PV solar cutting out due to grid over voltage in IP11 post code

JohnV6

My DNO provider is Last Mile Asset Management and historically there was a problem with the grid being over voltage & shutting down my pv generation.

I have of ocurse written to last mile to complain again.
You can see that on Sunday it was a nightmare.

The solis data tracker runs on a 5 minute cycle so can miss up time. But my smart meter monitor runs on a 15 s cycle rate and that shows a cycle of generation for 15 s then off line for 30 or 45 seconds. 

How have others convinced their DNO & especially Last Mile to upgrade the local transformer?
If you are a Last Minute user & especially if you live in the Trimley St Martin are covered by IP11 I would love to hear from you.

Robin9

Do you have any evidence of the supply being in excess of 230 + 10% 

There is some adjustment available to the voltage output of your local transformer - a relatively easy task  - if that is the issue.

You may get more response from the Energy Forum and/or a local Facebook group

JohnV6

Yes I can see it on the app for the inverter & graph it.
I'll try to copy & post this on the other forum.

JohnV6

My DNO provider is Last Mile Asset Management and historically there was a problem with the grid being over voltage & shutting down my pv generation.

I have of ocurse written to last mile to complain again.
You can see that on Sunday it was a nightmare.

The solis data tracker runs on a 5 minute cycle so can miss up time. But my smart meter monitor runs on a 15 s cycle rate and that shows a cycle of generation for 15 s then off line for 30 or 45 seconds. 

How have others convinced their DNO & especially Last Mile to upgrade the local transformer?
If you are a Last Minute user & especially if you live in the Trimley St Martin are covered by IP11 I would love to hear from you.

MWT

JohnV6 said:

My DNO provider is Last Mile Asset Management and historically there was a problem with the grid being over voltage & shutting down my pv generation.

Do you have any data on the voltage state, and do your neighbours also have solar PV ?

JohnV6

One neighbour does but they just moved in last week.
I have the grid voltage the inverter tracks it. 

QrizB

Have you had your installation checked, so you're sure the problem is in the DNO network and not inside your house? The inverter only knows the voltage at the inverter, the voltage at the meter could be quite different.

You've got a smart meter? Can you get a voltage display on it?

MWT

JohnV6 said:

One neighbour does but they just moved in last week.
I have the grid voltage the inverter tracks it. 

If you can share the voltage data it would help in terms of seeing if this is only occurring during peak export times or if it is an issue 24/7.

With regard to your neighbour, the solar PV installation  will probably have been exporting even if they had not yet moved in, or is this a new, recent install?

Robin9

To the Solar experts on the forum.

What would you expect to be happening ?

Would the inverter have a default supply it was expecting form the Grid. ? Would this be (say) 250 volts - leaving a safety margin of 3 volts from the max of 253. ?

1) When there is a failure of the Grid supply ?   Does the inverter recognize this and cease trying to export ?  What would happen with the inverter when the supply is restored. 

2) What happens when the local solar generation exceeds the grid demand?


On another aspect  -  what is the relationship between Last Mile and the DNO for the region - UK Power Networks ? This something new to me.

QrizB

Robin9 said:

Would the inverter have a default supply

it was expecting form the Grid. ? Would this be (say) 250 volts - leaving a safety margin of 3 volts from the max of 253. ?

The UK specs for inverters (G98/99) set a maximum and a minimum voltage tolerance. The maximum is a little bit higher than the maximum grid voltage, to allow for losses between the inverter and the DNO network.

The exact values are published in the spec, but I don't have a copy readily to hand. It can be Googled.

Above or below that voltage, the inverter cuts out until it can see that the voltage has dropped.

This appears to be what is happening with the OP's inverter. I've had it happen with one of my inverters too, on sunny low-demand days (for good reasons that I'm not bothered about). Switching the immersion heater on usually drops the voltage at my CU enough for the affected inverter to cut back in, at least until the HW tank is hot!

Robin9 said:

1) When there is a failure of the Grid supply ?   Does the inverter recognize this and cease trying to export ?  What would happen with the inverter when the supply is restored.

The same G98/99 specs require that the inverter cuts out in the event of grid failure. I think it's within a cycle, so 1/50th of a second, but that's from memory.
And it will reconnect automatically when the grid comes back, after a brief pause to monitor things.

Robin9 said:

2) What happens when the local solar generation exceeds the grid demand?

In principle the local transformer should allow excess generation to flow back up the network to the next higher level, but I'm not sure if it works like that in practice. You'll need a DNO systems engineer to answer that one authoritatively.

Robin9 said:

On another aspect  -  what is the relationship between Last Mile and the DNO for the region - UK Power Networks ? This something new to me.

That's for the OP to answer, but I suspect the OP is on a private power network of some sort.

JohnV6

I can't see voltage on the smrt meter display.
In a power failure the solar shuts down as required by law.
We live on a newish estate. Last Mile Asset Management is our DNO.