These images show the development of a medium voltage cable failure in an open-air termination at a wind farm in Minnesota. The first image shows non-compliant heat shrink at the termination that was located by the IMCORP's Factory Grade® technology. However, the cable system owner opted to forgo repair, choosing to trust the results of a concurrent HiPot test that passed the cable. The cable was put back into service and subsequently failed four months later at the termination point that IMCORP's assessment identified as problematic.
The second image shows the cable system after the PD activity resulted in failure. The improper shrinkage of the layers at the termination had resulted in a gap between the insulation shield cutback and the stress control tube. As per manufacturers' specifications (IEEE 48), this termination should have been smooth, rather than featuring a gap. This particular situation highlights IMCORP's ability to find defects long before they progress to the point of complete failure. It's worth noting that this is one of many examples where HiPot testing failed to indicate an issue that IMCORP's Factory Grade® technology correctly identified.