Optimal tuning for saturation limiter of a series FACTS device

The external controller (EC) of a series flexible AC transmission system (FACTS) device, which is the series capacitive reactance compensator (SCRC), can provide effective damping of low-frequency oscillations in a power system. The saturation limiter in the EC is used to enforce practical limits resulting from system restrictions such as equipment and component ratings. In this paper, the effect of a saturation limiter on the overall system dynamic behavior is analyzed. Also, a systematic nonlinear tuning method is proposed to determine the optimal values for saturation limits based on the sensitivity trajectory analysis.