Influence of moisture contents with a low value below 1500μL/L on SF6 decomposition characteristics

摘要

There inevitably exists trace level of water in the SF insulated equipment. Previous research has shown that the decomposition characteristics of SF has close relationship with the moisture content. In order to study the influence of moisture under low volume fraction on discharge and decomposition characteristics of SF. An experimental and testing platform for SF6 gas-insulated electrical equipment was designed in this paper under different moisture contents (147 μL/L, 347 μL/L, 681 μL/L, 909 μL/L, and 1340 μL/L). The influence of moisture on the magnitude of partial discharge caused by metal protrusions defect as well as the content variation of SOF, SOF, SO, CO were observed in detail. The results indicate that average discharge amount and overall magnitude of charge decrease first and then increase with the increasing volume fraction of moisture. The quantitative ordering of the decomposition products is found to be SOF > SOF > CO > SO. HO will promote the formation of all the four products, with a stronger influence on the sulfur-containing products than CO. Besides, the value of Φ(SOF+SO+SOF)/Φ(CO) presents overall increasing trend with moisture content. It ultimately increases to a stable value about 2.5-3 under low moisture condition (<;681 μL/L). The value of Φ(SOF)/Φ(SOF+SO) maintains stable with the variation of moisture. It is about 0.13-0.3 under low moisture content. Thus, the detection method of SF decomposition products should be utilized with the consideration of moisture content.