UK DIY Install

[Rickster1978]

No (to your question in bold).

The choice of G98 or G99 is determined by the maximum capacity of the inverter - in your case, your 5.5kW Sunsynk. You will need to apply for G99 approval. I got a response back within a week.

I gave National Grid a quick call today and had a chat with them about my proposed set up. They’ve sent me the G99 A1-1 form to complete.

On first look it doesn’t look too painful. I’ve been trying to find some examples of completed G99 applications on various forums without much luck so far. Hopefully when I come to complete it later on it will be easy enough to do.

 

[SeaGal]

I gave National Grid a quick call today and had a chat with them about my proposed set up. They’ve sent me the G99 A1-1 form to complete.

On first look it doesn’t look too painful. I’ve been trying to find some examples of completed G99 applications on various forums without much luck so far. Hopefully when I come to complete it later on it will be easy enough to do.

Should be straightfoward. Be sure to look up your exact inverter model on the ena type test register and use the ena reference on the form.

ENA Type Test Register

ENA Type Test Register

www.ena-eng.org

maybe this one? https://www.ena-eng.org/gen-ttr/Index?Action=ViewDetail&EID=66519747&tab=search

 

[Rickster1978]

That’s the one I had found it and made a note of the reference so hoping that makes it all a bit easier.

 

[RibbonFox]

Should be straightfoward. Be sure to look up your exact inverter model on the ena type test register and use the ena reference on the form.

ENA Type Test Register

ENA Type Test Register

www.ena-eng.org

maybe this one? https://www.ena-eng.org/gen-ttr/Index?Action=ViewDetail&EID=66519747&tab=search

You have an uncanny knack of answering my questions - in this case, the one I didn't know I needed to ask!

I spoke to my DNO - Northern Powergrid - a few weeks back., They asked me to fill out a huge, complicated form, I honestly didn't understand most of the terminology it (in hindsight, it's probably for large-scale generation). I've not progressed as I was unsure how to proceed, but looking again today, I found another page on their site that splits out the G99 and it's fast-track options. Until finding this, I've heard of forms from other DNOs that are similar, but it now seems that although G99 and fasttrack G99's are common accross the DNO's, they're named/numbered differently by each.

So, I now have the right form, the information I need to fill it out, and some confidence that this is moving in the right direction. Slower than planned, but life always gets in the way. This time it will be a job for this evening but it might actually get completed ?

In the meantime, I've put together a diagram of how I currently think this will all go together (high level - no detail yet). Really, I'm trying to work out where how to prevent exporting to grid, but still allow the inverter to send the excess to the Zappi to consume any excess production. Both the inverter and Zappi expect to monitor the feed with a CT clamp (labelled 'CT' and 'Grid CT') for energy flowing to the grid. If there is, the Zappi should take that energy, to charge my EV. However, the Inverter sees that and stops the export or at least reduces it to 16A, to remain G100 compliant). I'm not sure if I can put the CT clamps in another position or change the architecture to stop this being an issue. Any input would be really appreciated.

What I want, is to prioritise the solar consumption like this:

1. Normal loads (the big DB)
2. Top up the home battery
3. Charge the car (Zappi - only consumes the excess that would otherwise go to grid)

 

[SeaGal]

You have an uncanny knack of answering my questions - in this case, the one I didn't know I needed to ask!

2 for the price of 1

So, I now have the right form, the information I need to fill it out, and some confidence that this is moving in the right direction. Slower than planned, but life always gets in the way. This time it will be a job for this evening but it might actually get completed ?

In the meantime, I've put together a diagram of how I currently think this will all go together (high level - no detail yet). Really, I'm trying to work out where how to prevent exporting to grid, but still allow the inverter to send the excess to the Zappi to consume any excess production. Both the inverter and Zappi expect to monitor the feed with a CT clamp (labelled 'CT' and 'Grid CT') for energy flowing to the grid. If there is, the Zappi should take that energy, to charge my EV. However, the Inverter sees that and stops the export or at least reduces it to 16A, to remain G100 compliant). I'm not sure if I can put the CT clamps in another position or change the architecture to stop this being an issue. Any input would be really appreciated.

