Islanding and regulations.

[paulca]

I regret going looking for this now.
https://electrical.theiet.org/wiring-matters/years/2021/84-march-2021/island-mode-earthing-arrangements-new-guidance-in-the-second-edition-of-the-iet-code-of-practice-on-electrical-energy-storage-systems/

The concern is the definition of the BS standard.



PEI.  Prosumer Electrical Installation.

They stipulate that it includes any local power supply and/or energy storage that supplies local devices whether or not it is connected to any public distribution network.

I have not read the full article yet, but I am dearly hoping that these PEI anti-islanding and other BS regulations are not now applying to any and all solar+energy storage, regardless of voltage or whether it is grid tie or not, may actually require anti-islanding equipment.

I could see the UK being the way they are about electrical safety to do something like this.  It could, at it's extreme mean, even a completely DIY solar panel in the garden running a 12VDC system may actually need to adhere to ITE/BS and "prosumer" electrical standards, including certification for anti-islanding.  That would be taking the concern away from the individual as to whether their particular DIY islanding system is or is not safe for the electrical line workers in the area.  Such regulations, if/when the surface for a home owner can get really expensive.  If building control flag a DIY solar panel on a garage roof as requiring PEI anti-islanding certification, that could really ruin your day or cost you a lot of money.

[paulca]

What I am hoping however is that this is just for "Profressional installers" such that (1) they do it correctly to standard when they do it and (2) when doing an inspection, including of DIY consumer/prosumer installation that they can correctly flag "concerns" with the installation in relation to regulations.

These often happen with inspections and tests for house electrics, problems are found that if they were to be done today would be done differently.  Things that were done DIY that if there were ever to be touched by a profressional would be redone entirely, but... importantly, the house can still "pass" the electrical standards with such "observations".

I hope this doesn't go further than that.

I do understand though.  If an electrician performs such an assessment AND flags an installation as having a concern AND it was DIY AND it later burns you house down, the insurance company will absolutely use it to pass some liability to you.

[NiHaoMike]

I suspect the "anti islanding equipment" could be as simple as a transfer switch. The key point is that they don't want someone just hotwiring into an existing circuit, with the chance that it might get connected to the mains later on by someone not aware of that arrangement.

[paulca]

I suspect the "anti islanding equipment" could be as simple as a transfer switch. The key point is that they don't want someone just hotwiring into an existing circuit, with the chance that it might get connected to the mains later on by someone not aware of that arrangement.

Yes.  As long as it remains that "simple" and the "certification" requirements are just that a spark looks at it and says, "Yes, it has a transfer/grid/island isolator".

Its just that BS (British Standard) is a synonym for "Generate work for the civil service and money for the electrical contractors, but screw the consumer"

Consider, on topic, if I want to buy a 2kW hybrid PEI grid-tie invertor system AND have it legally connected to the grid, I have to buy equipment that is (a) pre-certified, (b) I can find a certified installer to install it, (c) I take care of all the building regulations and everything else, all at my cost.

A 2kW off-grid DIY pro-sumer inverter is about £500.  Even going to the "brand names" like Victron etc.

A 2kW on-grid/hybrid pro-sumer inverter is about £3000.  That £2500 is what British standards do to equipment.  Getting those certificates is NOT at all cheap.  So the gear that comes with those documents is 3 to 10 times the price.

The various electrical institutions will see this one way and only one way.  Business.  Work.  Good for the trade.

[jonpaul]

Solar connection anti islanding is a safety critical utility requirement everywhere.

If a backup or solar generation mains 240V is connected to the utility line, that line is,live,even if,the utilitie disconnected for maintenance or there isa power outage.

The utilities workers can be killed ( on a supposed,un energized line)'by a distribution transformer, (12kV pri) energized on secondary side by the backup power source.

Very severe criminal and insurance repercussions.

Thus, commercial solar and backup generator /battery installations must have anti islanding protection.

Neither the utility nor the local building / permit inspectors can approve a non compliance connection

Consult a local liscenced electrician and your town's building permit departmental before proceeding

See the professional electrical forums and Mike Holt.com for solar / backup anti islanding regulations and devices.


Bon chance

Jon

[paulca]

I understand the need for them.

My concern is that the regulations appear to apply whether or not you connect to the grid and regardless of voltage or size.

[gf]

What sense would it make if you are not connected to the grid anyway? The aim is to disconnect the inverter from the grid when grid power fails or becomes unstable. For fault-tolerance, some countries even require redundant disconnect, e.g. two relays in series.

[themadhippy]

regardless of voltage

Ah the joys of uk regulations.If you follow the live working rules to the letter you wouldn't be able to change an AA battery

[ejeffrey]

I don't get what you are pissed about?  Neither the section you quoted or the rest of the document says that you can't have an isolated island of backup power.  In fact it explicitly defines those modes of operation.  It just says that the island must be physically disconnected from the grid when operating as such and that it must continue to have an earth ground, it cannot rely on the earth ground from the disconnected supply.

