By placing several artificial defect discharge models in a GIS device

the applicability of ultrasonic and UHF partial discharge detection methods for different defect types was researched. And a large number of field application experiences were conducted for verification. As a result

the applicability of both detection methods for different defect types was obtained. It is concluded that both methods have their own advantage and disadvantage:the UHF partial discharge detection method has higher sensitivity

and the ultrasonic partial discharge detection method has better anti-electromagnetic interference performance. So combination of both methods can fully make use of their advantages to ensure the PD detection reliability and positioning accuracy and support maintenance and safe operation of equipment.