This paper summarizes the internal faults of GIS equipment

describes the principle of ultrasonic diagnosis

and introduces the application of a new GIS ultrasonic insulation measuring device in ultrasonic diagnosis.It lays emphasis on a new fault measuring characteristics based ultrasonic diagnosis technology for internal default of GIS equipment as well as the application experience both at home and abroad.Field diagnostic results demonstrate that this new technology is highly sensitive to the partial discharge signals caused by free particles

vibration

floating potential

etc.in GIS equipment

and it can locate the faults on shell and conductor.