The Study Of Interaction And Coordination Between PSS And TCSC In Damping Osciliations

Power system oscillations of both local mode and inter area mode can be successfully suppressed if auxiliary damping controllers such as power system stabilizer(PSS) and thyristor controlled series compensators(TCSC) are well tuned. When PSS and TCSC are both installed in power system, it is possible they may interact negatively. System mathematic models that contain PSS and TCSC are established and the damping characteristic is studied in detail .The negative interaction was validated through simulation in RTDS. Simulating also indicate that the damping can be improved through coordinating the parameters of the controllers. This thesis employes the Modified Particle Swarm Optimization(MPSO) that was an improved Particle Swarm Optimization(PSO) to coordinate the design of PSS and TCSC controllers. By considering multiple representative operating conditions in constructing the objective function, robustness of the damping controllers is guaranteed. An example is demonstrated using the IEEE4-generator 11-bus test system. Eigenvalue analysis and nonlinear simulation results have verified that the proposed method is capable of displacing eigenvalues into the specified area on the complex plan, and thus the PSS and TCSC controllors can effectively damp low frequency oscillation.