Fault Diagnosis Method of Oil-Immersed Transformer Based on the Production Pattern of Free Gas and Dissolved Gas in Oil

Monitoring the operating state of oil immersed transformer by free gas is an effective means to prevent equipment from burning and explosion. However, there is no research on the production pattern of free gas under different fault conditions. In this paper, the production pattern of free gas under discharge fault and thermal fault is obtained through experiments, and the dissolved gas in oil is collected and analyzed after the test. It is found that under severe faults, most of the characteristic gases generated by the insulation system cracking will escape to the top of the oil tank and be collected, while the characteristic gases dissolved in the oil are less. The existing dissolved gas analysis method cannot diagnose the transformer operation state through the component content of free gas, and the concentration of dissolved gas in oil is low, so the dissolved gas analysis method ca not accurately diagnose the transformer fault type. And the production pattern of free gas varies greatly under different faults, by analyzing the component content of free gas and dissolved gas in oil, the fault type can be accurately diagnosed at the early stage of serious fault.