Research On Application Of Measuring Technique Of Sulfur Hexalfuoride （SF₆） Decomposition Products To Judgment Of Fault Diagnosis Of Gas Insulated Switchgear （GIS）

As insulating medium, Sulfur Hexafluoride (SF6) has the excellent insulating andarc-quenching performance, can significantly reduce the equipment size and improve thedielectric strength. It has been widely used in gas-insulated switchgear (hereinafter referred toas GIS). Electrical equipment in terms of design, materials, processes, and maintenance, thereare some weaknesses and uncertainties, resulting in internal defects, when the equipment putinto operation, the effect of heat and electricity, insulating materials decompose, reducesinsulation performance, and even an accident, causing serious economic losses and adversesocial impact. Pure SF6has good stability and is difficult to decompose. However, partialdischarge, spark discharge, electric arc and local overheating can cause SF6decomposition. Atpresent, it has become a hot area of research that by way of analyzing the DecompositionProducts of SF6on Judgment of insulation condition of electrical equipment.At present The Measuring Technique of SF6become more and more matured, includingElectrochemical detection (ECD), Chemical colorimetric, Gas chromatography （GC）,Fourier transform infrared spectrophotometer （FTIR）, chromatography-mass spectrometry（GC-MS）, Dynamic ion method and so on. Especially the ECD has high sensitivity, goodstability, less air consumption, fast response, most suitable for the operation and maintenancepersonnel on-site testing, can more quickly determine the location of the fault and detectionthe internal fault. Application of the ECD measure the Decomposition Products of SF6onJudgment of Fault Diagnosis of GIS are described in the paper. Compare with the othermethods to be a comprehensive analysis.More and more widespread application of GIS, failures have occurred. In this paper listtypical cases of over tests, preventive tests on GIS in Shenzhen Power Supply Bureau.Analysis the effectiveness of measuring technique of SF6Decomposition Products onjudgment of latent fault. Study using SF6decomposition products Detection Technology todetermine GIS equipment failure, complement and improve the GIS equipment operation andmaintenance guidelines for the field test portion.To this end, this paper first discusses the validity of SF6decomposition products detectiontechnology, listed the typical case. Statistics and analysis of Shenzhen Power Supply Bureau,Guangdong Power Grid Company and other units cases. Based on the method of measuringtechnique of SF6Decomposition Products of GIS, to find the relationship between the maindecomposition products and the other insulation fault characteristic parameters. Analysis thecontent trends and insulation fault. Found that, using the Measuring Technique of SF6Decomposition Products can be foundrunning GIS failure, include latent fault. When using the Measuring Technique of SF6Decomposition Products, we should from the initial value, significant difference comparisonand trend change three aspects to determine the effectiveness. Point of failure investigation,should be fully aware of the associated gas chamber decomposition products content changes.Consider the running condition, relay protection, high voltage test to be comprehensiveanalysis, We could judge faults more accurate, to good GIS operation and maintenance.