Some popular technologies for detecting partial discharge（PD） in GIS are described.Some typical simulated defects during GIS operation

such as sharp protuberance on HV conductor

sharp protuberance on inner surface of housing

free particle

floating electrode

void in spacer

and metal particle stuck on insulator surface

etc.

were detected by means of the conventional pulse current detection and ultrasonic detection methods.The phase distributions of discharge pulse and ultrasonic wave pulse

the magnitudes of discharge on different defects under given voltage

and the features and magnitudes of root mean square and periodic peak values of ultrasonic waves from different defects

are respectively compared.The major features of the ultrasonic wave patterns from the two detection methods are hence achieved.These features may be taken as a reference for the application of ultrasonic detection of partial discharge to high voltage test and operation of GIS on site.