Inter-area damping control of STATCOM using wide-area measurements

This paper proposed an approach to combining the recently developed FACTS and WAMS technologies to damp inter-area low-frequency oscillations and enhance transfer capability of interconnected power systems. The approach includes three steps: Firstly we use PRBS probing technique and N4SID to obtain a reduced-order model of the studied system. Then wide-area measurements are employed as feedback signals and an optimal damping control loop is designed via LQR approach for the FACTS controller in a multi-machine environment. Finally with communication delays of WAMS considered, a least square prediction algorithm is developed to derive instant feedback quantities, and thus make the proposed control practicable in real systems. To verify the effectiveness of the proposed approach, case study is fulfilled using a two-area four-machine power system with STATCOM, one of the most promising FACTS controllers, connected to the inter-area transmission. Extensive digital simulation results demonstrate its validity in damping inter-area power oscillation and enhancing transfer capability along long-distance tie lines.