Long-term and Short-term AC Treeing Breakdown of Epoxy/Micro-Silica/Nano-Silicate Composite in Needle-Plate Electrodes

Abstract

In order to characterize insulation properties of epoxy/micro-silica/nano-silicate composite (EMNC), long-term and short-term AC treeing tests were carried out undr non-uniform electric field generated between needle-plate electrodes. In a long-term test, a 10 kV (60 Hz) electrical field was applied to the specimen positioned between the electrodes with a distance of 2.7 mm in an insulating oil bath at 30℃, and a typical branch type electrical tree was observed in the neat epoxy resin and breakdown took place at 1,042 min after applying the 10 kVelectrical field. Meanwhile, the spherical tree with the tree length of 237 μm was seen in EMNC-65-0.3 at 52,380 min (36.4 day) and then the test was stopped because the tree propagation rate was too low. In the short-term test, an electrial field was applied to a 3.5 mm-thick specimen at an increasing voltage rate of 0.5 kV/s until breakdown in insulating oil bath at 30℃ and 130℃, and the data was estimated by Weibull statistical analysis. The electrical insulation breakdown strength for neat epoxy resin was 1,763 kV/mm at 30℃, while that for EMNC-65-0.3 was 2,604 kV/mm, which was a modified value of 47%. As was expected, the breakdown strength decreased at higher test temperatures.

A Study on Long-time Electrical Treeing Deterioration Properties According to High Frequency Voltage of Epoxy Resin

“…, 가지형(branch type) [3,4], 소나 무형상트리(pine-like tree) [2,5], 수초형(bush type) [4,6] 그리고 구상트리(sphere type) [3,4] 등이 있다. 이런 독특한 현상은 트리채널 내의 부분방전(partial discharge)에 크게 기여하여 왔다.…”

“…이런 독특한 현상은 트리채널 내의 부분방전(partial discharge)에 크게 기여하여 왔다. 이와 같은 트리실험은 장기적 신뢰성 실험 의 일환으로 연구가 진행 중이며, 트리의 진전을 억제하는 내부조직구조 즉, 나노콤포지트 그리고 마이크로-나노가 혼 합된 콤포지트 [3,7,8 …”

Monitoring and Fault Location Sensor Network for Underground Distribution Lines

“…In [12], Du et al performed a study of how temperature affects to tree growth in epoxy resin insulation, from their apparition to breakdown stages. Park also studied epoxy and other materials to correlate their breakdown strength with temperature [13], showing how higher temperatures reduce breakdown strength. In [14], Kruizinga et al analyzed polymeric insulation degradation due to humidity and other chemical factors.…”