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 ERRMS and analyzes the relationship between ERRMS and PD energy. Finally, this paper discusses the influence regularity of trace H2O and O-2 on ERRMS.