DNO wants G59 connection for 3kVA solar due to 6kVA wind... anyone?

[GavinA]

I'm having a bit of a headache with a DNO for a job where we're wanting to install 3kVA solar PV (grid connected) on top of an existing 6kVA wind turbine, and would appreciate any input from anyone who's been in a similar situation.

Basically we checked with the DNO that the substation could handle the additional 3kVA generation, and the DNO came back and said yes, no problem, but then added that because the total generating capacity is above 16amps (single phase) that we have to install the PV inverter to comply with G59 standards, and also (for some reason) they now want us to convert the existing wind installation to 59 settings as well.

Now, my reading of the ENA guidance is that for multiple installations, as long as there's sufficient headroom at the substation, and the individual technology is under 16 amps (single phase), then for PV it should still be installed to G83 standards as set out in the quotes from the ENA guidance below.

***
>>>G59.2, Page 22

"If you are installing multiple generating units that fall under G83/1-1 refer to 'Getting Connected: SSEG G83/1-1 stage 2"

>>>G83/1-1 Stage 2, page 21

Your generating unit falls under G83/1-1 if:

* It meets the size definition of SSEG      At 3kVA, the PV generating unit falls under 16 amps
* The generation type has a type testing appendix in G83/1-1 (listed above)      PV is listed
* The generating unit is approved - ie it has been tested in accordance with the appropriate appendix and has passed the tests     the inverter will have g83 certification
* The generating unit is installed in accordance with with G83/1-1    which it will be

***
Does anyone have any experience of similar situations, and if so has the PV been installed to G83 or G59 standards, and is this what the DNO has asked for?

also, does anyone know of it's possible to reprogramme a sunny boy to G59 standards? I am trying other avenues to find this out, but if anyone's done it then I'd at least know it was possible without needing to spend serious amounts of extra money buying something (eg) to put in front of the inverter to convert it to G59.

any advice appreciated.

[guydewdney]

any chance of three phase being installed? then you are still on 16 PER PHASE....

[Ivan]

I've spoken at length with DNOs, and my understanding is that although they have the right to demand G59, most will accept up to 17kW per phase under G83 if the lines are sufficiently rated to take the power. There is an official delineation at this power (is it where you need to have HH metering?).

[GavinA]

any chance of three phase being installed? then you are still on 16 PER PHASE....

somewhere between slim and none I'd think as it's down a long track with the nearest 3 phase probably 2-300 metres away.

[GavinA]

I've spoken at length with DNOs, and my understanding is that although they have the right to demand G59, most will accept up to 17kW per phase under G83 if the lines are sufficiently rated to take the power. There is an official delineation at this power (is it where you need to have HH metering?).

hmm... I might try begging then.

There is a lot of largescale wind in the area, so it's possible that they've made a company policy to use g59 as much as possible, but they've not said that, merely referred to the ENA guidance and said that under this I need to install to G59.

what's HH metering btw?

[fred bloggs]

GavinA

HH is half hourly metering which means that your electricity consumption is monitored and charged every half hour!!!, and is a whole different ball game to normal domestic type metering, your have to have a meter operator as well as an energy supplier and it can get very complicated. Normally you have to have HH metering above 100Amps per phase which works out at 23KVA or 18.4KW at 0.8pf.

Best Regards

Fred

[GavinA]

ah ok, cheers fred, I've not got up that far on anything yet.

I think it seems like we / the customer's going to just have to bite the bullet and buy the g59 device to stick in front of all the inverters... hopefully this'll not scupper the entire job. 

thanks btw to Ivan & guy for their input, I reckon this probably is one of those situation where it may make sense for them to ask for G59 as it probably is quite a long way from the substation, with quite a lot of largescale wind close by, and apparently the G83 bit on the existing inverters does drop out fairly frequently when the wind's gusting, so I can understand why the DNO would have decided to ask for G59, they just explained their reasoning a bit oddly by referencing the guidance rather than this installations specific circumstances.

[GavinA]

this is still ongoing fwiw, install is done and locked off until the dno makes a final decision - I think I've thrown the cat among the pigeons up there by pointing out the major flaws in their interpretation of the guidance - ie attempting to shoehorn G59 protection settions into the phrase 'commissioning requirements' which covers the entire output, rather than the phrase 'protection requirements' which is specified only to cover each generating unit individually.

