Relationship between decomposition gas ratios and partial discharge energy in GIS, and the influence of residual water and oxygen

Partial discharge (PD) with different energy always occurs before a serious breakdown in sulfur hexafluoride (SF₆) insulating equipment. The high electromagnetic energy of PD can cause the insulation gas SF₆ to decompose into various components. Component types and their formation rate are directly related with insulation fault severity. Hence, PD energy can be evaluated based on the characteristics of SF₆ decomposition, which could be further used to diagnose insulation status. This paper focuses on the SF₆ decomposition mechanism under PD, establishes the feature parameter to describe PD energy, and clarifies the feature parameter´s physical significance. In addition, this paper defines the effective energy characteristic ratio ER_RMS and analyzes the relationship between ER_RMS and PD energy. Finally, this paper discusses the influence regularity of trace H₂O and O₂ on ER_RMS.