Robust coordination damping control of multi-model system with FACTS devices via sequential approach

In this paper, multiple flexible AC transmission systems (FACTS) supplementary damping controllers are designed for the enhancement of system small-signal stability under different system operating points. A static var compensator (SVC) and a thyristor-controlled series compensator (TCSC) damping controller are designed sequentially with minimized decoupling effort. This approach is carried out with a bilinear matrix inequality (BMI)-based multi-objective multi-model method. In each step, a single input and single output feedback controller is designed to increase system damping ratios of several inter-area oscillatory modes under nominal and off-nominal operating points. Regional pole placement and control effort optimization are set as the control objectives. Controller designs are implemented on a five-area 68-bus system and the test system is verified by non-linear simulations in real-time digital simulator (RTDS).