We attempted to pick-up load by installing 12kV jumpers. We were able to intall one, but we installed the second jumper, an arc-flash occurred. The substation breaker tripped (Line-to-line overcurrent). We've done it before, and nothing happened. Any advise as to what could have caused the arc-flash?
HV switching
- Thread starter Fernando
- Start date
- Status
micromind
Senior Member
- Location
- Fernley, NV. (near Reno)
What was the purpose of the jumpers? If you were paralleling feeders, I doubt you got phases crossed, or you likely wouldn't still be here. If you were energizing a dead line, particularly overhead, there could have been an inductance issue. If you were energizing a 3 phase transformer, and it was wye-wye, some really strange things can happen when all 3 phases are not energized simultaneously, even if it's not loaded.
The possibilities are endless, the more info we have, the more help we can give you.
The possibilities are endless, the more info we have, the more help we can give you.
zog
Senior Member
- Location
- Charlotte, NC
Much more info required to give any advice, but my guess would be your terminations on your jumpers failed. What type of testing was performed on the jumpers before energizing? What were the test reasults? What type of cables were used and how were the terminations done?
wirenut1980
Senior Member
- Location
- Plainfield, IN
Are you trying to tie between 2 feeders from different substations?
What is the voltage on each line that you are trying to tie together? Not sure what your situation is, but if you had a difference of lets say 7 volts on a 120 V base from one line having more voltage drop than the other, that could cause an arc across the jumper.
I would say Jim's thought might be the best bet, but I don't see how that explains the phase to phase target at the substation relay. If you did cross phases from 2 sources I would expect more fireworks than what you described. Did you get a phase to phase target at 2 subs or just one?
What is the voltage on each line that you are trying to tie together? Not sure what your situation is, but if you had a difference of lets say 7 volts on a 120 V base from one line having more voltage drop than the other, that could cause an arc across the jumper.
I would say Jim's thought might be the best bet, but I don't see how that explains the phase to phase target at the substation relay. If you did cross phases from 2 sources I would expect more fireworks than what you described. Did you get a phase to phase target at 2 subs or just one?
- Status