGSA) as a novel heuristic algorithm for coordinate design of fuzzy logic controller-based thyristor controlled series capacitor (FLC-TCSC) and power system stabilizers (PSSs) in multi-machine power system. The coordinate design of PSS and FLC-TCSC damping controllers is converted to a single optimization problem with the time-domain objective function which is solved by the proposed CGSA algorithm which has strong ability for finding the most optimistic results. By minimizing the employed fitness function in which oscillatory characteristics between areas are included, the interactions among the FLC-TCSC controller and PSS under transient conditions in the multi-machine power system are enhanced. The generator speed and the electrical power are chosen as global input signals. The system performance is assessed through the time multiplied absolute value of the error (ITAE), Eigenvalues and figure of demerit (FD) analysis performance indices. The robustness is tested by considering several operating conditions to establish the superior performance with the proposed controller over the other stabilizers.