NETA Winter 2022 On-line Cable PD Testing

Imagine this: A new hyper-scale data center is built in rural New Jersey. It has more than 100 25 KV cables. Six months into operation, a cable termination fails catastrophically, and the forensic investigation determines that termination workmanship was lacking. Partial discharge caused tracking, and the cable flashed over. But that’s not the nightmare scenario. The nightmare scenario is that the same team of jointers terminated all 100 cables, and the owner has no idea if they are all on the edge of failing
or if this was the only bad cable.

The owner is left with three options of how they might respond to the crisis:
1. Shut the data center down for weeks or longer and test every cable.
2. Bury their heads in the sand and hope they have no more failures.
3. Test all the cables on-line to identify any suspect cables for further study.

By examining the theory behind on-line testing, this article will show that the third option is the only solution that is both proven and practical at reducing the impact of additional bad terminations down the road.