Abstract:Given the frequent missing and false alarms of partial discharge insulation defects in on-site gas insulated substation (GIS),intermittent discharge characteristics tests are conducted in this article to study the discharge characteristics of common solid insulation defects inside GIS at different temperatures in the actual operating temperature range of GIS. In this paper,the platform of GIS electric thermal coupling intermittent discharge simulation test is built with the pulse current method,ultrahigh frequency (UHF) method,ultrasonic method and gas characteristic component detection method used in combination to obtain and analyze the intermittent discharge characteristic data of solid insulation defects at different temperatures. It is found out that both UHF detection method and pulse current detection method can effectively detect the intermittent discharge UHF signals of test defects at different temperatures,while ultrasonic and gas characteristic component detection methods are not applicable to effectively collect effective discharge data. The intermittent discharge voltage of metal pollution defects on the surface of solid insulation and internal air gap defects shows a negative correlation with temperature. The intermittent discharge voltage of pollution defects shows a significant trend of linear decrease,while the intermittent discharge voltage of air gap defects shows a significant decrease first and then a trend of slow-paced linear decrease. The average discharge capacity and UHF signal amplitude of intermittent discharge of pollution defects exhibit a positive correlation with the increase of temperature. The intermittency of pollution defect discharge increases with the extension of discharge time at different temperatures,while the interval of gap defect discharge can change from second level to microsecond level at 26 ℃,40 ℃ and 50 ℃,posing a risk of breakdown discharge. The research results obtained in this article further enrich the theoretical system of GIS intermittent discharge and improve the effective diagnosis rate of on-site GIS intermittent discharge.