Navitron Renewable Energy and Sustainability Forum

Energy/Electricity Storage and Use/Grid Connection => Grid-connected Renewables => Topic started by: Ted on January 11, 2010, 10:56:21 PM



Title: G83
Post by: Ted on January 11, 2010, 10:56:21 PM
Connecting any small scale electrical generator (SSEG), such as PV, wind, hydro or CHP, in parallel to the UK grid is governed by several interlocking pieces of legislation.

Engineering Recommendation G83/1-1 (referred to as G83 below) is the current set of rules that apply to the connection of SSEGs to the public electricity network.  It has been drawn up, and continues to be developed, by a working group of the Distribution Code Review Panel (DCRP) formed under the control of the Energy Networks Association (ENA), a body made up mostly of members of the Distribution Network Operators (DNOs).

G83 is an annex to the UK Distribution Code which, in turn, is developed under the auspices of the Electricity Safety, Quality and Continuity Regulations (ESQCRs) as enacted by parliament. Any changes made to G83 are required to be approved and promulgated by OFGEM, who are responsible for overseeing the whole regulatory process.

The ESQCRs state that all systems, with one exemption, can be connected to the grid only with the prior approval of the DNO. The exemption applies in the case of an SSEG up to 16A per phase and where that system complies with the requirements of both G83 and BS7671. In this case you can connect the system and then tell the DNO when it is complete.

DNOs are allowed to apply discretion regarding the 16A limit where, based upon their detailed local knowledge, they are happy that the network can cope with a higher figure and that no detrimental effects will result for neighbouring properties.

There are some circumstances where an SSEG connection under G83 may be denied by a DNO, such as multiple SSEGs connected on a single transformer. Prior discussion with the DNO is the only sure way to find out if this applies in a particular case.

If you are planning to install an SSEG larger than 16A per phase then you must contact your DNO before you install the system. They may require a network survey to be conducted (at your expense) before agreeing that you can go ahead.

The ESQCRs empower the DNO to disconnect any property from the grid if they are not happy that the installation complies with the regulations.

G83 covers both the type-testing of particular products, such as inverters, to ensure that these comply with the appropriate technical requirements and also to the complete installation of a SSEG. Type tests are usually arranged by product manufacturers and have to be carried out by suitably accredited test labs and these labs may be in-house (for the larger manufacturers) or separate commercial operations.

When you purchase an inverter you should make sure that you get a copy of the G83 test certificate from the supplier.  Some manufacturers have copies which can be downloaded from their websites.

Details of the type of tests covered by G83 can be gleaned from the Type Verification Test Sheet - see ref below.

When an SSEG is installed the electrician responsible must complete and sign a commissioning certificate to confirm that the complete system complies with G83. The system owner needs to keep a copy of this and a second copy must be sent to the DNO. The completed paperwork must be submitted to the DNO within 30 days of the system being commissioned.

Other countries have similar, but not identical, regulations to G83. Germany, for example, has DIN VDE 0126 and Australia has something called AS 4777.
Ireland have decided to make use of G83 rather than going to the trouble of developing their own separate regulations.

In recent years there has been an effort to bring about wider EU and global harmonisation in this area through CENELEC and IEC. The same UK engineers who have developed G83 have been in the working group to develop EN 50438. Not surprisingly, as the UK has taken the lead in this, it generally embodies all the same requirements as G83.

