Characteristics of power-frequency arcing faults in transformer oil under different structures

Short circuit arcing faults, as one of the most serious transformer faults, causes an increase in internal pressure of the transformer, leading to explosion accidents and posing a serious threat to the operation of the power grid and personnel safety. Different from the actual structures around the arcing fault, existing research generally adopts the structure of the rod-rod electrode, which limits the accurate study of the characteristics of power-frequency arcing faults in transformer oil. This paper established an experimental platform for power-frequency arcs in transformer oil, designed different structures around the arc, and investigated the arcing fault characteristics at these structures from five aspects: arc discharge, gas generation, dynamic behavior of arc and gas bubble, and pressure characteristics. The results indicated that the structures around the arc directly or indirectly impacted the dynamic behavior of the arc, the latter by influencing the gas flow inside the gas bubble. The dynamic behavior of the arc determined the discharge and gas generation characteristics. Although the structures around the arc affected the dynamic waveform of the pressure by influencing the shape of gas bubbles, the peak pressure was primarily determined by the quantity of gas generated, and the structure had a minimal direct effect on it. The dynamic behavior of the arc at different structures was the main reason for the difference in arcing fault characteristics. The results of this paper provide crucial support for the study of arcing faults in complex engineering structures and have extremely important guiding significance for the explosion-proofing research.