Effect of discharge trace formation on creepage discharge characteristics in oil/pressboard composite insulation system under impulse voltage application

摘要

Oil-immersed power transformers adopt oil/pressboard (PB) composite insulation system. To downsize the equipment, further understanding about the creepage discharge phenomena is required. In this study, we have investigated the effect of white discharge trace on the creepage discharge in oil/PB composite insulation system. Experimental results show that partial discharge inception voltage (PDIV) became lower after the white trace formation. In addition to this, the formation delay time of the discharge became shorter after the white trace formation. These results can be explained by the gaseous nature of the white trace.