Study on the detection and imaging of the residual stress distribution in GIS basin spacer

The basin spacer is the key component of gas insulated metal-enclosed switchgear (GIS), but the crosslinking reaction and cooling shrinkage of epoxy resin compound during the casting process will cause certain residual stress in the basin spacer, which will easily lead to cracking of the basin spacer when superimposed with the operating load, seriously threatening the reliable operation of GIS equipment. In this paper, an automatic detection and imaging system for the internal residual stress of the basin spacer is designed based on the acoustic elastic effect. First, the acoustic elastic coefficients of ultrasonic longitudinal waves at two frequencies ollf 2.5 and 1.5MHz 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 basin spacer is completed, and the acoustic elastic equation under dual frequencies is established to eliminate the thickness of the spacer, which provides a reference for the reliability evaluation of the GIS basin spacer.ll