[paulca]

I don't get what you are pissed about?  Neither the section you quoted or the rest of the document says that you can't have an isolated island of backup power.  In fact it explicitly defines those modes of operation.  It just says that the island must be physically disconnected from the grid when operating as such and that it must continue to have an earth ground, it cannot rely on the earth ground from the disconnected supply.

It's developed a bit since this post.  In part it got worse, in part it got better.  The short of it.

The unit I planned was out of stock.  I accepted, an at my cost, upgrade and got delivery today.

In the interim I kept looking into the regulations regarding terms like "ESS, Grid-tie, islanding, parallel operation".  All of them steer you to G98 and G99 regulations.  Born from EU, now GB, but supported by my locality with G98/99(NI).

Unfortunately the "upgrade" was to a Victron Multiplus, which according to it's design is inherently grid-tie, parallel operation.  The DNO don't state if it's import or export, just that it's a generator in parallel with the grid.

It IS however <3.8kW which classes it as G98.  Requiring only that a qualified electrician "report" it's commissioning within 30 days.  Unfortunately the hardware in question does require a G98 certificate of compliance... and Victron do not have one and probably won't provide one.

I am left with 3 options. 

1. Let the DNO decide. 
2. Use it anyway, just make it temporary consumer installation only, no fixed install.
3. Or return it within my 30day money back guarantee for an inverter only equivalent.  Is will NOT have the "AC-in <-> AC-out" relay and will not be capable of parallel operation at all.  That brings me back to the basic electrical safety and earthing, which I am happy I can work out with my local spark.

[ejeffrey]

I'm not familiar with the UK certification, but this claims to be a G98 certificate for some models of the victron multiplus ii:

https://www.victronenergy.com/upload/documents/Certificate-ESS-G98-1-2021-MultiPlus-II-48V-3k(GX)-48V-5k(GX)-24V-3k(GX).pdf

There are obviously a bunch of different part numbers, and not all of them are covered, but if you got a non-UK inverter and then can't get the certification that it meet UK requirements, that seems to be on you, not the regulations.

[paulca]

I'm not familiar with the UK certification, but this claims to be a G98 certificate for some models of the victron multiplus ii:

https://www.victronenergy.com/upload/documents/Certificate-ESS-G98-1-2021-MultiPlus-II-48V-3k(GX)-48V-5k(GX)-24V-3k(GX).pdf

There are obviously a bunch of different part numbers, and not all of them are covered, but if you got a non-UK inverter and then can't get the certification that it meet UK requirements, that seems to be on you, not the regulations.

It is a UK inverter.  It's only their latest and greatest they have, so far, rather tardily, retro-actively certified.  A lot remain in "Needs more information" status.

However.  More than one person has stated that their DNO accepted their system without the certificate, larger systems too.

The reg update was 2 years ago.  Victron just didn't pre-emptively certify.

It is likely that as they all share the same architecture and some are certified... and... it's so low output which is more likely to let out it's smoke than even cause a blip on the local grid, they will be more annoyed that I asked.

Looking at the inverter on the shelf, the only reason I'm not powering it up right now on a bench power supply is I've had 2 beers.  That's 2 more than the mains voltage limit for me.

I do intend to test it fully.  I believe that is at least afforded at my own risk with such a small prosumer grade unit.  No electrical circuits needs to be created or modified for that to occur.

Sounds plausible, no?

The other way I see it can be justified is... as intended... grid mains is only "shore power" for an otherwise islanded off-grid mobile home... it's just I forgot to put wheels on my garage.

[paulca]

The DNO finally got back in touch.  In summary:

If it is hardwired to their network, ie.  installed on a circuit permenantly, they need to be notified under G98/NI. 

Additionally you need to be careful what you tell them, as they were very much ready to include the total throughput, including grid power of the invertor at 3.6kW and add the 1kW solar as additional 'generation capacity'.  That results in going over the G98/NI regulations and would require prior permission and much tighter regs and more paper work.

Thankfully however when I explained the system a bit more the sofetned and when I asked, "Does it make a difference if I do not hardwire it, but instead have it isolated from my AC except for a single plug socket which I can plug in to charge the batteries and help keep the inverter in phase just for safety... "  They responsed that would indeed make a difference and as far as they would be concerned it's a plug in battery charger or generator and do not require notification, no interest.

Excellent.  Just an earth rod and a coupled of MCB/RCDs.

[kaz911]

I applied for 12 kW solar and 38 kWh battery - with Victron Quattro 10k on UK Single Phase 100A.

I used a "specialist" company for the application to the DNO - and I got approval within 2 weeks but with 5k5 export limit.  The approval is valid for 12 months (so you can install anytime and then notify about installation)

The Quattro is the older generation - so I have external Ziel anti-island device. Basically a control box with 2 "mains" relay's in it.

New "Quattros" and "mulitiplus" have the dual relays.  (A quattro is just a multiplus with 2 x AC inputs)

But the reason for the big application is you "reserve" capacity. The more of your neighbours gets solar and export, the less is available unless the DNO upgrades lines or trafo-stations. So I thought I'd make certain I could fill as much as possible - and then just modify upon installation completion. But until then no-one can claim from my pie... and as the people around have monster big houses compared to ours - they might catch on at some point.

/k