Research on the Characteristics of Power Frequency Arc in Transformer Oil and Calculation Method for Arc Energy

Arc fault in transformer oil is one of the most serious faults of power transformers. A large number of bubbles and pressure surge caused by insulation oil cracking because of electrical arc may lead to rupture of tank and eventually lead to fire accident. The arc energy is a decisive factor to determine the pressure characteristics inside power transformer and the rupture of tank, and the calculation method of arc energy has been a difficult problem in the industry for a long time. In order to obtain the arc energy in transformer oil, this paper first studies the characteristics of arc current and arc voltage, and puts forward three kinds of calculation methods of arc energy. The arc test platform in transformer oil was built, and the arc test was carried out. The arc energy calculation results and test results were compared and analyzed, and the effectiveness of the arc energy calculation methods was verified by combining with the actual arc fault cases. Finally, suggestions are provided for the calculation of arc energy in transformer oil.