Refs:
DCRP Constitution - http://www.energynetworks.org/dcode/pdfs/GBDCRP%20Constitution%20and%20Standard%20Procedures%20October%202009.pdf
DNO Contact details - http://www.energynetworks.org/engineering/pdfs/DG/DistributorNetworkOperatorContactDetails_071114.pdf
Electrical Safety, Quality and Continuity Regulations 2002 - http://www.opsi.gov.uk/si/si2002/20022665.htm
ENA - www.energynetworks.org
Grid Code - http://www.nationalgrid.com/NR/rdonlyres/67374C36-1635-42E8-A2B8-B7B8B9AF2408/35187/Complete_I4GridCode.pdf
G83/1 Type Verification Test Sheet - http://2010.energynetworks.org/storage/engineering/ER_G3-1_Appendix_4.doc
International Harmonization of Islanding Prevention Requirements, Woyte et al, 2003,  http://www.kuleuven.be/ei/Public/publications/EIWP03-09.pdf
Technical Guide to the Connection of Generation to the Distribution Network - http://www.energynetworks.org/engineering/pdfs/DG/FES_00318_v040211.pdf
The Distribution Code of Great Britain - http://www.dcode.org.uk/
Western Power - Connection Considerations for Distributed Generation - http://www.westernpower.co.uk/getdoc/8269db62-16ed-4fe2-ae7f-82ae794aeece/Connection-Considerations-for-Distributed-Generati.aspx
Western Power - Connection Considerations for Small Scale Embedded Generators - http://www.westernpower.co.uk/getdoc/3d0c88f4-7010-44c6-aa7b-7b78c44af0ce/Connection_considerations_for_small_scale_embedded.aspx
Western Power - SSEG Installation Commissioning Confirmation - http://www.westernpower.co.uk/getdoc/26ee74bb-96be-48ca-b5a1-4bfe88eb4f51/Installation_Commissioning_Confirmation_Form.aspx

Copies of G83 are available for purchase from http://www.ena-eng.org/ENA-Docs/eadocs.asp?WCI=DocumentDetail&DocumentID=8016

[edit - made a sticky]


Title: Re: G83
Post by: guydewdney on January 11, 2010, 11:02:05 PM
I was going to give you a well deserved applaud for that, very concise, informative summary of the complexities of G83


but then you said "The ESQCRs empower the DNO" and that is just marketing speak twaddle - so you get a (wyleu style) smite instead ;) LOL


Title: Re: G83
Post by: Ted on January 11, 2010, 11:09:43 PM
Umm, it's not marketing twaddle - it is the use of the word in its correct sense. The power to do that is delegated to the DNOs.


Title: Re: G83
Post by: daftlad on January 11, 2010, 11:29:36 PM
I am very glad we have THE TED, he explains lots of complicated stuff in ways us daft people can understand.
cheers Ted.
ta ta


Title: Re: G83
Post by: Tigger on January 12, 2010, 09:19:18 AM
Ted,

I agree with you, it's the correct use of the word.  As a result of reading this, I felt empowered to applaud you  ;D
.


Title: Re: G83
Post by: northern installer on January 12, 2010, 09:21:13 AM
Ted,your endless research is rewarded with an applaud


Title: Re: G83
Post by: jotec on January 12, 2010, 09:28:29 AM
Many thanks, It is getting clearer as time goes by.
D cik


Title: Re: G83
Post by: StBarnabas on January 12, 2010, 10:58:01 AM

The ESQCRs state that all systems, with one exemption, can be connected to the grid only with the prior approval of the DNO. The exemption applies in the case of an SSEG up to 16A per phase and where that system complies with the requirements of both G83 and BS7671. In this case you can connect the system and then tell the DNO when it is complete.


Ted
one minor correction to this
http://2010.energynetworks.org/distributed-generation
On 4th August 2008, the Health & Safety Executive issued a Certificate of Exemption that effectively relaxes the timescales for notifying a DNO when comissioning Small Scale Embedded Generation (SSEG). The DNO must still be notified but in the case of SSEG this no longer needs to be before, or at the time of, comissioning. Notification must now be made within 28 days of comissioning.

Sean


Title: Re: G83
Post by: Ivan on February 01, 2010, 10:53:36 PM
Of course the consumers' rights outlined in St.B's documents are at odds with the DNO's right to refuse permission for G83-compliant systems below 3.6kW if they want to. I don't imagine it's ever happened, but I'd be peeved if I'd spent several thousand pounds to then find the DNO enforcing their rights.

Incidentally, does anyone know what level of PV or wind you're allowed to install in Europe under their equivalent of G83, before needing to seek DNO's permission?


