Brown outs
- Thread starter dave81
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Re: Brown outs
Utility line switching and fault clearing operations caused from L-L faults via wind, L-G faults via trees, lightning over loads, etc.
For example if the fault is on your distribution feeder your lights will dim shortly, then go out for a few seconds, come back on dimly go out again, then the third time if the fault does not blow clear you get a lock out, and your power is out until the fault is cleared by the utility.
Maybe Charlie will elaborate.
[ August 04, 2004, 04:29 PM: Message edited by: dereckbc ]
Utility line switching and fault clearing operations caused from L-L faults via wind, L-G faults via trees, lightning over loads, etc.
For example if the fault is on your distribution feeder your lights will dim shortly, then go out for a few seconds, come back on dimly go out again, then the third time if the fault does not blow clear you get a lock out, and your power is out until the fault is cleared by the utility.
Maybe Charlie will elaborate.
[ August 04, 2004, 04:29 PM: Message edited by: dereckbc ]
hurk27
Senior Member
- Location
- Portage, Indiana NEC: 2008
Re: Brown outs
Dave must be in my area except the power just went out and stayed out
Dave must be in my area except the power just went out and stayed out
charlie
Senior Member
- Location
- Indianapolis
Re: Brown outs
Dereck, that is pretty much what happens. The overcurrent devices are set up to protect the distribution lines and that is what you are seeing. In a brownout of that type, a tree limb probably was on the line and it burned clear. During the burning time, you experienced the brown out. If it had been worse, the station circuit breaker would have operated a few times to let it fall away from the lines. If that didn't happen, it would lock out. During a storm like that, the load dispatcher may attempt to reset the substation breaker after the lockout but that is dangerous since you may have fallen lines that are on a car or the ground and assumed to be dead.
Another scenario is a problem with another circuit that is fed from the same transformer that you are. While most of the load is being used for fault clearing, you will see a brownout.
Dereck, that is pretty much what happens. The overcurrent devices are set up to protect the distribution lines and that is what you are seeing. In a brownout of that type, a tree limb probably was on the line and it burned clear. During the burning time, you experienced the brown out. If it had been worse, the station circuit breaker would have operated a few times to let it fall away from the lines. If that didn't happen, it would lock out. During a storm like that, the load dispatcher may attempt to reset the substation breaker after the lockout but that is dangerous since you may have fallen lines that are on a car or the ground and assumed to be dead.
Another scenario is a problem with another circuit that is fed from the same transformer that you are. While most of the load is being used for fault clearing, you will see a brownout.
Re: Brown outs
Thanks for the info guys. Another question is would a TVSS protect any equipment inside the house against these "brown outs" because thats really not a detectable spike in the line is it? I know one of our computers is acting up after that night of storms. Thanks for the help.
Thanks for the info guys. Another question is would a TVSS protect any equipment inside the house against these "brown outs" because thats really not a detectable spike in the line is it? I know one of our computers is acting up after that night of storms. Thanks for the help.
Re: Brown outs
No a TVSS would do nothing for brownouts. Brownout is a undervoltage event. Only voltage regulators (electronic & ferroresonant), MG, and dual conversion/interactive UPS can correct for undervoltage events. However a TVSS can offer some protection from switch transients during the switching operation.
No a TVSS would do nothing for brownouts. Brownout is a undervoltage event. Only voltage regulators (electronic & ferroresonant), MG, and dual conversion/interactive UPS can correct for undervoltage events. However a TVSS can offer some protection from switch transients during the switching operation.
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