Influence of Model of Circuit-breaker on Very Fast Transient Over-voltage

Based on a power station, two transient models of circuit-breaker is employed and the very fast transient over-voltage in 550kVGIS is calculated and simulated in the consideration of two different models of circuit-breaker, applying the Electro-Magnetic Transient Program in this paper. The impact of varied models on the values and the frequencies of VFTO in the GIS is intensively focused. It is indicated that the two models of circuit breaker have different effects on the peak voltage of VFTO for different nodes. Under the two operation modes, the deviations of the most voltage spectrum frequency are 5.8% and 0 at circuit breaker. Comparing to the results of the two operation modes, the deviation of operating DS21 are higher than that of operating DS22 because of the changing current flow.