Study On Method Of Characteristic Gas And It's Application Of Transformer Inner Fault Diagnosis

The operation reliability of the power transformer as the key equipment in electrical power systems, influences operation security of electrical power systems directly. In accordance with the technological difficulties encountered in the process of insulation supervision based on the Dissolved Gases Analysis (DGA), several kinds of diagnosis methods based on DGA are analyzed and the theory of no-code-ratio method are presented to improve the reliability and precision of fault diagnosis of the power transformer. Main research content includes:1) The relationship between common faults and the dissolved gases in the transformer oil are analyzed. Been exposed to the effects of heat and electricity, the oil and the organic insulation material of the oil-filled transformer which is running will be aged and decomposed gradually, several kinds of gases will be produced, moreover the components and contents of dissolved gases are tied up to the type and degree of the fault. The components and contents of gases dissolved in transformer oil can be used to reflect internal insulation faults of operating transformer.2) The fault diagnosis method of power transformer is studied based on dissolved gases. The dissolved gases of the transformer can be used to reflect the heat decomposed essence of the oil and paper insulation. Therefore, the diagnosis method is very intuitionistic and convenient to the fault property.3) The principle and method of no-code-ratio method of gases dissolved in transformer oil are analyzed. If we use this method in the fault diagnoses, there is no need to code the ratio. This method confirms the fault by two ratios, reduces the diagnosing process of the traditional "three-ratio method", makes the analysis and estimates very simple and easy to operate.4) The analysis of the dissolved gases diagnose in the power transformer internal faults and it's application in Dazhou grid demonstrate illustrated that the diagnosis results of the dissolved gases were accordance with the results of hanging examination and the diagnosis was very precise.