As Soon As The Fault Clears
Good article but this statement was in error:
"For this reason, reclosers are used to automatically re-connect as soon as the fault clears."
A recloser has no way to determine if the fault has cleared once the power is off. It recloses after a delay with the idea that much of the time the fault really will be gone. If not, it opens again, and when it recloses maybe this time the fault will be gone. Etc. So I have replaced the above statement with:
"For this reason, reclosers are used to automatically re-connect after a brief interval. There is a strong likelihood that the fault will be gone when the power is restored. If the fault is still present, the recloser opens again."
This then leads nicely into the existing following discussion about recloser cycling so many times, increasing intervals, and finally just staying open if the fault doesn't clear. — Preceding unsigned comment added by Filmteknik (talk • contribs) 23:03, 27 August 2011 (UTC)
- A nice correction to the sloppy use of language, thanks. David Spector (talk) 11:47, 22 June 2013 (UTC)
Distribution vs transmission
We want to be a little careful - reclosers are only used on distribution circuits, not on the "grid" (high voltage transmission). True, some circuit breakers on transmission may automatically reclose but that's a special-purpose application and HV transmission circuit breakers aren't called "reclosers". --Wtshymanski (talk) 23:27, 28 May 2011 (UTC)
Circuit Breaker Reclosing
"If the only protection system is the breakers at the distribution centres, large areas of the grid would be blacked out while the repair crew resets the breakers."
Something I would like to point out is that this article takes the position (or assumption) that circuit breakers in a substation do not reclose (automatically close). This is not always the case. While most of the points made in this article are valid and factually correct, I must disagree on this point of the explanation. While the recloser does in fact help to break up distribution circuits into smaller, more manageable pieces, many protection schemes involving circuit breakers in distribution substations also apply reclosing to some extent, thus not "blacking out" the circuit and requiring a crew go to the station and reset a lockout. This is not applicable in certain cases, such a breakers protecting transformers, or underground circuits, in which reclosing would not generally be enabled, as faults in these circumstances are much more likely to be permanent in nature, and thus enabling automatic reclosing is more likely to incur additional equipment damage.
As an example, with old electro-mechanical, induction disk style overcurrent relays (ANSI Device # 51; GE IAC##, Westinghouse CO-#, etc.), would have their trip circuits connected in series with a circuit breakers trip coil and with an auxiliary AC reclosing relay (ANSI Device # 79; GE NLR, Westinghouse RC, etc.). The overcurrent trip would open the breaker and start a timer on the reclosing relay. Once the first setpoint was reached (assuming more than one reclose cycle), an output which is connected to that breaker's close coil would then be energized. If the fault persisted upon reclose, then the overcurrent relay would trip again. The reclosing relay would have continued timing to the next setpoint and would reclose the breaker once reached. If the fault was cleared by the original opening, the reclosing relay would continue timing and eventually reset. All this is accomplished in one box now with digital relays, such as those made by SEL, Seimens, GE, Basler, ABB, etc.
A little long winded and meandering, but my point being is that the description may be oversimplifying and not being completely factual in its wording. Reclosers are not the only automatic reclosing devices on distribution ciruits; however they can greatly improve overall system reliability by decreasing the amount of customers experiencing an outage for a given fault. — Preceding unsigned comment added by Greyphox (talk • contribs) 03:42, 18 January 2012 (UTC)
Copied from elsewhere?
I'm concerned that some or all of the "Description" section may have been copied from elsewhere. Parts of it look flaky, for instance "Reclosers address this problem by further dividing up the network into smaller sections" where no prior mention has been made of a network or of dividing it. Perhaps just sloppy writing, but "For instance, the city grid example above might be equipped with reclosers" implies that there's an example above - there isn't. my emphasis, by the way. The rest looks OK, but given those examples that look as though it's been copied wholesale from a larger article somewhere, how much of it's copyvio? I've searched for a couple of phrases and come up with WP mirrors, but I'm not convinced this is original work, Tonywalton Talk 00:21, 5 March 2014 (UTC)
The current link in 'sectionalizers' is to a paper about planning for them.
Would this patent work, as an explanation of what they are: https://encrypted.google.com/patents/US3056006 ?
There are problems with the explanation of what they do. Presumably, several sectionalizers are governed by one re-closer, so they have to both detect fault currents and wait for the recloser, so that:
- the sectionalizer near the problem doesn't open on a running fault current and damage itself
- all of the other sectionalizers don't open at the same time, even when they don't need to
There may also be issues with closing a sectionalizer whose up-stream is energized.
- Re: sectionalizers, I came here to say the same thing. As it is currently explained, a recloser that feeds 3 sectionalizers will open for a fault on any of them, and all three sectionalizers would increment their counters each time until all 3 isolated their circuits, even though the fault was only on one of them. 220.127.116.11 (talk) 02:19, 1 June 2015 (UTC)