Effect of Magnesium Hydroxide on Voltage Lifetime of Epoxy Composites.

SUMMARY In general, a polymer insulator subjected to high voltage reaches breakdown as a result of the development of electrical trees. Magnesium hydroxide, a metal hydroxide, has the property of releasing water of crystallization at high temperatures. If the energy of a partial discharge is used by the decomposition of magnesium hydroxide, the growth of electrical trees will be inhibited and the lifetime of the polymer insulator can be expected to improve. Therefore, we have studied the effects of magnesium hydroxide on treeing. We confirmed that the electrical breakdown time of epoxy resin with 30 parts per hundred (resin) of magnesium hydroxide was 100 times longer than that of epoxy resin without it. Magnesia was detected through electron beam diffraction analysis of the filler particles located near the electrical tree, and it was found that a dehydration reaction took place in the magnesium hydroxide. In other words, as an explanation of the effect of inhibiting an electrical tree, the effect of the energy dispersion of a partial discharge is suggested along with the barrier effect of the fillers. [ABSTRACT FROM AUTHOR]