Design of an output feedback variable structure thyristor-controlled series compensator for improving power system stability

An output feedback variable structure controller is designed for a thyristor-controlled series compensator (TCSC) in order to improve the damping characteristic of a power system. Physically measurable real power and reactive power signals near TCSC locations are used as the inputs to the variable structure controller. These input signals are employed to construct the switching hyperplane of the proposed variable structure TCSC controller. To demonstrate the effectiveness of the proposed variable structure TCSC controller, time-domain simulations are performed on a power system with a TCSC. It is concluded from the simulation results that system damping can be significantly improved by the proposed variable structure TCSC controller.