Title: Re: G83
Post by: Mistertea on June 05, 2010, 03:18:36 PM
Ted's answer on 10.1.10 was very informative to me as a house builder with no electrical background One bit I need to clarify though. Ted says "There are some circumstances where an SSEG connection under G83 may be denied by a DNO, such as multiple SSEGs connected on a single transformer. Prior discussion with the DNO is the only sure way to find out if this applies in a particular case."
Does this refer to conection to the DNO transformer and therefore mean that if we are installing 1kwp pv systems on a street of 20 houses we should be talking to the dno first or is it the case that because all the properties are less than 3.6kw the house buyer will have no problem in getting a connection?


Title: Re: G83
Post by: guydewdney on June 05, 2010, 05:23:10 PM
Talk to the DNO first - definately. The spec basically says that you can connect, with their permission, and they won't check the install (as its too small to worry about)

But you can't guarantee a connection - imagine you wanted to install 20 houses all with 3.6kva gennies - the local transformer wouldn't handle it - and the 'last' few houses would get refused.

Go have a look at the transformer - if its huge and close, then you might be OK...


Title: Re: G83
Post by: Ted on June 06, 2010, 10:47:52 AM
Yes, as Guy says, you need to talk to the DNO first in these circumstances. They will be concerned about harmonic distortion as well as the total loading.

If this is a new build then there shouldn't be too much of a problem as usually the road will be fed from a 3 phase supply, with each house in a group of 3, on a separate phase. But in a rural area, with feeds from an overhead 11kV line, it could be quite different and until you talk to the DNO then you are not going to know.


Title: Re: G83
Post by: marshman on July 17, 2010, 09:38:58 AM
"The DNO must still be notified but in the case of SSEG this no longer needs to be before, or at the time of, comissioning. Notification must now be made within 28 days of comissioning."

Can anyone tell me who notifies the DNO. Is the installer, the owner, the supply company paying the FiTs, OFGEM when you register with them???

I have filled in the FiTs agreement, got my MCS certificate etc. even supplied my first quarters meter readings so can I assume my DNO knows about me?

I am a little bit wary at the moment as I have put in a complaint to EDF, my DNO?, about high mains voltage which they are investigating (swells up to 257V frequently - as seen on their monitoring equipment.) I sit right at the end of the line in a rural area and am the only feed off of a small 11kV transformer.

Thanks for any info

Roger


Title: Re: G83
Post by: Ted on July 17, 2010, 10:26:52 AM
I would expect the installer to do it.

Most DNOs have a copy of the required paperwork on their website so that you can see what info is required but, as the owner, you may not have all of that info to hand. The installer definitely should.


Title: Re: G83
Post by: JohnS on July 17, 2010, 11:58:34 AM

I am a little bit wary at the moment as I have put in a complaint to EDF, my DNO?, about high mains voltage which they are investigating (swells up to 257V frequently - as seen on their monitoring equipment.) I sit right at the end of the line in a rural area and am the only feed off of a small 11kV transformer.

Thanks for any info

Roger

The DNO should be able to change the tapping on the transformer to give a lower voltage.  Often the voltage was set at the top end of the range if a lot of electrical power was going to be used.  E.g milking machines at a farm.


Title: Re: G83
Post by: marshman on July 18, 2010, 12:33:55 PM
[
[/quote]

The DNO should be able to change the tapping on the transformer to give a lower voltage.  Often the voltage was set at the top end of the range if a lot of electrical power was going to be used.  E.g milking machines at a farm.

[/quote]
Yes they should, but they are reluctant to do so without lots of investigation. They have monitored one of the other phases and this is not as high. The EDF engineer that  fitted the logging/monitoring box was aware I was feeding back into the grid - he wondered where 10.5amps was coming from. But he said his boss has said allow up to another 4V on top of the upper limit (253V) to allow for the grid tied inverters!! He didn't think they had a requirement to keep to 253V if there was a generator feeding back !!!  He did admit that the whole issue of microgeneration was still evolving and that they as the DNO didn't really have much to do with it at the moment - but they were aware of it!!

