Reconfigurable Fault-tolerant PSS and FACTS Controllers

This article presents a design technique for reconfigurable fault-tolerant controllers acting on a flexible AC transmission system power system. A classical power system stabilizer of the generator excitation system and a controller of the thyristor-controlled series capacitor are considered. Sound operation of both controllers yields the required dynamic performance of the system. However, a faulty condition signifies a degraded control signal of one controller at a time. The proposed scheme suggests that the parameters of one controller switch to some predetermined values if the other controller is faulty with any degradation percentage. Maintaining a specific settling time of the dynamic response is assured against continual degradation of either controller as the design is carried out through the Kharitonov theorem and particle swarm optimization. The proposed design represents an indirect adaptive power system stabilizer. Simulation results denote distinct effectiveness of the proposed design in maintaining the desired system performance under sound and different faulty conditions.