Space charge characteristics of epoxy-creped paper composites

Abstract

In order to study the interfacial effect on space charge distribution in HVDC bushings which impregnated with epoxy resin, samples just like epoxy-impregnated paper-epoxy were prepared by vacuum casting process. Space charge characteristics have been studied by the method of pulsed electroacoustic (PEA) technique at different electric fields and temperatures, including charge polarity, charge amount, the threshold for space charge accumulation. It was found that the polarity of the interfacial charge was related to electric field and temperature. When at 20kV/mm, 313K, there was heterocharge at the interface between epoxy and impregnated paper. But when temperature went up to 353K, homocharge accumulated at both interfaces. However, when at 10kV/mm, there was heterocharge whether the temperature was 313K or 353K. At the same time, threshold for charge accumulation reduced when temperature went up. Above phenomenons were thought to be the result of dielectric polarization and charge injection.

Impact of accelerated aging of epoxy‐Ni nanocomposites on space charge variation adopting pulsed electro acoustic technique

“…It could be due to the increment in the number of shallow traps due to the increment in the free radicals developed due to radiation induced degradation reactions such as chain scissions and oxidation. [ 20 ] Increment in the shallow trap density increases the mobility of the charge carriers, which can aid the charge transportation phenomenon. The slight reduction in the space charge accumulation of epoxy‐Ni nanocomposites during poling time could be due to the increased charge transportation phenomenon.…”

“…Ning et al have studied the impact of UV aging on epoxy‐MgO nanocomposites and have noticed that UV aging leads to higher space charge accumulation. [ 20 ] In general, there is a growing demand for insulation system designers to guarantee the life expectancy of the insulation structure to the power equipment. To acquire confidence on reliability and life expectancy, samples need to be subjected to various aging procedures which the insulant can experience during operation.…”