柱上高圧開閉器内部の消弧グリッドでの冷却現象の伝熱評価

Abstract

Focusing on the cooling of the arc splitter plate after arc generation in the pole mounted switchgears, the heat transfer phenomenon was clarified. Experiments were carried out on a pole mounted switchgears with load currents of 600 A and 800 A, and the heat transfer phenomenon was evaluated from the surface temperature of the iron arc splitter plate measured with a radiation thermometer. From the analysis results, it was found that the plate was cooled by forced convection due to the expansion of the air due to the arc for about 5 s after arc interruption, and then cooled by natural convection. Immediately after the start of the experiment (about 600 s from the start), the effect of the arc on the air is large, and the ratio of cooling by forced convection to total cooling amount is about 0.5 to 0.75. When the melting area of the iron arc splitter plate increases, the ratio of heat transfer rate by forced convection becomes about 0.3 to 0.55. In addition, after the experiment with a load current of 800 A, it was confirmed that the iron arc splitter plate melted and melted down over a wide area. It is thought that at a load current of 600 A, the melting area of the iron arc splitter plate was small enough to melt down, but at 800 A, when the arc energy increased, the melting area of the iron arc splitter plate increased and melted down. It was clarified that the heat transfer phenomenon in the arc-extinguishing plate is affected by melting.