Research on Full-Circuit Model of Damping Busbar for VFTO Suppression

Using spiral tube damping busbar is a promising method for VFTO suppression due to its effectiveness and ease of installation. To optimize the suppression effect, it is crucial to deeply understand the suppression mechanism and related factors. Thus, a complete circuit model of the damping busbar is established, including all stray parameters and impedance. The method to calculate stray inductance and capacitance between the shell and busbar under high frequency VFTO is introduced. The completely circuit model is established based on SF6 breakdown criterion. The model is applied to a 550 kV GIS platform, and the effect of circuit parameters on suppression is analyzed. Results indicate that the stray capacitance between the busbar and shell also significantly affects VFTO rejection, in addition to coil inductance and shunt capacitance.