SF6 가스중 결함별 부분방전 펄스의 패턴분석

Abstract

Partial Discharges (PDs) produced by insulation deterioration of power facilities can lead to failure if not detected earlier, so PD monitoring is essential to asset insulation condition in also Gas Insulated Switchgear (GIS). This thesis dealt with the analysis of Phase Resolved Partial Discharge (PRPD) depending on the types of defects which may occur in GIS for an on-line insulation diagnosis of GIS.

Seven types of PD cells

phase distribution, magnitude, counts, and polarity ratio of pulses. PD patterns were completely different from or similar with each other, however the recognition of defect types was possible using these parameters, especially by the polarity ratio of pulses.

protrusion on conductor (POC), protrusion on enclosure (POE), free particle (FP), particle on epoxy surface (PES), void inside epoxy (VE), spacer crack (SC) and floating metal (FM) were designed and fabricated to simulate the insulation defects in GIS. PD pulses were detected by a non-inductive resistor of 50Ω which was connected to the ground of a PD cell in series inside a shielding enclosure, and were transmitted to a personal computer through a data acquisition module with a 2-channel input of 125 MS/s, 8bit, and 250 MHz high cut-off frequency for an applied voltage and a PD pulse.

A PRPD analysis algorithm was designed using a LabVIEW program, and PD patterns depending on defects were identified by parameters