Abstract
When a fault arc occurs in electrical power equipment, the pressure in the latter increases due to the high temperature of the arc. To clarify the phenomenon of internal pressure-rise in the electrical power equipment, this paper shows the influence of the arc current on the energy balance when the former occurs in a closed chamber. Internal pressure-rises in the closed chamber were measured within an arc current of 4 to 12.5kA. Copper, iron and aluminum electrodes were used in the experiments with rod shapes of 20mm in diameter. The main results with the dependence of the arc current are as follows. When using an aluminum electrode, the energy due to the oxidation of the electrode vapor exceeded that obtained from the use of other electrodes. However the ratio of the energy due to the oxidation of electrode vapor to the arc energy was nearly independent of the arc current. When using an iron electrode, the ratio of radiation loss energy relative to total consumption energy was significant, particularly in the low current domain, while when using a copper electrode, since the oxidation energy was smaller than the evaporation energy, the ratio of the energy due to the evaporation of the electrode relative to the consumption energy increased in line with the arc current.
