Bypass an off neutral regulator
Bypass an off neutral regulator
(OP)
The question is: How bad can it get? I think we lucked out with a burnt jumper that protected everything else. How bad have you seen?
When was the last time you drove down the highway without seeing a commercial truck hauling goods?
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Bypass an off neutral regulator
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RE: Bypass an off neutral regulator
Bill
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"Why not the best?"
Jimmy Carter
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
Theory I've heard is that circulating current is more or less directly proportional to the # of taps by which the reg is offset from neutral; anecdotally, even on a single tap offset, the circulating current is reported to be so considerable as to be, as one lineman so eloquently put it, "ugly," to the point that my utility's standing instructions stipulate that the last resort to switching an off-neutral-tap regulator into service is to take an interruption on the line, open the bypass sw and close the reg isolating switches off pot, then return line to service.
Don't know if this helps or not...
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
Here's what I understand:
To switch a properly working in-service voltage regulator out of service without interrupting the supply to the downstream customers [although their voltage may not be all that great]:
1] Place the voltage regulator on manual control.
2] Drive to neutral tap.
Then, and not until then:
3] Close the bypass switch around the regulator, mostly unloading it [current divides inversely as impedance].
4] Open the load side disconnect switch, completely unloading the regulator.
5] Open the source side disconnect switch, removing the regulator from potential.
Return to service is the reverse sequence.
How in the situation being considered the taps would have moved during the out of service period is a mystery I'd want to get to the bottom of...
If the tap drive motor isn't working but the taps can still be cranked manually and your safety rules don't prohibit it, the same procedure can be followed but with the apprentice doing the grunt-work of cranking the taps.
If the taps are actually broken, you're euchred, and the only choice is to dump the feeder while switching the reg o/s - and unless lunacy runs rampant a defective regulator will never get switched INTO service...
CR
"As iron sharpens iron, so one person sharpens another." [Proverbs 27:17, NIV]
RE: Bypass an off neutral regulator
If I intend for it not to step, I do not want the control panel powered from any source.
Another option for a distribution feeder regulator is to simply tie to another circuit or substation and trip the breaker on the circuit with the inop regulator(assuming there is a breaker in front of it) and isolate it for service. For this I will usually cut the controls off on whatever step they are on.
Alan
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
Clearer now?
RE: Bypass an off neutral regulator
Seems in either case a missed step was not to open the bypass immediately after verifying phasing and before closing anything else.....does that make sense with what you are seeing/hearing from the field folks?
Why not close the cutout and the line side regulator switch (no bypass or load side closed) and run it to neutral? Then it would have not been an issue to bypass.
Alan
RE: Bypass an off neutral regulator
If regulator had been run to neutral, there would be no need to bypass. Just close in the other side and continue on.
RE: Bypass an off neutral regulator
Alan
RE: Bypass an off neutral regulator
RE: Bypass an off neutral regulator
Alan