Assessment and Choice of Input Signals for Multiple HVDC and FACTS Wide-Area Damping Controllers

This paper proposes a hybrid method to assess and select suitable control inputs for multiple HVDC and FACTS supplementary wide-area damping controllers (WADCs) of large-scale interconnected power system. This method can not only reduce the interaction among different WADCs, but also get good performance of damping multiple inter-area oscillations. The residue analysis method based on observability/controllability index is used to preselect the input signal candidates for each WADC. Then, the relative gain array (RGA) analysis, including the steady-state values and the dynamic behavior, is carried out to evaluate and determine the suitable input signals for multiple WADCs. Since the undesired interaction among multiple WADCs is reduced significantly by the proposed method, we can design each WADC independently without considering the coordination of controllers, which can reduce the design difficulty of multiple WADCs. A detailed case study validates the proposed method, and indicates that the multiple WADCs adopting the selected wide-area signals can effectively damp multiple inter-area oscillations at different operating scenarios (e.g., line fault, line outage, and load shedding).