c-C4F8及其与N2混合绝缘气体在典型故障时分解生成物的试验分析

氟碳气体由于其温室效益小,同时具有很高的耐电强度,是较好的替代SF6的气体。使用氟碳混合气体作为绝缘介质的气体绝缘开关和变压器,将成为一类新型的环境友好的输变电设备。因此用试验方法研究氟碳气体及其与N2的混合气体在局部过热、局部放电、火花放电及电弧放电等故障下的分解生成物,并对故障生成物的危害性进行了探讨。试验在自建的模型上进行,故障后的生成物使用气相色谱与质谱联用(gas chromatography-mass spectrometry,GC-MS)的方法来检测。试验结果表明:可稳定存在的过热故障下主要生成物为C2F4、C3F6;纯气体放电性故障的主要生成物为CF4、C2F6、C2F4、C3F8、C3F6;混合气体放电性故障另外产生C3F6N2;故障分解生成物毒性很小。根据故障生成物的特点,提出可根据故障生成物组分来区分氟碳气体绝缘电气设备中的过热性故障与放电性故障。

Experiment Analysis of Decomposition Products in Typical Fault of c-C_4F_8 Gas and Insulating Gas Mixture Containing c-C_4F_8 and N_2

Because of its high dielectric strength,low global warming potential(GWP),fluorocarbon gas is considered as a good substitute for SF6.Electrical equipment using fluorocarbon gas mixtures will be a new type of environment-friendly power delivery apparatus.Consequently,we experimentally studied main components of decomposition gas generated by four major faults: overheating,partial discharge,spark discharge and arc discharge,and discussed the perniciousness of fault decomposition products.Moreover,we analyzed the decomposition products by means of gas chromatography-mass spectrometry(GC-MS) and identified the toxicity of the decomposition gas by searching the toxicity database.It is found that the main by-products are C2F4,C3F6 for overheating,CF4,C2F6,C2F4,C3F8,C3F6 for pure gas discharge faults,and CF4,C2F6,C2F4,C3F8,C3F6,C3F6N2 for mixture gas discharge fault.The toxicity of by-products is low.Finally,the fault type of overheating or discharge can be confirmed based on the main decomposition products.