Posted by: @transparent

↑

Posted by: @batpred

↑

In my case, my voltage reads are now 240V. They should be 230V, so should I consume less? 

...

The 'Declared Voltage' for LV is currently stated as 230v RMS

..

Since inverters have been pre-certified to G98/G99, they are more likely to decouple themselves from the grid due to low-volts detection.

Ok, my Solis can work to a huge variety of global grid standards. At the moment, it is working on G99, it is something that the engineers asked me early on to confirm before it connected to anything beyond the battery. Is the name for this new standard cenelec something or has bsi come up with a different prefix? I believe this type of info on grid standards is deployed to inverters via firmware updates. 

A small setup like mine (where I do not think I will ever have more than 4kw solar with current panels) will just be expected to have an inverter that backs off if the local grid has a problem, or am I missing anything? To enable normal recovery of the grid, after which my Inverter would connect back to the grid? 

It would be nice to be able to confirm that the standard that will replace g99 is in a future Solis update.. 

Given the underspent for the budget of the Solis inverter and battery 😀 😉, we are considering  the next step: adding PV panels. 

Just wanted to share our schedule of works and get views:  

"We are taking care of the G99 approval with UK Power Networks. We expect to get SEG 8kw export via smart meter in a few weeks..

So I submitted the SEG application to Octopus. Fingers crossed, perhaps it will not be tripped by any silly building regs "checking the checkers" process.

I did not manage to confirm if the G99 standard for low voltage is 230V. And is it replacing G59? 

My DNO (UK PN) seems to supplying 240V in my area... Should my inverter be set to work at G59 in the meantime?

Or would there be another name for UK's 230V?

From what I see, the G99 Type A from ENA is a relevant document.. 

G59 has already been replaced by G98 five years ago.
It's the type certification against which manufacturers of inverters are required to have their products tested.

G99 applies to installations which have more than one G98-certified device,
or where the electricity to be exported exceeds 16A per phase.

The voltage level of the mains supply isn't defined within the EREC G-standards.
The 'Declared Voltage' is already referenced to 230v, and not 240v AC

Thus the interpretation of the Electricity Specifications [...] Act

is that LV must be between 216.2v and 254v AC, single phase.

UKPN, in common with all other DNOs, would normally keep the LV supply at 240v.

That allows greater voltage-drop to occur before G98-certified equipment would remove itself from the grid.

The Electrical Networks Association (ENA) is discussing the possibility of reducing the notional grid voltage to actually be 230v.
That wouldn't require any additional legislation of course.

However, for appliances which adjust their electricity-demand based on watts, such as EV chargers, PCs, televisions and heat-pumps,
the grid current would increase to compensate for the lower voltage.

That creates problems on the 11kV level of the distribution grid...
... which might be reflected in more outages due to thermal overload.

There is no easy answer within the scope of DNOs.

A quick check shows the Solis inverter includes G59/3, G98 and G99 settings.

Based on the fact that the DNO approved 8kW export (so over 32Amp), I understand that I should keep it set to G99. 

If the Solis inverter has a configuration setting labelled G99, then by all means leave it set for that.

But it's a misinterpretation of the regulations by Solis.
Their inverter can't 'know' what other in-house devices are counting towards the export levels approved by a DNO.

This is the sort of detail I feed back to manufacturers.
In this case it would perfectly satisfactory to have configuration 'G98' because that's what they were required to test the inverter for.

Provided that setting still allows you to configure export levels above 16A/phase, then there is no reason why there should be an option to define 'G99' in that field.

Posted by: @transparent

↑

If the Solis inverter has a configuration setting labelled G99, then by all means leave it set for that.

But it's a misinterpretation of the regulations by Solis.
Their inverter can't 'know' what other in-house devices are counting towards the export levels approved by a DNO.

This Solis inverter being rated 8kw and (I expect, as I did not test) also allowing export of max 8kw, it should be operating to g99 when connecting to the grid.

The solis does allow the voltage on the backup port to be independently set. But that is only effective when the grid port does not sense power and the port is fed from dc sources  (perhaps also if the grid power is outside the expected parameters). In normal circumstances, the backup port power mirrors the grid input. 

So I hear the export MPAN that UKPN assigned should be put to use soon. 🙂 

My learning in this process will be to argue more robustly (and immediately) when an electricians' firm (no matter how large) claims they can replace your consumer unit without notification.

I feel that the topic of labelling an inverter installation correctly is important enough to justify adding it to this thread (since critical for safe work by any electrician working in your home in the future). 

Posted by: @transparent

↑

Posted by: @batpred

↑

The regulation mandates labels indicating that there are multiple generation sources in the site.

Would you care to say which regulation you're referring to?

When I was looking for the regs for labelling when introducing an inverter able to export, I started with some of the questions present in the G99 commissioning form like: 

• Generator’s Installation satisfies the requirements of BS7671 (IET Wiring Regulations). 
• Suitable lockable points of isolation have been provided between the PGMs and the rest of the Generator’s Installation. 
• Labels have been installed at all points of isolation in accordance with EREC G99. 

As I wanted to make sure the electrician would have the required labels, I bought a set of labels that was suitable for a PV installation in advance. A subset of these were then applied in and around the consumer unit and inverter. By this I mean something like the set below: 

For guidelines and an overview of labelling, this IET article may help.  Ultimately qualified electricians have access to the current regulations. 

And of course, always make sure to use a registered electrician. 

Posted by: @bash

↑

@batpred 

How was the process for getting Octopus to agree to export without an MCS certificate in the end? Did you have to pay anything?

We also don't have an MCS certificate and I am interested in exporting in the warmer months when our battery bank will have plenty of spare capacity.

Yes, it was a very reasonable payment. Less than 10% of the £3200 the full MCS service would have costed us (of course not directly comparable)! 

Posted by: @batpred

↑

So I submitted the SEG application to Octopus. Fingers crossed, perhaps it will not be tripped by any silly building regs "checking the checkers" process.

This is what worked with a few iterations. 

@batpred 

Thanks for the update.

I'm glad it is possible, I just have to crunch the numbers in how long it'd take to recover the fee at around 8-10p a kWh difference.

@bash My DNO had already issued me with the MPAN.

So while the Octopus process was not a "no win no fee" type of process, it was a calculated risk. Before the summer it will have paid off. Hope that it works for you!