This is a very useful forum discussion @l8again 
... and especially so now that we understand you are involved professionally in the data exchange relationship between BEET and Northern Power Grid.

Another member with information from within the energy sector is very valuable here 🙂 

So, yes I take note that you do seem to have given consent for your DNO to access your meter data.
... and please note that I remain doubtful as to whether that complies with the regulations.

I wasn't aware that DCC would provide access to data from a single Smart Meter, even if consent was obtained.

2: Northern Power Grid might like to know that NGED are obtaining aggregated voltage data at intervals of 10-minutes, rather than the usual half-hour intervals which underlies the way in which the meters work.

Whilst not definitive, that's a useful step towards assessing average line voltages across a rolling 10-min period.

3: 

Posted by: @l8again

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I don't buy into the argument that someone knowing my power consumption poses any risk. I can walk down my street and make an informed guess about who is in; out or away without the need for smart meter access.

That's not the scenario which causes concern.

The data which is of most use to a DNO is that derived from rural properties towards the extremities of the 11kV network. These are not 'towns' and don't have 'streets'. There are few ground-mounted local substations, and there is a relatively high proportion of generation assets.

And that rural data is also of greatest interest to 3rd-parties whose motives are malicious. Those include burglars and hostile foreign entities for whom our grid is a 'target', which is a very wide set.

Posted by: @l8again

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Posted by: @l8again

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I don't buy into the argument that someone knowing my power consumption poses any risk. I can walk down my street and make an informed guess about who is in; out or away without the need for smart meter access.

 

 

That's not the scenario which causes concern.

The data which is of most use to a DNO is that derived from rural properties towards the extremities of the 11kV network. These are not 'towns' and don't have 'streets'. There are few ground-mounted local substations, and there is a relatively high proportion of generation assets.

And that rural data is also of greatest interest to 3rd-parties whose motives are malicious. Those include burglars and hostile foreign entities for whom our grid is a 'target', which is a very wide set.

It's worth also remembering (as @transparent partly covered) that there are significant risks more generally with assuming the owner of the home in which the smart meter is installed is necessarily the target, that theft of their physical property is the worst that can happen to them or even that maintaining proper data security is only for guarding against the malicious.

I could wax lyrical about examples of risks in each of those assumptions but for obvious security reasons I won't. Suffice to say a potential burglar using smart meter data to help nick your telly is most definitely not at the top of the dangers list.

Slightly disappointing to see yesterdays data:

Grid max: 254v
Inverter max: 260v
Records: 356

53 resets / 53 >253V grid events

Peak voltage time 13.52 (Both Grid & Inverter measurements within 15 mins)

GivEnergy solar: 28.2 kWh
SolarEdge solar: 9.79 kWh
Total solar: 37.99 kWh

Peak voltage time 13.52 (Both Grid & Inverter measurements within 15 mins

Part cloudy am. Mostly sun pm. 24deg

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Grid voltage was "only" up to 254v. The overvoltage events were all in the afternoon when mostly sunny

Looks like I may need to keep monitoring!

We need a broader view of what's happening when there is Over-Volts.

Are you seeing either inverter 'detach itself from the grid' under G98 rules and then reconnect about a minute after the voltage falls within the specification envelope of 216.4v - 253v?

Is a Fault being reported, and if so, where?

Since you know the max. capacity rating for each solar array, and the total which each inverter actually handled during the day, is there a noticeable difference between the perceived efficiency of the two systems?

I'm trying to ascertain whether the loss of generation from an inverter which was often decoupling from the grid is noticeable.

I'm trying to get clarity on exactly when the inverter detaches.

My understanding is its not precise such as if it hits 253.5v? It's if it reaches a "Sustained" overvoltage... but I don't know exactly what that is. e.g. 253.1v for 5 mins? Or what. I've asked in a GivEnergy forum.

Yesterday it seems to me from the graphic production that it only detached once. But thd GivEnergy prod for the day seems low relative to Solaredge. I'll try a ratio to see variation over my recent monitoring 

So far I'm unaware if/when Solaredge detaches. But presumably it does.

The SE system is 2.28kw

GE is 6.5kw

Different orientation & pitch. GE is 2.85 x size of SE

on comparitive prod there seems a big range. With GE declines when more overvoltage events.

I think it would be more correct to say I've recorded the overvoltage recorded events but they have not all resulted in detachments (as brief and not sustained). So far i can't see detachments get logged - but it might be there.

@tim441 The same thing happened to me 3 days after a new install as I was exporting during the sunny afternoon. My installer said it is something to do with the substation and had me call Electricity Northwest who have to "tap" the substation. He said around my area, this is happening more and more as more domestic PV comes online. As is typical with the UK, companies just don't want to pay to upgrade the infrastructure (what is the standing charge really for?) unless enough people complain. I'm on an AlphaESS system. Hope that helps.

@fleecy yes, tapping down is an option but not automatically the solution.

We can see during the summer we're hitting overvoltage 253v while staying well above the minimum 216v. So in theory looks a good option.

However in winter when there is far less solar as well as increased (and increasing) draw for ASHP, elec heating, EV charging etc there is very real risk that tapping down may lead to under-voltage issues. Hence reluctance to take tapping down as first choice without more checks.

Phase change has definitely improved matters for me with far less overvoltage events since the change.

I will look at my voltage this winter ....i will also look back at logs for last winter

Posted by: @fleecy

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@tim441 The same thing happened to me 3 days after a new install as I was exporting during the sunny afternoon. My installer said it is something to do with the substation and had me call Electricity Northwest who have to "tap" the substation. He said around my area, this is happening more and more as more domestic PV comes online. As is typical with the UK, companies just don't want to pay to upgrade the infrastructure (what is the standing charge really for?) unless enough people complain. I'm on an AlphaESS system. Hope that helps.

When there has been underinvestment in our infrastructure for decades and there are a massive number of new connections it is hardly surprising that the our Grid is struggling. A local DNO manager told me that 75% of his time is now spent on resolving under/overvoltage situations.

By way of a comparison, a canal that runs just north of our town suffered an embankment collapse over the Christmas period. The canal opened sometime between 1807 and 1811. Six months on Keir construction are still lifting tonnes of sand off the adjacent field before adding back topsoil. Work on repairing the canal has yet to start in earnest as the final repair plan has yet to be agreed. The charity is looking at a multi-£M bill.

I have updated my spreadsheet to show peak winter periods for potential undervoltage.

No undervoltage events noted. So in theory might be capacity to tap down. However it would need DNO review to see potential impact on neighbours closer or further away from transformer. 

@tim441 You patently know more than me. If you have time, can you explain the issues as I'm sure to encounter them and the choices you are faced with over the next year. Much appreciated.

@fleecy, tbh i also knew little as at a couple of months ago. So if you read this entire thread, you'll see my journey and helpful inputs by other members. 

Luckily my DNO was helpful & proactive. Switch of phases has very significantly improved the situation. But there is probably still an issue on my local grid at another property that is causing overvoltage. I don't know if the DNO will track it down - or have bigger fish to fry!

@transparent I have sent my latest spreadsheet with historic winter data to SSEN. May have entered a black hole!!

Feel free to share with your contacts if you feel its useful