Comparative Research on Discharge Gas Characteristics of Typical Defects in Pure Oil Gap

The oil-less equipment is internally insulated by filling with insulating oil. When a discharge or overheating failure occurs, there is a phenomenon that a large amount of H2, hydrocarbon gas, CO and CO2 and other dissolved gases can be produced because of the small internal space. These can cause a explode in severe cases, resulting a huge economical loss. Therefore, a discharge test system for oil-less equipment is designed in the paper. Firstly, the gas diffusion characteristics in the oil after discharge is obtained. Secondly, the gas production test is studied under three typical electrodes, including the plate-plate electrode, ball-ball electrode and needle-plate electrode. Finally, the data of the test is obtained ats at different gap distances and charge time. The research results show that under plate-to-plate electrode discharge, the gas produced by direct pressurization to breakdown is small. The gas production increases with the increase of the gap distance during continuous discharge. The H2 content under 6mm pitch is 9.2 times, 5.9 times and 7.6 times larger than 3mm under discharge of 5s, 10s and 15s, respectively. The C2 H2 content and H2 content of the ball electrode under 6mm pitch gradually increase with the increase of discharge time. After the gas concentration increases, the C2 H2 and H2 generated by the discharge of the ball electrode and the needle plate electrode show a saturation trend. The three electrode discharges all show the law that the gas production increases with the increase of the discharge interval and discharge time. At the same discharge time, the needle plate electrode has the largest gas production volume, followed by the ball electrode, and the plate electrode has the smallest gas production volume. The change law of the discharge gas content in three typical electrode oils is obtained in the paper. There is a great significance for the failure analysis of oil-less equipment under gas production.