Contents I. Introduction
Power transformer is a core electrical equipment in power system, which plays an important role in the transmission, distribution and use of electric energy. Whether the transformer can work safely and stably directly affects the safety and stability of power system. When a serious internal arc fault occurs inside the oil-filled power transformer, the high temperature arc generated by the fault will release a great amount of energy in a very short time, thus vaporizing and decomposing the transformer oil around the arc into gas bubbles. Then the expansion inertia of the surrounding insulating oil causes a huge pressure difference at the gas-liquid interface, and propagates outward in the form of pressure wave, so that the pressure inside the oil tank suddenly increases. With the accumulation of arc fault energy and the rising of internal pressure, it will lead to the bulge, rupture and even explosion of the oil tank. At the same time, the oil injection, fire and other disasters caused by it will seriously endanger the safety of operators, surrounding equipment and the environment.
