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[Starman]

I haven't managed to contact them yet, and am still seeing high voltages every night. Is the voltage recorder a simple plug in device?

If its fitted by your DNO it will be connected before the meter itself to get a completely clean reading as possible. Normally left installed for 1-2 weeks.

We've had numerous voltages in the UK over the years but the most recent standards were 250V, 240V and the EU harmonized standard 230V. Although I can say I quite regularly see ~246V phase to neutral when testing at the bus-bars at secondary substations.

The tap changers at individual secondary transformers are very rarely adjusted probably because of the time and effort required to alter them. So the grid wide voltage is within tolerance but at a more local level you can see higher voltages.

[sevenlayermuddle]

We had a voltage recorder fitted for a different problem at a different house, about 15 years ago.   Being a new-build house, it had the meter cupboard on the outside wall.  Iirc they placed the recorder inside that external meter cupboard, hard-wired to the incoming supply. 

I guess that avoids the results being 'tainted' by dodgy internal wiring, just as happens when we ask BT to investigate a phone fault.

[Starman]

I guess that avoids the results being 'tainted' by dodgy internal wiring, just as happens when we ask BT to investigate a phone fault.

Yeah - I'd take an educated guess 65% of the jobs the first line field technicians get are related to internal issues. I personally more often than not have simply reset an RCD on the consumer unit to restore supply.

For the elderly and infirm you do not mind but given I know for a fact that people are asked to reset their trip switches on the phone it can sometimes be annoying

[c6em]

Every now and then I get a really odd fault.
I think this is one which is a single phase type fault on the HV side of a transformer somewhere remote.
This is a rural area so a TT overhead distribution network fitted with ABC type conductors.
Feed to local substations is 11KV 3phase

Anyway the symptoms are a very low line volts of perhaps 100 volts.
So basically nothing works though you can get an incandescent lamp to sort of glow!

[Starman]

How often does that happen? Anything happening at the time? Weather? Specific appliances on?

[c6em]

I get quite a few short term faults - those where you can actually count the seconds as the auto-reclosers try to close whatever has tripped against the fault several times and then tripping out again each time after a second.  After a few tries that's it until the fault is manually cleared and everything reset.

As to the odd one where I get a left with a 100V supply ......
I suppose I've had it two or three times in the last 5 years - such that I recognize it as being "that fault symptom"
Last time one was during high winds/gales and the other I was out during a normal summerish evening so most things off and came home to find everything a bit 'odd' when I switched a light on - sighed wearily and went to bed - to find things normal in the morning....as you do.
Strangely all these of fault types have been in the evening time.

It's clearly a single phase related type of fault as when I get it, my neighbours on different phases are still on.
The incoming neutral on the TT supply is earthed every now and then round the area at random electric poles.

Those of us on the same phase locally all know each other so when we get an electric cut we ring each other to check that we are all off and that it is a real area phase fault and not just one house as single phase faults seem locally as common as total area-wide failures.

[Ronski]

Well I finally got around to reporting the over voltage fault as it's still occurring every night, UK Power Networks were very disbelieving, but they are sending someone around to take a look. So we shall wait and see what happens.

[Starman]

Let me know what they say I maybe able to offer some guidance.

[Ronski]

Thanks Starman, the guy I spoke to implied it could be something in the house causing it, which I would think would be very unlikely. If it had been in the middle of a bright sunny day then I may have been looking at the solar panel system, but it's not going to be working by moon light is it  . He also suggested it could be the UPS not reading accurately, which of course is possible, if it was at a more suitable time of day I'd happily get my multimeter out to verify.

I'll keep this thread updated with what happens

[sevenlayermuddle]

if it was at a more suitable time of day I'd happily get my multimeter out to verify.

I use a plug-in watt meter, it also reads volts.  And a lot safer than fiddling with multimeter leads at mains voltage at the best of times, let alone when I'm half asleep.

If you haven't already got one I recommend them anyway, a very useful toy for investigating power usage.

PS, I haven't yet reported my own under-voltage, I have been away a lot recently.  Still intend to do so, though.   

[Ronski]

Fortunately I'm very competent with domestic electrical installations, but whether that holds up when I'm tired in the early hours is a different matter. I do have a watt meter so as a quick check I could plug it in and see if it tallys with the UPS., a good idea thanks 7LM.

[Ronski]

I've just had a quick check and have the following readings:

PV Inverter: 249v
UPS: 249v
Watt Meter: 247v
Multimeter: 246v

Now the PV inverter will kick out slightly more than line voltage, but I'm not sure if the display shows line voltage or what it's giving out, so really need to look when it's dark. Also I've no idea how accurate the multimeter is, it's a UNI-T UT70A but I don't know when it was last calibrated or even if it can be.

Looking at the logs UPS logs it went from 252v to 223v at 23:54, then stay around 223v to 06:50 where it jumped to 250v. The UPS logs the voltage every 20 minutes, is it usual to get such big changes? 

[Starman]

I'm wondering - are you in an area without mains supply gas? Neighbors on the local LV network may have storage heating operating on economy 7.

That lower voltage is still within spec but given the weather is quite mild I can see why are some points of the year it would decrease so.

You have PV panels? Are you exporting back to the grid?

[Ronski]

We have mains gas, and being a large estate of the same type of houses I think they all have gas central heating, unless of course people have had it removed, which is very unlikely. We're are very close to a transformer if that makes any difference.

We have a 4kWp array, it was installed back in December and we are exporting back to the grid, so far we've exported 430kWh and generated a total of 790kWh. The export reading is taken from our smart meter which our FITS payment provider refuses to accept, preferring to assume we export 50% of what we generate. We don't have any batteries to store the excess, so it's all exported.

[plexy]

Ronski my friend found that. He put in a big array but was getting way less than he generated as the provider paid a fixed 50 PC. So he bought three old immersion heaters which provide his hot water without needing gas. He's using some 75pc of the electric he generates now but gets paid for exporting 50pc