Defect Blog

Each year, millions of people and thousands of businesses are impacted by underground cable system failures. IMCORP is dedicated to advancing the understanding of how these failures occur and more importantly, how they can be avoided.

Apr 16 2012

Non Radial Power Cable Cutback at a Power Plant

By: IMCORP

 

This is the open-air termination of a solid dielectric cable featuring ethylene propylene rubber insulation (the salmon colored section). Initially, this cable was deemed to be in good working order after passing a one-hour, 3Uo VLF withstand test. After that test, the IMCORP Factory Grade® assessment found this cable to be IEEE 48 noncompliant. Subsequent investigation found the PD site to be a non-radial cutback of the insulation shield. This substandard cutback features a very prominent jagged point—an extremely compromising feature because the majority of electric stress will be concentrated there, increasing the risk and likelihood of cable failure.

This cable is a primary output from a power plant. The existence of an electric stress enhancement on one of the terminations is therefore particularly troublesome. Even more disconcerting is that the VLF withstand test passed such a compromised cable. The IMCORP Factory Grade® assessment was able to detect, locate, and assist in the remediation of this potentially destructive PD activity.

 




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