Insulating spacer is an important support and insulation structure of GIS. However

the crosslinking reaction and cooling shrinkage of epoxy resin compound during the casting process will cause certain residual stress in the insulating spacer which

in case of superposition wiht the operation load

will likely to cause cracking of the insulating spacer and seriously threaten reliable operation of GIS equipment. In this paper

an automatic detection and imaging system for the internal residual stress of the insulating spacer is designed based on the acoustic elastic effect. First

the acoustic elastic coefficients of ultrasonic longitudinal waves at such two frequencies as 2.5 MHz and 1.5 MHz are tested. By compiling the scanning path of the industrial robot arm

the automatic acquisition of the ultrasonic transmission time of each point on the insulating spacer to be measured is completed

the acoustic elastic equation under dual frequencies is solved to eliminate variable of the structure thickness

the distribution detection and imaging of internal residual stress of insulaing spacer is achieved

which provides a reference for reliability assessment of GIS insulating spacer.