We recently had a terminator fail. It is an outdoor porcelain type that is connected in parallel with a duplicate terminator to a common out going aerial feeder. We suspect the rubber boot on the top of the terminator failed and allowed water to seep in. There were two distinct explosions a minute apart, we located it, and replaced it. See attached pictue of what we had after cutting it open. Any one had simular problems? It has been in service around six years. Any comments would be appreciated. Thanks
35 KV termination failure
- Thread starter jimmac49
- Start date
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zog
Senior Member
- Location
- Charlotte, NC
Looks like the insulation was damaged about 2 inches down from the end which is where the tracking starts The semicon cutback shows some poor workmanship, which may have started tracking.
i will show this to some cable gurus I know and get thier thoughts.
i will show this to some cable gurus I know and get thier thoughts.
zog
Senior Member
- Location
- Charlotte, NC
Yes it may have caused that damage. Whats the spring from, havent seen that in awhile.
Zog the termination uses a spring-loaded elastomer filler as strees control and moisture sealant, and allows expansion and contraction of the cable. Attached is a shot of the top of the porcelain looking down. The spring sits on top of the steel ring you see inside the terminator.
Jim
Jim
jrannis
Senior Member
- Location
- Fort Lauderdale/ Miami
Nice table. Is that Maple?
wirenut1980
Senior Member
- Location
- Plainfield, IN
jimmac49 said:
Jim, I am thinking that maybe there was contamination inside the terminator that was enough of a conductive path to track from the overhead phase conductor entering at the top down to the concentric neutral of the underground cable. That would explain the blowout at the top and bottom. Not sure what caused the tracking...most of what I've seen is that cracking in the porcelein leads to contamination inside, but usually the porcelain ends up blown out too.:-?
BAHTAH
Senior Member
- Location
- United States
35kv term failure
35kv term failure
Jim, when I was working for DWP in LA we did some 34.5kv bus ties with 2000Kcm synthetic cable (our system was all Lead cable, oil or gas filled) which was new to us. The terminations that would take three shifts (Lead cable) would take only one shift with the new cable and terminations. I do remember the manufacture having us cut the filler ( the factory had people on site as we made the terminations) because there was to much pressure from the spring to bolt the bowl in place. I would suspect that your mositure theory is correct. I would not think a contaminated termination would last six years. It would be interesting to know if the manufacture has changed their design of the rubber boot at the top of the pothead.
35kv term failure
Jim, when I was working for DWP in LA we did some 34.5kv bus ties with 2000Kcm synthetic cable (our system was all Lead cable, oil or gas filled) which was new to us. The terminations that would take three shifts (Lead cable) would take only one shift with the new cable and terminations. I do remember the manufacture having us cut the filler ( the factory had people on site as we made the terminations) because there was to much pressure from the spring to bolt the bowl in place. I would suspect that your mositure theory is correct. I would not think a contaminated termination would last six years. It would be interesting to know if the manufacture has changed their design of the rubber boot at the top of the pothead.
Thanks for the feed back guys I appreciate it. We have around 50 of these termination at one site and we have been inspecting them all. We found a few more bottom boots cracked and split, the tape shield was also visible through the splits. We are going to replace, them probably with cold shrinks. The basic design of the porcelain type remains the same, as far as I know.
Jim
Jim
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