My statement with regard to the DC Hi-Pot test may have been slightly extreme but not much. At the outset, let me concur[peace] with PWR that any test has its limitations including the VLF Hi-Pot I suggested. I think most would agree[ponder] that we’d like to use a test that has the least...
For small to medium-size systems (the size of most medium/large municipal utilities), I'd recommend either:
Advance Control Systems (ACS) Atlanta or
Open Systems International (OSI) Minneapolis
Both have excellent reputations.
For SCADA consulting to determine requirements and help develop...
We recently encountered a similar condition. Cause was dirty elbow terminators (hence leakage current). You didn't describe the type of Raychem terminators (Raychem didn't use to make elbows) BUT if you have elbows, I'd suggest removing them and leaving bare cables in the clear to repeat your...
Check with the folks at ETAP (Electrical Transient Analyzer Program?). Outstanding program priced in modules (buy what you need) backed by an outstanding staff (150 on staff, 50 are PhDs, I believe).
We have procured the software and had them develop a special GIS (geographic information...
Very interesting problem. With regard to Waross's comments that the voltage sensing transformers may be on the wrong side, he may be right track on that and it should be checked out. You say you have 20 - 30 minutes for retransfer (to allow utility to stabilize). Why isn't it working? Why is...
I would second your request. The common failure mode is "fail-open", due to a broken winding. I would imagine that, similar to power transformers, a winding short (i.e. "fail-short") would also be possible due to insulation deterioration (overheating, moisture, etc.). I've been attempting to...