Simple Solar & Grid Tie Inverter

Martyn1981

rogerblack wrote: »

1. - CE marking is one thing I do know about - it is not an offence to operate a non-CE marked appliance, only to sell it to customers. The importer would in principle be liable for fines/... - but if it's shipped direct from china...

2. 3. Is this an actual requirement for anything other than FIT/RO though?

I happen to have read the manual for my (new this year) meter, and it will start complaining about reverse energy at very small wattages - 20W comes to mind.

Oh - I quite understand the regulations are insane for small non FIT panels.
I was just wondering - not to put too fine a point on it - if you do it - what are the possible legal consequences.

Hiya Roger, found some guidance from my DNO (Western Power Distribution):

http://www.westernpower.co.uk/Connections/Generation/Installation.aspx

http://www.westernpower.co.uk/docs/connections/MicrogenerationLeaflet_web.aspx

My understanding is that all panels that are connected via a GTI to the grid would need to be notified to the DNO. As they say, they don't need prior approval for sub 3.68kW (16A) systems, but I suspect if the GTI model, certification, or installation technique isn't 'robust' enough, they will deny permission.

Officially, the DNO will need notification of any and every SSEG, FITs RO etc are separate, though admittedly would fail grant funding if DNO hasn't been notified.

I'll check up on 2, but if 3 is necessary, then that drags 2 and 1 into the mix through the paperwork.

Legally, no idea what would happen. Pure guess, if they found out, then they might just tell you to cease and desist.

Back to the meter, the 10A bit I found on the electricians forum. That was the point at which rEd might appear on the meter. Once it appears (it alternates between meter reading and rEd) it's there for good. Obviously it may kick in much sooner (or later) on different models - I'm way out of my limited comfort zone now.

But when you say 20W, do you mean the rEd message, or the solid red light. They're not the same. The solid red light indicates export, rEd appears once the meter has decided to note/report export. Some PV'ers with smaller systems, or systems installed in late autumn/winter might not see rEd at all, or not till generation and export get bigger, despite seeing solid red export light from day one(ish), but again that'll depend on meter type.

I'll try to find some professional opinions. Sorry for all the guesses.

Mart.

Martyn1981

Hiya Roger, just realised that I'd forgotten to say why I found this interesting. I was sent some info from a Spanish resident with his thoughts on mini-micro-generation:

As an example of the profitability of unsubsidised PV on the small scale, say 230W minimum load:
all prices from:

http://store.proinso.net/europe/product_info.php?products_id=538

- 1 x 230W panel = 121 Euros
- 1 Enecsys inverter = 130 Euros
- Mounting frame 40 euros
Total = 291 Euros.

PVGIS says that 230W would generate 354 kWh/year in Madrid and the electricity companies charge 0.15 Euro/kWh for normal grid power excluding connection/subscription/deficit charges which are extra. So the system would pay for itself after 5.5 years. Since the panels and the inverter are guaranteed for 25 years with 0% inflation, it's a no-brainer.

He reports that the problem in Spain is that exporting leccy is currently illegal (Wow!) as the market is controlled by the 'energy companies' and domestic PV would upset prices [see similar story in article I posted on PV in the Australian state of WA this week on 'solar news' thread]. So thoughts have gone to baseload mini systems, sort of what you appear to be thinking about.

Mart.

rogerblack

Martyn1981 wrote: »

Hiya Roger, just realised that I'd forgotten to say why I found this interesting. I was sent some info from a Spanish resident with his thoughts on mini-micro-generation:

As an example of the profitability of unsubsidised PV on the small scale, say 230W minimum load:
all prices from:

http://store.proinso.net/europe/product_info.php?products_id=538

- 1 x 230W panel = 121 Euros
-...

In Madrid - the numbers look even more insane (barking mad, indeed) if you add a couple of fans on the back of the panel, and add a mirror pointed at the panel to double the insolation at midday.

Martyn1981

Hello again Roger, been directed towards 'The Electricity Safety, Quality and Continuity Regulations 2002'

Check out section 22 - Parallel operation

http://www.legislation.gov.uk/uksi/2002/2665/made

So (officially) notification is needed, and therefore all requirements will have to be met.

But, that's not bad news if the numbers add up, since approval should be given. But I'm guessing this would push the costs up a bit.

Fun little exercise!

