Voltage Complaint

[Iggifer]

I was doing some very basic work yesterday - replacing some sockets and a light fitting.

On doing initial testing on the RFC i measured the voltage at 254v, I tested a few times throughout the time I was there and was always 254-255v

Is this worth reporting to the DNO? Or pay another visit in a day or two and recheck first?

If it was a couple of V higher I would just report it but it's so close to the limit I'm not sure

 

[Spark123]

Is it causing any issues?

 

[westie101]

Report it, it costs nothing and the DNO will monitor it over a few days to decide one way or the other

 

[Iggifer]

Nope not causing any problems, the only time anyone knew was when I plugged my Megger in.

I'll give the DNO a call then, thanks

 

[JohnW2]

On doing initial testing on the RFC i measured the voltage at 254v, I tested a few times throughout the time I was there and was always 254-255v ... Is this worth reporting to the DNO? Or pay another visit in a day or two and recheck first?

My inclination would be to report it - not the least because you might otherwise be creating work for yourself. What are you going to do if you check in a day or two and find that it's 251V or 252V, knowing, as you do, that it has been seen above 253V? Logically, if you're conscientious, you'd then probably have to make further visits to see if going above 253V was a common occurrence!

Kind Regards, John

 

[Iggifer]

My inclination would be to report it - not the least because you might otherwise be creating work for yourself. What are you going to do if you check in a day or two and find that it's 251V or 252V, knowing, as you do, that it has been seen above 253V? Logically, if you're conscientious, you'd then probably have to make further visits to see if going above 253V was a common occurrence!

Kind Regards, John

All valid points. They do have more work that needs doing so its not a MAJOR issue re-checking but might as well just call the DNO

 

[westie101]

I haven't got the link at home, but the actual requirement is for the voltage to be within limits for greater than 95% of the time measured at 10 minute intervals over 7 days.
So spot checks can only be used as an indication and must be on calibrated instruments.

 

[JohnW2]

I haven't got the link at home, but the actual requirement is for the voltage to be within limits for greater than 95% of the time measured at 10 minute intervals over 7 days.

Is there also a requirement that, in that 'other 5%' of the time it must never (during monitoring) go above some voltage at all (and, if so, what is that voltage?)

Kind Regards, John

 

[westie101]

Is there also a requirement that, in that 'other 5%' of the time it must never (during monitoring) go above some voltage at all (and, if so, what is that voltage?)

Not that I can recall, I'll post a link in the morning for you to see for yourselves as it has a lot of other detail on power quality

 

[JohnW2]

Is there also a requirement that, in that 'other 5%' of the time it must never (during monitoring) go above some voltage at all (and, if so, what is that voltage?)

Not that I can recall, I'll post a link in the morning for you to see for yourselves as it has a lot of other detail on power quality

Thanks. There really has to be an absolute limit, even if it's not formally stated as a 'requirement' in the rules you work to. To take an extreme example, I presume no-one would regard it as acceptable to have a UK supply that was below 253V for 96% of the time but above 300V for some of the remaining 4%!

Kind Regards, John

 

[mfarrow]

I have been contemplating a similar issue, we've got consistently high volts on our street, majority of the time above 245V, up to 255 sometimes.

But I've refrained calling the DNO, because I get few problems and I foresee fewer problems with high voltage than low: heating appliances work quicker, they consume less energy, and induction motors run cooler.

We've had a couple of bulbs blow in the last few weeks, due I'm certain to the array of PVs on the house up the road, but that's about it. Not really worth a phone call IMHO.

 

[TheKeymeister]

It's the season for high voltage complaints, unfortunately the vast number of PV installations are causing havoc everywhere else. Poorly calibrated/not working overvoltage relays in the PV control systems seem to be the usual suggestion, I doubt once fitted they ever get checked....and it's pretty hard to track down.

The usual solution is a tapping down of the transformer, but once high volts season is over, it might result in low volts instead as the PV installations won't be pumping as much back in

 

[JohnW2]

I would imagine that at least one of the reasons (or one part of the reason) for low voltage is the voltage drop to the end of a long supplier main. If that's the case, then the installations concerned presumably suffer not only from low voltage (at some times of day), but also pretty large variations during the day/night - which I would think can be more of a problem than a consistently low or consistently high supply voltage?

Kind Regards, John

 

[bernardgreen]

It's the season for high voltage complaints, unfortunately the vast number of PV installations are causing havoc everywhere else.

If the neighbours of people with PV roof new the potential problems of living next doorbut 2 to a micro generating plant they may object a bit more to glass covered roofs. ( Next door but 2 to be on the same phase ).

I am getting a bit of satisfation from learning that a loud mouthed green freak ( boasting about earning 45p per unit ) with a whole roof PV system is missing the income. The system had to it switch itself off at the peak of the sunshine due to over volting and hasn't yet come back on line. Apparently the reset requires an engineer to call and recalibrate something.

 

[westie101]

Power Quality
Have a read, http://www.reo.co.uk/files/power_quality_fact_sheets_1_-_10.pdf

PV installations
Yep we're having a lot of issues with these, the overvoltage protection is set to 256 volts so we are constantly having to deal with PV users complaining when the system shuts down. One thing, though we have yet to find it, is that if a PV system is causing raised volts to other customers we can require the system be disconnected until the problem is resolved.