Our PV solar keeps shutting down as the DNO supply via Last Mile Asset Management is goving over voltage i.e. over 230V +10%. If the grid exceeeds 253 V the pv solar is not legally allowed to export.
It has happened before , they denied it but mysteriously it was sorted.
On the Money Saving Expert forum it seems quite a common issue.
Are others on here having / had the same problem & how did you fix it?
JohnV6 2022 CX Plus Four 2025 MG ZS EV aka Trigger
AFAIK the only real fix is for the DNO to change the tapping on the transformer supplying your (and other people local to you) 230V. Obviously there is a cost to this,so they won't do this until they have to. You have to keepttelling them that your supply is over 253V, that they are not meeting their specification and customer obligation and that you are concerned the overvoltage will cause damage to your local equipment (higher voltage means things with electronically controlled power supplies such as kettles will draw more power at 253V than they do at 230V). Eventually they will give in and install a monitor at your house, and confirm (or not) the overvoltage and then go and changed the tapping on their supply transformer.
Of course, part of the problem is that folks with PV systems feeding power back into the grid are pushing the voltage up a little (otherwise the power won't flow out of your house and into the grid). An inverter will raise the voltage no more than about 2V when it is feeding back into the grid. But if lots of people are all doing that then this does not help the DNO hold the voltage within their -6% to +10% on the nominal 230V. However, the fact that you as a PV owner are pushing their voltage up is not an allowed reason for them to be over voltage though.
Persistence seems to be the key technique. Sorry, if you already knew all of this - I don't think there is a magic bullet..
Dave Blue 4/4 1969, Green +4 1953, (different) Green +8 1977
Very interesting, thanks for posting John, and thanks for the comments Dave
We actually had a VO at the previous house because we were close to the substation and had 254 volts + and allegedly it would save us some ££
At the new gaff after much pain we've bitten the very expensive bullet and replaced the inverters & batteries added an immersion control feeder and had to alter a lot of cabling and safety isolators on a system that was only 8 years old (so never paid for itself)
Our DNO is dragging out the revised export agreement and we generated 71.2 kWh today
Yes to harmonise with Europe some time ago our nominal 240 volts was changed to 230v plus up to 10%. I first noticed a breach of this at the boatyard that built my narrowboat at Glasson near Tamworth. Plugged boat into shore power after a cruise and the Combi invertor/charger remained taking power from batteries. Measured incoming power using DVM and saw 261 volts! Spec of Combi showed it only accepted up to 257v. Fortunately I had a backup charger more resiliant to over voltage.
Later heard that as a bodge following regular tripping from new adjacent estate, they had changed the transformer tapping!
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
Our PV solar keeps shutting down as the DNO supply via Last Mile Asset Management is goving over voltage i.e. over 230V +10%. If the grid exceeeds 253 V the pv solar is not legally allowed to export.
It has happened before , they denied it but mysteriously it was sorted.
On the Money Saving Expert forum it seems quite a common issue.
Are others on here having / had the same problem & how did you fix it?
As suggested in video a larger storage battery bank would help if not completely solve, but appreciate the larger extra investment. Couldn't better control of pv output though . The mppt controller directly acting on the dc output of panels and likely integrated into the invertor ought collectively be clever enough to limit excess output affecting local area voltage. In my own experience installing PV panels on a boat, a nominal 12 volt one by itself will happily sit all day in bright sunshine off load showing just over 20 volts.
Accept that new homes being built with pv arrays only exaggerates the situation though. Whether you have an export contract with your electricity supplier or not I believe a pv array will still export power from your home to the local 240 volt distribution area. If this power cannot get absorbed in turn by local homes voltages will rise. I understood this is why there was a blanket limit for an individual homes pv array max output of around 3.7kw before approval was needed.
Richard
2018 Roadster 3.7 1966 Land Rover S2a 88 2024 Royal Enfield Guerrilla 450 1945 Guzzi Airone
We had the same problem which was exasperated by the presence of a very large solar farm in our locality. After much toing and froing the DNO changed the taps on our local supply transformer and we haven't had the problem since.
. The mppt controller directly acting on the dc output of panels and likely integrated into the invertor ought collectively be clever enough to limit excess output affecting local area voltage. In my own experience installing PV panels on a boat, a nominal 12 volt one by itself will happily sit all day in bright sunshine off load showing just over 20 volts.