Coordinated Design of Power System Stabilizer and Damping Controller of Thyristor Controlled Series Compensators in Multimachine Systems

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)or those installed on thyristor controlled series compensators(TCSC),are well tuned.Based on a simplex-simulated annealing(SSA)algorithm,an approach is presented for optimal coordinated design of parameters of PSS and TCSC damping controller.As the simplex formulation is taken as the local searcher in an SA framework to enhance searching efficiency,the SSA algorithm has intrinsic advantages of both fast searching ability as simplex method does,and the ability to reach a global optimization inherited from the SA method.By considering multiple representative operating conditions in constructing the objective function,robustness of the damping controllers is ensured.A valid example is demonstrated on the 4-generator 11-bus test system.Eigenvalue analysis and nonlinear simulation results verify that the proposed PSS and TCSC damping controller can provide sufficient damping to low-frequency oscillations in different operation modes.In addition,the SSA algorithm is insensitive to initial values and it converges to the optimal solution much faster than SA method.