I don't know how the zappi works exactly, or why it even needs the generation CT clamp but, based on my experience with my DIY immersion diverter I'd assume...

a) once PV production exceeds house load and battery charging demand, the inverter will start exporting.

b) once the export reaches a level that zappi can kick in (did I read somewhere you need 1500W minimum for class 1 EV charging), then the Zappi will start to charge your EV. This will obviously reduce the export power.

c) as PV power increases (roll on next spring), even if the inverter restricted output power to 16A (3680W), the Zappi would see that export and start drawing more power. The inverter would then see less power being export and ramp up its output, up to the maximum that the Zappi can take + 16A export if there is enough available.

Having said all that, at this stage you are not restricted to 16A under G100. You will only be restricted to what your DNO tells you once your G99 form has got approved. e.g. they may say you can export all 8kW, or they may say you are restricted to 5kW, or whatever. The _minimum_ restriction will be 3.6kW (16A) but likely you will be approved for more unless there are a lot of micro-generation installs on your phase of the grid supply and/or you have a weak network connection.

 

[Rickster1978]

Should be straightfoward. Be sure to look up your exact inverter model on the ena type test register and use the ena reference on the form.

ENA Type Test Register

ENA Type Test Register

www.ena-eng.org

maybe this one? https://www.ena-eng.org/gen-ttr/Index?Action=ViewDetail&EID=66519747&tab=search

Actually, I’m not sure mine is listed on there which is a bit of a worry.

The box states that it’s a SUNSYNK-5K-SG01LP1.EU. but the nearest one to that appears to be the SG03 that you linked to.

Does anyone know if they are different?

 

[SeaGal]

Does anyone know if they are different?

Hopefully Sunsynk support will know the type test approval status. Sometimes a 'family' (of different power) of inverters can get approved in one go ?

 

[Rickster1978]

I’ve had a response on my G99. Can I just check that the limit would be on the export to the grid? I know that the household usage is regularly around 5kw so keen to ensure I can draw that much from the battery. I really don’t want to export anything at all.

 

[SeaGal]

now that's the first posting on this forum that I can read without my glasses on ??

For sure, the DNO is only concerned about export to grid, hence you will be able to draw as much as the inverter can provide to the house from battery and/or PV...

But what an appallingly written answer . What do they mean by "I can allow the 5kW". 5kW is not a noun. I am guessing they mean they will allow you to install the Sunsynk 5kW inverter?

But then the next sentence doesn't make logical sense to me. Do you have any other inverters already connected at your premises? If so, it would appear they mean they will only allow you to export an additional 3kW from your 5kW inverter (achieved by invoking its G100 compliant grid export feature).

But, if you don't have any existing equipment they are technically wrong. You are legally allowed to export up to 16A on one phase at nominal 230V, which equates to 3680W and is usually referred to as 3.6kW.

<rant>
And the DNO needs to send their employees on an English course before letting them write to customers... "ran" is not the past participle of "to run". It should be "run", as in "I have run a system study..". Then there should be a full stop or an "and", not a comma. And what does "as long as limit this" mean? ... as long as you limit this? as long as the fairies at the bottom of the garden limit this? as long as the inverter limits this (in which case the 's' is also missing)
</rant>

 

[Rickster1978]

No other inverters at all. This is the first one. I did wonder why the 3kw was referenced as I would have thought I could do 3.68kw anyway.

Do you think I should go back and confirm. It’s not even a 5kw inverter that I’ve got, it’s a 5.5kw so those numbers aren’t right either.

Just wondering if I should go back and ask for confirmation around the 3kw based on the numbers you’ve referred to above SeaGal.

 

[SeaGal]

Just wondering if I should go back and ask for confirmation around the 3kw based on the numbers you’ve referred to above SeaGal.

Definitely

 

[kommando]

Odd, I cannot see how they can restrict you to less than 3.68kw export as you could do that without asking permission with G98. But for keeping them happy then just amend your application and set the Sunsynk to 3Kw max export. I think my record export is at 200W with a solar diverter to hot water so the export limit could be near to nil for me. What it does tell you is the local network is near to its limit, during peak PV output your mains voltage will be high due to all the local export so your Inverter may disconnect. Even at midnight my local transformer is churning out 246V so I have upped the allowable high AC voltage on my inverters to eliminate the disconnects. If the DNO ever complains I have logs of all the voltages showing they have set the transformer too high. If they want me to drop my settings they can reduce the transformer to 230V as per their own specs.

 

[SeaGal]

I cannot see how they can restrict you to less than 3.68kw export as you could do that without asking permission with G98

Exactly

I have upped the allowable high AC voltage on my inverters to eliminate the disconnects.

