Study on High Energy Discharge Characteristics Caused by Arc Faults in Transformer Turret

The power transformer is an essential equipment in the UHV transmission system. High energy discharge resulting from arc faults in the transformer turret can lead to an explosion, posing a serious threat to the safe and stable operation of the power system. At present, there is a lack of experimental research on arc discharge faults in the transformer turret. The ignition and explosion process remains unclear, which limits the improvement of transformer explosion-proof performance. To address this issue, a test platform of arc discharge fault in the transformer turret was constructed. High-current and high-deflagration capacity simulation short-circuit tests were carried out, and the voltage and current waveforms in the arc discharge process were obtained. This facilitated the quantitative characterization of discharge energy and analysis of the arc energy flow conversion. The test results highlighted that arc energy and arc current are the important factors affecting the voltage boost in the riser. The arc process of casing rupture under high current (1400 A) can be divided into two stages: “smooth” and “sudden”. The insulating oil after high energy discharge and the gas escaping from the oil were analyzed by chromatographic methods. The results revealed that the oil cracking occurs after high energy discharge, significantly increasing various fault characteristic gases in the oil. Among these gases, H2, CH4, C2H2, and C2H4 exhibited the highest total content in the oil, while H2, CH4, and C2H4 presented the greatest range in the escaped gas, accounting for more than 75% of the total volume. This work elucidates the physical mechanism of the internal short-circuit fault of the transformer turret, and holds crucial guiding significance for the transformer explosion-proof design.