Compared with the ultrasonic partial discharge detection method

the ultra-high frequency partial discharge detection method detects and locates discharge defects in GIS solid insulation more effectively.However

because the position and type of the internal discharge defect cannot be definitely confirmed

the equipment maintenance strategy based on the result from this method is difficult to ensure perfection and accuracy.In this study

a combined ultra-high frequency and X-ray digital imaging method for detecting partial discharge defects in GIS solid insulation was proposed

in which the ultra-high frequency partial discharge detection method is first adopted to detect and locate the internal partial discharge defect

then the X-ray digital imaging method is adopted to visually confirm the defect in equipment maintenance.In a 110 kV GIS live detection in a 110 kV substation

an electrical tree defect within the insulated pull rod of a disconnector was detected by the proposed method

verifying that this method can improve the detection and location of the partial discharge defects in GIS solid insulation

so as to provide reliable defect information for maintenance.