Roger


Ted,

I will phone the installer on Monday and ask the question.

Thanks



Title: Re: G83
Post by: Philip R on November 19, 2010, 11:05:38 PM
Well done Ted,

You are very well informed and your articles concise, explicit and timely. You will get an applause mark from me.

Regards, Philip.


Title: Re: G83
Post by: Philip R on November 19, 2010, 11:23:23 PM
In reponse to Marshmans comments.

When you said the volts went upto 257V,
The system voltage you see is partly due to variances on the supergrid system. Yes, it swings about during the day as voltage gradients down a power line are used to shift real and reactive power.  Local variations should be partly compensated by tap changing or VAr control at the bulk supply point by NGC or DNO. Finally, your local 11kV/415 transformer should have either an off load tap changer or a link box with tappings above and below nominal values.


Title: Re: G83 - 1st G83 solar, 2nd G83 hydro allowed?
Post by: peterpiper on January 14, 2011, 12:39:33 PM
Whats the position if you have one system connected under G83 then want to add a second G83 of a different technology eg Hydro 1kW then Solar 3.6kW.

As I understand: Solar PV systems under 16A per phase (i.e under 3.68kWp) come under engineering recomendation G.83/1. Solar PV systems installed under G.83/1 can be installed without prior notice to the DNO, with the DNO being informed afterwards (within 30 days).

So the DNO will have been informed of the first installation, but it seems that DNO expects to be told after installing the second system. Is that the case or do the rules say anything different somewhere.

In our particular case we are fed overhead from a transformer 150m away, which also feeds one other house. It's fed single phase HV for about 1km. The transformer and HV line were installed 5 years ago, it's much larger than the old transformer, which was much further away and fed 5 properties, replaced due to low voltage issues.

SSO is Scottish Hydro, local MCS people say getting above 16A with them is hard.

At the moment we are deciding on PV system, may want to add hydro 500-1kW, later so what maximum PV size to stay G83?


Title: Re: G83
Post by: freddyuk on January 16, 2011, 12:42:17 PM
I had a conversation with a guy who just completed his PV course prior to his first qualifying installation.
I asked him about the G83 limit as I think it is 16 amps out of the inverter which should be the defining measurement although I would prefer the 4kw installed collector capacity. He started scratching his head as they had not really defined this but he did assure me that the accepted voltage should be based on 240 volts.
That is 3840 kw.



Title: Re: G83
Post by: Ted on January 16, 2011, 03:11:25 PM
"16 A per phase, single or multiple phase, 230/400 V ac"




Title: Re: G83 - 1st G83 solar, 2nd G83 hydro allowed?
Post by: GavinA on January 19, 2011, 12:21:26 AM
Whats the position if you have one system connected under G83 then want to add a second G83 of a different technology eg Hydro 1kW then Solar 3.6kW.

As I understand: Solar PV systems under 16A per phase (i.e under 3.68kWp) come under engineering recomendation G.83/1. Solar PV systems installed under G.83/1 can be installed without prior notice to the DNO, with the DNO being informed afterwards (within 30 days).

So the DNO will have been informed of the first installation, but it seems that DNO expects to be told after installing the second system. Is that the case or do the rules say anything different somewhere.

In our particular case we are fed overhead from a transformer 150m away, which also feeds one other house. It's fed single phase HV for about 1km. The transformer and HV line were installed 5 years ago, it's much larger than the old transformer, which was much further away and fed 5 properties, replaced due to low voltage issues.

SSO is Scottish Hydro, local MCS people say getting above 16A with them is hard.

At the moment we are deciding on PV system, may want to add hydro 500-1kW, later so what maximum PV size to stay G83?

