Impact Of Load Characteristics On PSS Parameter Tuning

This paper introduces four PSS parameter tuning methods including single point of optimal, two points fitting, four points fitting and minimum sum of square of deviations, evaluates the PSS parameters of these units which mainly participate in low-frequency oscillation using four points fitting and minimum sum of square of deviations based on low-frequency oscillations of Yunnan Power Grid. The machine-side load model has a direct impact on acceleration power and frequency, so each coefficient of single machine infinite-bus system transfer function is also derived. This paper analyzes the impact of the load model on PSS input signal, further discusses the impact of the load model on PSS parameter tuning in different conditions and machine-side load rate and verify the conclusions based on 3-machine 9-bus system and the Yunnan Power Grid. Analysis shows that the load model, machine-side load rate and generator output have a certain degree of influence to the PSS parameter tuning, and the degree of influence of the load model changes while the machine-side load rate and generator output are different.