OT: How does power supply company locate a fault?

I'm just interested in how Western Power, for example, detemines where a fault lies when a power outage occurs. They seem to pinpoint it very accurately within a few minutes, or even seconds. For example, this morning, suddenly, there were three brief power outages in ten minutes, each lasting just a few seconds. But when I rang the fault number the adviser already knew about the fault, which was apparently on a high voltage line, and the outages happened as a result of re-routing the electricity supply.
Is the monitoring equipment so sophisticated nowadays that many/most outages are picked up from the control consoles? I can recall back in 2005 when the electricity company after a storm was out in a rugged Land Rover scanning the power cables bit by bit.
Our supply here in rural Lincs has improved considerably over the past few years, but am I glad I got UPSs for both PCs many years ago! They've kicked in many times.
MM
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On 23/01/2018 13:51, MM wrote:

Automatic re-closing switches and a supervisory control system.
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By deriving the impedance during the the fault, knowing the line construction, the type of fault (single phase to earth phase to phase or three phase to earth) and then doing a bit of maths.
With modern kit a few seconds after a fault the derived distance to fault figure is either on the fault recorder at both ends of the circuit ready to be accessed remotely by an engineer or it is displayed at the control location.
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They don't use RF techniques like time domain reflectometry then? I suppose it is easier with twisted pairs.
--

Roger Hayter

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On 23/01/18 15:22, Roger Hayter wrote:

I thought they did now (but I don't really know). But in the old days they used a wheatstone bridge.
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On 24/01/18 08:52, Tim Watts wrote:

Fairly sure the last time I had a power cut they said they used TDR.
If it works its accurate to a meter or so I think.
--
"When one man dies it's a tragedy. When thousands die it's statistics."

Josef Stalin
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On Tue, 23 Jan 2018 15:22:35 +0000, snipped-for-privacy@hayter.org (Roger Hayter) wrote:

Pointless when you could have a repair team on their way to the location of the fault and persons to apply the isolation and earthing to all points of infeed using the data provided automatically less than a minute after it happened.
To get that info you only need the current and voltage transformers already provided for the circuit protection and pay a few extra pounds to the protection relay manufacturer to enable the built in fault locator function.
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On Tue, 23 Jan 2018 15:05:13 +0000, The Other Mike wrote:

Slightly OT, but generally, with electricity the suppliers *can* know almost "everything". Certainly where faults/outages are.
It's a source of endless amazement that people are still stupid enough to try and steal electricity by fiddling with the meter*. After all, the formula "Energy generated = energy charged for + network losses" is never going to change.
*And it's no use taking the modification off when the meters read ... they can detect it regardless.
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On Tue, 23 Jan 2018 15:52:41 +0000, Jethro_uk wrote:

For modest amounts of "Fiddling" I'd expect it would go undetected provided the 'Fiddler' has left no obvious visible signs of their fiddling activity.
The first house I owned had a meter that very slowly ran backwards when everything was switched off. It was only the equivalent of running a 14 watt load for free as far as I can remember calculating it. It must have halved the cost of running the fridge which used a 30 or 40 watt heating element to drive the absorption cooling cycle (an electric version of a gas powered fridge if you will).
I realised it wasn't enough of an 'anomaly' to concern the supplier (MANWEB as it was before the madness of Thatcherism destroyed the economic, vampire free, running of the nation's vital services) so just accepted "The Free Gift", modest as it was - "Every little helps!". :-)
--
Johnny B Good

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Jethro_uk pretended :

They can measure consumption figures at the consumers meter, they will know what they are feeding down the main supply cable to all of those meters, but none of the measurement systems will have a margin of error.
The error margin means small amounts of theft will not show up. If it did, then those turning a normal domestic house into a place to grow the illegal plants, would be easily spotted - they are not, which is why the police rely on heat signatures, helicoptors and neighbours reporting the smells.
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On 23/01/18 18:31, Harry Bloomfield wrote:

What about all the non metered load - eg streetlights and traffic lights? Any assumptions made about their consumption will have a very wide margin of error (times on, lamps blown etc).
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On Thu, 25 Jan 2018 09:02:34 +0000, Tim Watts wrote:

Are they non-metered ? They must be metered - even if aggregated - *somewhere* ?
Otherwise I know where my 'leccy is coming from for the rest of my life ....
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On 25/01/2018 12:25, Jethro_uk wrote:

Street lights on public roads are not normally metered. The owning authority pay a fixed fee per annum based on the lamp type. e.g 80w sodium etc
Otherwise I know where my 'leccy is coming from for the rest of my

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On 25/01/18 12:25, Jethro_uk wrote:

Do you think every streetlamp has a meter? Or a personal cable?
Former: not that I've ever seen when the cover's been off. Cutout and maybe a timeswitch (less common now with light sensors up top).
Latter: No they don't and I know that for a fact: a) my dad supervised jointers connecting the things - the go onto a joint on the main LV cable. They may take a couple of small cables off this for neighbouring lights). I've also seen this joint recently when the road's been up.
They charge the council based on some sort of estimation - that's all.
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On 25/01/2018 13:28, Tim Watts wrote:

Street lights on public roads are not normally metered. The owning authority pay a fixed fee per annum based on the lamp type. e.g 80w sodium etc
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On Tue, 23 Jan 2018 15:52:41 -0000 (UTC), Jethro_uk

I spent about two years trying to get my supplier to bill my business premises properly. I kept sending them readings, and they kept billing me a stupidly small amount llke £20 (for an office with about 30 staff).
I kept paying in what I estimated I should be paying, and I got letters saying I was overpaying and should pay less. I raised a complaint, and even then it wasn't sorted out.
When the excess got to about £6k, I asked for a refund, and THAT finally sorted the problem out.
This was just beaurocratic incompetence, but it also seems to indicate that there's not much of a system of checks and balances in place.
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When I was a student with SESEB in 1959 fault reporting existed on underground cables.
--
from KT24 in Surrey, England

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wrote:

Fault recorders have been around for a very long time but until about 25 years ago it required interpretation of printed traces to get a reasonable estimate of distance to the fault. Remote interrogation (back then with dialup modem) and PC software brought that ability to any location even the home of the on call engineer. Now you can get the distance to fault data passed over the SCADA system as soon as it is known.
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On Tue, 23 Jan 2018 15:05:13 +0000, The Other Mike

Fascinating. Thanks.
MM
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On Tue, 23 Jan 2018 14:03:04 +0000, Ash Burton wrote:

Auto recloser being tripped and reseting, normally a bit of tree getting too close touching the line and gets vapourised so generally only one brief outage. Just as well the three you had were well spaced if an auto recloser trips more than 3 times in a few minutes it locks out, the fault located and fixed and the recloser manually reset.

Auto reclosers phone home when they trip/lockout.

Not sure I believe that. If a fault around here means that sections of line are feed from a different place by opening normally closed air switches and closeing normally open ones. When it comes to restoring normallity the open switches are closed before the closed ones are opened meaning no interuption to supply. Well almost, after one restoration of normality the lights where flickering away like anything, rang the DNO, engineers at the door a few minutes later, know what that is, off they go, couple of minutes later the power goes for a second or so and comes back solid. I guess an air switch hadn't closed properly and needed re making.

Poles, lines and insulators don't phone home when they fail. They'll know which sections of line the fault(s) are in by which auto recloser has tripped/locked out but not exactly where the fault is. They do have some cunning device that measures ground currents/voltages when the line is energised and the auto recloser trips that gives an indication of how close it is to a fault. Failing that or a report from some one that an insulator is arcing over or a line is down, the only way to find a fault is to walk the line.
--
Cheers
Dave.
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