I'll take this one...

the rules would seem to indicate that you need to notify the dno in advance and gain permission / check that the transformer can take it / pay for an upgrade if needed, but then still install to G83 standards on each sub 16amp microgenerator. At least in our experience with SSE (the scottish branch), though they absolutely insisted on us also installing a G59 control box between both g83 inverters and the grid connection as an additional control measure / safety net.

this was 6kW wind pre-existing plus 3kWp solar PV, so they may look more favourably on it if it's only a kW of hydro.

if that's clear as mud still I apologise, I gave up arguing and installed the extra control box as I couldn't find anyone who's role it was to act as an independent arbitrator between the DNO & us, so it seems the decision is based on the whim of the DNO in question rather than any actual guidance or legislation.


Title: Re: G83
Post by: jamesingram on July 19, 2011, 10:01:20 PM
G83/1-1 is ok for systems up to 3.68kW ( ok so this is inverter peak ac rating not peak panel size, just found out on DNO thread , good news for me )
I've heard 3.84kW mentioned ( 240Vac being used not 230Vac ) this seems wrong,
But I also heard G53/2 did really apply til >5kWp so creating a vague grey area.
Also due to inverter/system loss , systems around 3.69-4 kWp wouldn't exceed 16A so G83/1-1 may still apply ?

Anybody fancy helping the class div  , not done anything above 3.68kWp, so far so if client want 3.69-4kWp whats the score ?
If we use a 3600 inverter ,then its no problem , what about a 3800 or 4000,  wacko ,

cheers Jim


Title: Re: G83
Post by: jamesingram on July 19, 2011, 11:02:31 PM
This seem to answer my question a bit ,
"The definitions in G83 are clear that the G83 system includes all associated
equipment (clearly that would include inverters and protection) and
that the output is at 230/400V and 50Hz. Therefore the output of your
system should be after the energy used by the associated equipment,
not simply the output of the energy source (e.g. the solar panels).
We recommend that you quote the NET generation figure which
is the actual generation capability of the scheme after energy
use for inverters etc has been taken into account."
http://www.ce-electricuk.com/som_download.cfm?t=media:documentmedia&i=728&p=file

Any one got a reliable figure for PV system loss ?
sma design tool give approx 82% for therotically Pv yeald to power fed into grid
or approx. inverter efficency of 95% depending on inverter used .         PVGIS suggest total system losses 14%

so inverter of max power 3.8kW ac ( 3.8 x 0.95) would work out 3.61kW into grid , so g83/1-1 applies
do this make sense ? cable loss also to consider .


definition of TIC,  Total Installed Capacity and DNC,  Declared Net Capacity here http://www.ownergy.co.uk/library/gosple/F2RCAP1d.pdf





Title: Re: G83
Post by: BruceB on July 19, 2011, 11:32:27 PM
In that link, the reasoning/terminology in question and answer 11 is not quite right, but they do come to the right answer.  It is the output of the inverter that matters.  I have gone through it all in a post and discusion a month or 2 ago.

An inverter of maximum power output say 4kW can deliver 4kW assuming there are enough panels.  No efficiency calcs necessary.  If there are less panels than the inverter is capable of outputting then efficiency calculations are required to get the answer.

In a simple domestic PV set up then TIC and DNC are the same thing: the output of the inverter.  FIT band is decided by TIC.  DNO is generally interested in DNC.  DNC would be lower than TIC when there is some other plant drawing power from the generator, as an example external cooling systems.

The view offered by Ownergy in your link that TIC is the output of the panels  is wrong.

The 'grey area' between G83/1-1 Stage 1 and G59/2 is G83/1-1 Stage 2.  Have a look on the Energy Networks Association site to read about it.  I have done a few applications under that regime and it all works fine.  The one wrinkle now is that around me Western Power Distribution have started asking for the G83 parameters on inverters to be tweaked in that situation (over-frequency setting raised to 51.5Hz) or G59 standards applied, whereas a few months ago they were allowing standard G83 settings.

