An intelligent fuzzy controlled SSSC to enhance power system stability

This paper proposes and experimentally demonstrates two analyses of various novel control strategies for SSSC controllers, including intelligent rule-based controllers (where the power flow oscillation stabilizer action can be adjusted on-line using automatic gain scheduling criteria) and fuzzy logic controllers. Modern control strategies are found to significantly improve the performance of the SSSC. In particular, the proposed fuzzy logic controller uses the steady state relations of the machine rotors angle and electrical power as the input signals and does not require a dynamic model of the system for a satisfactory control design. It is not sensitive to the variation of system structure, parameters and operation points and can be easily implemented in a large scale nonlinear system. In addition, another novel proposal is intelligent error driven integrator for SSSC. The intelligent error driven integrator is based on the concept of the error excursion plane where the stabilizing action is scaled by the magnitude of the power error signal, voltage error signal and the reactance error signal in order to ensure adequate compensation. The proposed rule based design is robust and tolerates system parameter variations as well as modeling inaccuracies, since the control level (gain of the PI controller) is only scaled by the input error signal.