New stability control strategy for power system under small signal disturbance considering time delay influence

摘要

Power system may not return to its original status and become unstable when subjected to small signal disturbance. Conventional small signal stability (SSS) theory is based on linear control system model without time delay and thus it is not fit for power system stability analysis and stabilization design when relatively larger signal transmission delay exists. In order to overcome the limitations of conventional SSS theory, a new SSS model considering time-varying delay influence is proposed and a kind of state feedback controller is designed to enlarge time delay stability margin of power system and ensure that power system is stable when subjected to small signal disturbance even if the signal is delayed for a certain period. The proposed controller gain can be easily obtained by: (a) parameter adjustment method by using LMI solver; (b) iteration searching method by solving nonlinear minimization problem. Simulation tests demonstrate the influence of time delay on power system small signal stability and verify the correctness of the proposed stabilization control strategy.