A robust controller design of SSSC for stabilization of frequency oscillations in interconnected power systems

Abstract

As an AC interconnected power system is subjected to a large load with rapid change, system frequency may be severely disturbed and becomes oscillatory. To stabilize the frequency oscillations, the dynamic power flow control of the Static Synchronous Series Compensator (SSSC) located in series with the tie line between interconnected power systems, is employed. By regarding the system interconnection as the control channel, the power flow control by an SSSC via the interconnection creates a sophisticated method of frequency stabilization. To implement this concept, the robust design method of the lead/lag controller equipped with the SSSC is proposed. In the design process, not only the attenuation performance of system disturbances, but also the robust stability against system uncertainties are taken into consideration. The optimal parameters of the lead/lag controller are obtained by using the tabu search algorithm (TSA), so that both performance and robustness are satisfied. In addition, the technique of overlapping decompositions is applied to reduce the order of the study power system, meanwhile the physical characteristic is still preserved. Simulation study exhibits the significant effect of designed controller on the study four-area interconnected power system under different load disturbances and variation of system parameters.