Evaluation of influence of metal wire for ignition on severity of power arc tests - Characteristics comparison between arcs with and without metal wire for ignition

Metal wires are widely used for arc ignitions in power arc tests on electrical power installations, and their material and thickness are selected variously. However, the material and thickness of the metal wire are thought to be influential factors in the severity of the power arc test, because they may change the arc duration and the physical characteristics of arc. In this paper, we made the experiment, where arcs were generated in a closed chamber by two ignition methods. one was with using various metal wires for ignition, and another was without using them, namely with causing dielectric breakdown due to imposing the impulse high voltage. From the results, the difference of characteristics between arcs with and without using metal wires for ignition was investigated, focusing on the arc energy and the internal pressure rise, which can be seen as indexes of the severity of the power arc tests. Consequently, we pointed out that the severity of the power arc tests with using metal wires investigated in this study may be equal to or more than that of the tests with causing dielectric breakdown if there is little difference in the time integral of current during the arcing time. © 2017 The Institute of Electrical Engineers of Japan.