Abstract
In this paper, partial discharges(PDs), lift off and breakdown voltage were measured when metal particles existed in a model GIS coated with epoxy resin on its bottom electrode, and the measured results were analyzed after comparing with the model DIS not coated. In order to presume the various fault case in GIS, we measured the experimental values with changing some experimental factors, such as the mixture ratio of SF$\_$6//N$_2$, the pressure of the gases, the kinds and diameter of the metal particles, and the coating thickness of the epoxy resin. As a result, the PDIV increased with the thickness of the epoxy resin, while the magnitude of PDs decreased at the same condition. The lift off voltages of steel alloy particles were higher than that of copper particles, and increased wit diameter of particles. Futhermore, the lift off voltages in the case of the electrode coated with epoxy resin were higher than that in the case of the uncoated one. In addition, the thicker the thickness of the epoxy resin was, the higher the breakdown voltage were. Thus, it was confirmed that the GIS coated with epoxy resin on its inner surface could be improved in insulation performance.
본 논문에서는 모의 GIS를 에폭시로 코팅하고, 금속이물 혼입시의 부분방전, 부상전압, 절연파괴전압 등을 측정하여, 코팅하지 알았을 경우와 비교 분석하였다. 또한, 여러 경우의 절연사고를 모의하기 위해, SF$_{6}$/$N_2$가스 혼합비, 금속이물의 재질, 직경, 코팅두께, 압력 등을 변화시키면서 전기적특성을 관찰하였다. 실험결과, 코팅두께가 증가할수록 부분방전개시전압이 증가하였으며, 부분방전의 크기는 감소하였다. 또한 철합금 파티클의 부상전압이 구리파티클보다 높았으며, 직경이 증가할수록 부상전압도 증가하였으며, 코팅두께가 두꺼워질수록 절연파괴 전압이 증가하였다. 이상의 연구결과 GIS를 에폭시로 코팅함으로써 절연성능을 향상시킬 수 있음을 확인하였다.