Mart.

PS I made up mini-micro-generation, but it seemed sort of appropriate. M.

Ectophile

There is a safety issue with grid-tied inverters. That's why they must meet G83 standards.

A poorly designed or made one could be dangerous in the event of a power cut, continuing to feed power into a system that should be dead. A properly designed one will shut itself down in the event of a power cut, and will not start up again until it has determined that the mains is stable again.

Can you guarantee that a cheap non-approved Chinese one will be safe?

rogerblack

Ectophile wrote: »

T

Can you guarantee that a cheap non-approved Chinese one will be safe?

Even the cheapest £40 inverters I have seen on ebay have islanding protection.
Because of their design, it's almost inherent, and not an added feature.

rogerblack

Martyn1981 wrote: »

Hello again Roger, been directed towards 'The Electricity Safety, Quality and Continuity Regulations 2002'

Check out section 22 - Parallel operation

http://www.legislation.gov.uk/uksi/2002/2665/made

So (officially) notification is needed, and therefore all requirements will have to be met..

Interesting. Some things arise.

What's the penalty?
The only penalties I can find are outlined in section 35.

any person who fails to comply with regulation 18(3), 21, 22 or 25(1) and any consumer who fails to comply with regulation 8(4) or 34(2) shall be liable on summary conviction to a fine not exceeding level 5 on the standard scale.

Checking back on the definitions, the only relevant part which can lead to an up to £5K fine for someone doing this seems to be 21/22 - the 'generation' bits.

The interesting bit is in:

22.—(1) Without prejudice to regulation 21, no person shall install or operate a source of energy which may be connected in parallel with a distributor’s network unless he—
(a)has the necessary and appropriate equipment to prevent danger or interference with that network or with the supply to consumers so far as is reasonably practicable;
(b)has the necessary and appropriate personnel and procedures to prevent danger so far as is reasonably practicable;
(c)where the source of energy is part of a low voltage consumer’s installation, complies with British Standard Requirements; and
(d)agrees specific requirements with the distributor who owns or operates the network.
(2) Sub-paragraphs (b) and (d) of paragraph (1) shall not apply to a person who installs or operates a source of energy which may be connected in parallel with a distributor’s network provided that sub-paragraphs (a) and (c) of paragraph (1) are complied with; and
(a)the source of energy does not produce an electrical output exceeding 16 amperes per phase at low voltage;
(b)the source of energy is configured to disconnect itself electrically from the parallel connection when the distributor’s equipment disconnects the supply of electricity to the person’s installation; and
(c)the person installing the source of energy ensures that the distributor is advised of the intention to use the source of energy in parallel with the network before, or at the time of, commissioning the source.

For a small generator meeting 22(2) - not exceeding 16A (about 4kW), which disconnects, and you've notified the distributor, you need to meet part a) and c).
These are basically that it's wired according to normal wiring regs, and has islanding protection.

Interestingly, there seems to be no requirement at all for the supplier to agree with this.

C_Mababejive

just spotted this thread and had no idea that micro generation of this sort was going on. So are we saying that i can connect my own small scale system via a plug in inverter and that hopefully it will address all or a portion of my baseload? If i have an olde worlde whizzy wheel electric meter,does it go in reverse/stop/go slower dependant upon my generation output?

rogerblack

C_Mababejive wrote: »

just spotted this thread and had no idea that micro generation of this sort was going on. So are we saying that i can connect my own small scale system via a plug in inverter and that hopefully it will address all or a portion of my baseload? If i have an olde worlde whizzy wheel electric meter,does it go in reverse/stop/go slower dependant upon my generation output?

In principle.
To comply with the above mentioned law for a small inverter - you need to wire it according to normal wiring regs, ensure it properly disconnects when the supply is disconnected, and notify the supplier.

If you do it without the above, in principle you lay yourself open to a fine of up to 5K, and possible charges of theft, if your meter goes backwards.

(I seriously doubt the latter would be prosecuted, but it's in principle possible, as the price paid for generation is well under the price paid for retail electricity)

On a practical matter, if your baseload never falls below the solar panel wattage, there is no way for them to tell.

There may be other legislation that would kick in to prevent the above, even with notification.

rogerblack

The obligation to get approval from the DNO only kicks in at 16A per phase.
If you had 3 phase, this would be around 12kW.