지중 전력케이블 고장사례 분석을 통한 효율적 유지보수 연구

Abstract

Electric railway has used a lot of underground power cables for high-voltage and extra-high-voltage. The underground power cables are inspected and measured in accordance with the inspection cycle for preventive maintenance; however, there occurs electric power-supply failures due to cable deterioration. While the electric power-supply failures except some accidental failures should be prevented by the inspection and measurement, it is not sufficient in the fields. Until recently, the electric railways has inspected and measured with only the megger test of insulation resistance in the off-line, so some causes of deterioration such as partial discharge or water tree cannot be determined in advance. Although Korea Electric Power Corporation has introduced the diagnostic method of very low frequency (VLF) tanδ with operation thorough many tests and research, which is not easy to introduce to the electric railway due to various constraints. There have been several inspection methods that can supplement the constraints in the live wire; however, they are still insufficient to perceive the deterioration such as water tree. In this thesis, cable wise method was proposed for a inspection method in the live-wire state of the electric railways, which could detect not only the partial discharge but also the water tree deterioration. Two-times measurements and analyses were performed by using the proposed cable wise method and the excellence of the cable wise method has been proven in the live-wire sate of the electric railways. If it is introduced into the maintenance method for the underground cable in the electric railways, it is believed that it will greatly contribute to the stability of power facilities.