Pressure Fluctuation due to an Underwater Arc in a Closed Vessel Containing Air and Water

—Influence of Depth of Arc on Pressure Fluctuation—

Abstract

When a fault arc occurs in oil-filled electrical equipment such as transformers in transmission and distribution systems, it generates a flammable gas and a dynamic pressure fluctuation that may trigger an explosion. The purpose of this fundamental study is to investigate the effects of an underwater arc on pressure fluctuation in a closed vessel containing air and water before examining the arc phenomena in the electrical insulating oil. In particular, this paper is intended to investigate the influence of the depth of the underwater arc on the peak pressure amplitude in air and water. The pressure fluctuations in both air and water are measured under experimental conditions involving an arc current ranging from 2.3 to 6.7kA, an arc duration of 20ms and a depth of underwater arc D_arc from 0.255 to 1.135m. Experimental results show that the depth of underwater arc influences not only the waveform of pressure fluctuation in air and water but also the peak pressure amplitude though the same electrical condition of the arc. In addition, the maximum pressure rise in water has a depthwise distribution due to a water movement.