Regards
Bruce


Title: Re: G83
Post by: jamesingram on July 19, 2011, 11:35:39 PM
thanks again Bruce , got a link to your previous thread
cheers Jim


Title: Re: G83
Post by: BruceB on July 19, 2011, 11:46:23 PM
Here you go.  Quite a long thread.  If the link works then my long explanation starts towards the bottom of this page.
http://www.navitron.org.uk/forum/index.php/topic,13403.msg151372.html#msg151372


Title: Re: G83
Post by: EccentricAnomaly on July 19, 2011, 11:51:26 PM
I've heard 3.84kW mentioned ( 240Vac being used not 230Vac ) this seems wrong,

If the voltage actually is 240 V then that'd be OK as it's within (just on the edge of) the 16 A/phase limit. If it's 239 V then it'd be naughty at 16.0669... A.


Title: Re: G83
Post by: jamesingram on July 20, 2011, 04:14:53 PM
thanks Bruce , I'll try to digest it all.
Quick look , it seems strange that there's not clear guidance from Ofgem ; with higher effiency panels coming on the market , getting as close to 4kWp and more importantly the 16A limit ffor easy installation on to the grid , is surely in the interest of the FITS funded national PV project
Getting as big and cost efficient system on each household as poss. to maximise returns for all. ( including us the energy bill payers funding this FITs scheme)


Title: Re: G83
Post by: Ted on July 20, 2011, 05:25:34 PM
The ENA are discussing G83 changes. And the DTI PV install guide is going to be updated to version 3 with the intention of clarifying use of RCDs, frame earthing, TL inverters, etc.

But none of these things happen quickly.


Title: Re: G83
Post by: GavinA on July 21, 2011, 08:46:44 PM
thanks Bruce , I'll try to digest it all.
Quick look , it seems strange that there's not clear guidance from Ofgem ; with higher effiency panels coming on the market , getting as close to 4kWp and more importantly the 16A limit ffor easy installation on to the grid , is surely in the interest of the FITS funded national PV project
Getting as big and cost efficient system on each household as poss. to maximise returns for all. ( including us the energy bill payers funding this FITs scheme)

use a 4000TL, change the maximum output setting to 3680W, change the installer password to prevent the customer changing the settings back, make a clear note of this on the DNO notification form stating that the inverter output is limited to 3680W / 16amps AC.

Job done.

Biggest system we've installed this way is 4.5kWp DC, with the rating for both G83 and MCS/FIT purposes being the 3680W or 16amps.


Title: Re: G83
Post by: jamesingram on July 21, 2011, 08:59:31 PM
Fantastic , just what I was after ,  thanks Gavin



Title: Re: G83
Post by: jamesingram on July 21, 2011, 09:45:37 PM
Wondering what effect reducing the max. output setting on inverter would have on annual yeald , I presume reduce it some ( compared to leaving it a 4kw max AC output ), but at the same time allow larger systems to nick a bit more generation and FIT payment at the higher rate and stay in G83  
Do you think the extra panel costs would add up ??

Currently considering a 16 ,and now 18 after comments above, 240W panel system on a 4000TL  , two different pitch angles ( upper and lower roofs ) same origination hence the TL would make sense ? ( 8/8 or now 10/8 string split )
Sunny design showing 400kWh/year difference , but obviously this doesn't take into account the max. ac setting reduction to 3.68


Title: Re: G83
Post by: GavinA on July 21, 2011, 10:22:44 PM
you'd obviously lose some production at the top end, but in peak sunlight the panels will be operating at higher temperatures, so there'd be something like 15% reduction in output from this, plus maybe 5-6% inverter losses, so it'd mostly be operating at around 3.6-3.8kW at the top end anyway other than for brief periods.


Title: Re: G83
Post by: EccentricAnomaly on July 21, 2011, 11:23:41 PM
Also the different pitch angles would slightly reduce the peak possible hence reduce the losses due to the limit.


Title: Re: G83
Post by: brackwell on July 22, 2011, 10:32:05 AM
jamesingram,

I am going to fit 5Kwp with a sma 4000TL and have been researching/monitoring the output of http://pvoutput.org/intraday.jsp?id=2476&sid=1872&t=3&gs=0&da=1&s=1 who is close to me. My conclusion is the advantage way way outweighs the peak chopping.

Ken