Abstract：In view of the frequent occurrence of omissions and false alarms of partial discharge insulation

defects in on-site gas insulated switchgear（GIS），the partial discharge multi-source detection test platform was built by using true GIS to carry out the intermittent discharge test of metal contamination defect on the surface of

insulator. Different partial discharge detection methods were used to study the variation of intermittent discharge

characteristics of different discharge degrees. The research results show that the discharge amount of metal

contamination defect shows a trend of first increasing and then decreases with the prolongation of discharge time；

the overall discharge time interval shows an increasing trend；ultrasonic detection method and chemical detection

method cannot realize the effective perception of intermittent discharge of metal contamination defect；the

distribution law of intermittent discharge can be preliminarily obtained from the 200 frequency period ultra high

frequency（UHF）phase-resolved partial discharge（PRPD）spectrum composed of 4 groups of 50 frequency period

UHF PRPD spectrum data；metal contamination defect in intermittent discharge state will not gradually evolve into

breakdown discharge failures. The research results are of great significance for expanding the cognition of

intermittent discharge characteristics and the field detection of GIS discharge defects.

      Key words：gas insulated switchgear（GIS）；metal contamination；intermittent；partial discharge（PD）；multisource feature