Robust damping of multiple swing modes employing global stabilizing signals with a TCSC

Summary form only given. This work demonstrates a robust damping control design for multiple swing mode damping in a typical power system model using global stabilizing signals. A multiple-input, single-output (MISO) controller is designed for a thyristor controlled series capacitor (TCSC) to improve the damping of the critical inter-area modes. The stabilizing signals are obtained from remote locations based on observability of the critical modes. A H-infinity damping control design based on the mixed-sensitivity formulation in a linear matrix inequality (LMI) framework is carried out. It is shown that, with local signal, supplementary damping control through three flexible AC transmission systems (FACTS) devices is necessary to provide damping to the three dominant inter-area modes. On the other hand, the use of global signals has been shown to improve the damping of all the critical inter-area modes with a single controller for the TCSC only. The damping performance of the centralized controller was examined in the frequency and the time domain for various operating scenarios. The controller was found to be robust against varying power-flow patterns, load characteristics, tie-line strengths and system nonlinearities, including saturation.