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.
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.
On Tue, 23 Jan 2018 15:22:35 +0000, email@example.com (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.
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.
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
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!". :-)
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
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.
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
Otherwise I know where my 'leccy is coming from for the rest of my
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.
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
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.
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.
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
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.
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