Delay-Dependent Stability Control for Power System With Multiple Time-Delays

Time-delay exists widely in electric power systems, and is found to have significant effect on the performance of operation and control under certain conditions. It is shown that even a very small delay may destabilize the power system. Therefore, time-delay is of important concern and should be properly handled, especially in the wide-area measurement and control environment. However, only few results about the controller design for power system considering multiple time-delays are reported. In this paper, a multiple time-delayed power system model is constructed with power system stabilizer (PSS) considering time-delays. By using Lyapunov stability theory and linear matrix inequality (LMI) method, two H-infinity control schemes are developed for time-varying multiple delayed systems. The proposed controllers guarantee the closed-loop system asymptotic stable with H-infinity performance. A two-area four-machine power system and the New England 10-machine 39-bus system are employed to demonstrate the effectiveness of proposed methods. The simulation results verify that the designed controllers can improve the control performance significantly.