What is your grid voltage when you get the disconnects at the inverter, which will be 262V ?

If it is above 253V, then the DNO is failing in their statutory obligations under the Electricity Safety, Quality and Continuity Regulations 2002 (ESQCR). You should inform them of this and they should re-tap the 11kV to LV transformer.

If it is not above that voltage, then it sounds as if you have a local voltage-rise issue. You may need fatter cables to your inverter if you are rising over 9V between your CU and the inverter.

If they want me to drop my settings they can reduce the transformer to 230V as per their own specs.

They will drop it if they exceed 253V at the main DNO cut-out fuse. The 'specs' for the UK is 230V -6% / + 10%, so effectively 216V to 253V. However when the UK voltage was harmonised with mainland Europe back in the 1990's (we were 240V, they were 220V) nothing actually changed - the DNO's equipment is still be centred around 240V. The DNO's are more concerned with too low voltage than too high, so running the network around 240V, rather than 230V gives them more leeway.

 

[Rickster1978]

Definitely wants 3kw. Seems a bit odd but as I don’t really need to export then I guess it’s not a problem.

 

[SeaGal]

Did you ask them why and point out that you can export 3.6kW without approval if you had G98 compliant inverter?

 

[Rickster1978]

Yep, made it fairly clear but got the very short and sharp response.

This is what I said but I’m trying to not get an argument with her but it does seem wrong.

 

[SeaGal]

Ask for a reason and escalate it if it is not forthcoming. That's not right IMHO, unless there is some specific reason that we are unaware from - in which case it would be good to know for future reference.

 

[PanEnio]

It may look like I am hijacking the post. It is not my intention. I see some similarities of my case to @Rickster1978 and DNO response. Although mine is probably a bit more specific.
I have send to my DNO (National Grid) form A1-2 with 5kW inverter & 10kWh Battery info. The response from network planer was:
You can connect the inverter you’ve specified with the battery providing the battery is connected to this inverter and the export is limited to 3.68kW by G100.
Could you complete the attached Appendix B and provide a SLD.
Although the inverter is capable of setting Zero export or whatever value like 3.68, it does not have G100 approval on ENA list website just G99. So I can not really proceed this route. I have asked inverter manufacturer if they can submit G100 to ENA. They promised to do it. But nobody knows when we can see tick against G100 on ENA web.
Since application with Export Limiting is not possible at this time I thought about another route. Namely I explored procedure G99 SGI-1. The G100 is not required for that and I could use post-notify. So, it means limiting inverter output (not export) to 16A/3.68kW. I understand that 3.68kW will be the max what inverter will be capable to process from PV or battery to the house. I am hoping in the future when G100 is approved on ENA. I will be able to reinstate the original Registered Capacity to 5kW and just limit the export to 3.68kW. Or perhaps DNO will upgrade network so we all will be able to do 5kW
Did anyone went with SGI-1 procedure and has some experience to share?

 

[SeaGal]

Welcome!

The response you received (in purple) is what I would have expected Rickster's one to have been, if the network would not support the full 5kW output.

Out of interest, what inverter do you have? I have seen cases where the G100 box is not ticked on the ENA website, but the manufacturer has already got G100 certification. I guess that is not the case with yours, as you say 'they promised to do it'

I just looked at the national grid's SG-1 fast track page and it seems to be very similar to G98 in that they say it is "This is a fit and inform process. Provided all the points above have been met then an installer can fit the equipment and notify the DNO using an A3-3 form."

So, although that would restrict your house usage, it looks like you can just go ahead and tell them about it after commissioning.

With regard to

But nobody knows when we can see tick against G100 on ENA web.

I don't think you will need to actually see that appear on the ENA type test register. Provided the manufacturer can supply you with their G100 cert you should be able to submit that the your DNO and I'd be suprised if they don't accept it. The reason for saying that is that when I did my G99 application, despite the inverter having the G100 "tick", the DNO asked for a copy of the G100 cert.

In the meantime, your plan to go for SG-1 sounds a sensible workaround.

 

[Rickster1978]

The SLD I need to update. Am I correct in assuming that’s the line drawing I submitted? Am I also correct that I just need to make a note on it to show that the export to the grid is going to be limited to 3kw?

I won’t really be exporting so I’m ok with restricting it although I think it’s a bit ridiculous based on being allowed to do 3.68 under G98 without any approval from National Grid.