I'll feed back in due course once they've had their discussions and got back to me, but after severely interogating the guidance I'm pretty clear that the guidance itself says G83 protection settings should be used in this situation, and the DNO weren't citing any special circumstances, just pointing me at the ENA guidance.

[ecogen]

G59-2 came into force on the 1st August and replaces G59-1 and it's associated ETR113 together with G75-1.
Opinion from an engineering perspective? Structured with the aid of speech impaired WIBBLE. As a comparison imagine G83 ranges from a hamster [6] wheel to a moped and G59-2 ranges from a 125 to a space rocket and beyond. Some common sense has been applied, like not needing a license for the 125.
G83 1-1 will now need to be amended where reference to G59-1 and ETR113 is given.
Unfortunately it also adds some clarity to the until now "grey area" between G83-1-1 over 16A phase connections and the old 1995 G59-1.
This affects your situation and is chargeable should the DNO decide to. So don't upset them with strongly worded letters based on "Guidance" info. It's true that some DNO staff are a bit dim (I'm being polite here) in dealing with connection issues. However, the smart ones already have enough work on their plate and don't take kindly to encounters with inexperience, and err "me". The ENA guidance docs are very informative and a great help, but they are no substitute for the actual ER docs.
That said I will try to explain your situation as I read it.
As you wish to install an additional SSEG at the same site, then the wind turbine is the problem. The additional 3kW Solar installation is not G83 Stage 2 because the existing wind turbine is over 16A phase.
A SSEG can only be considered G83 Approved for connection if it satisfies the test conditions in the appropriate annex. In the event that there is no annex (eg Wind Annex E Under construction) then the matter should be discussed with the DNO, using existing annexes as guidance. Namely using an inverter as the interface, then Annex C can be applied [1]. However your wind turbine is over 16A phase and so the DNO has the choice of which ER it uses for a SSEG without an annex or one over 16A phase[2] [3].
Now we have to look at G59-2.
Section 6 Identifies what falls within the scope of G83 or requires G59-2.
6.1.6 Amalgamations and additions.
The application process and commissioning requirements should be based on Power Station capacity. ie all individual units added together that are installed in any one location. Protection requirements for each unit should be based on the table in 6.1.2. This part is good news as the PV is G83 approved / compliant, so according to the table in 6.1.2. Protection requirements for the PV are to meet G83. However the wind turbine being greater than 16A phase requires protection settings to comply with the requirements of G59-2, type verified protection equipment accepted [4]. Witness testing at the discretion of the DNO.
If DNO accepts your wind Inverter as being "type approved" then changing the protection settings in writing to those listed in table 10.5.7.1 is possible and they then confirm the new settings [5] or they should request an individual supervision relay like that referred to in the first post. Fact being that the inverter is not strictly covered by the new G59-2 type testing [4].
With regard to using G83 for connections over 16A phase, G59-2 mentions JUST over [7]. Section 6.1.4 includes a new type verification and connection simplification up to 17kW single phase. In effect G83 with G59 settings [4].
On top of all this are the site specific conditions, Voltage rise, unbalance ect.
Good luck.



[1] G83. Annex C PV. Note 3. Other annexes containing inverter connected equipment may make reference to the requirements specified in this annex.
[2] G83. 2. Scope. Note 2. As the SSEG has a rating greater than 16A phase the DNO may choose to use G83 if it is considered to be more appropriate than G59-1 (G59-2). For example the connection of a 5kVA PV array or 10kVA wind turbine.
[3] G83. 2. Scope. As the SSEG has a rating greater than 16A phase the reader is referred to ER G59-1 and ETR 113 (G59-2).
[4] G59-2. Appendix A 13.7. Available free from ENA.
[5] G59-2. 10.5.9. Protection settings in 10.5.7.1 should be used. In exceptional circumstances Generators (You) have the option to agree alternative settings. (This is more a president to the fact that protection settings can be changed)
[6] Genetically modified Hamster fed on amphetamine.
[7] G59-2. 13.7.1. Note1.

[BruceB]

Given G83/1 costs an arm and a leg to buy a copy of, you might like to know that G59-2 appears to be downloadable for free:
http://2010.energynetworks.org/storage/ENA_ER_G59_Issue_2_2010.pdf

[GavinA]

egogen - you're missing a vital point, namely that the wind turbine is already installed and operating, and has been for 18 months with full DNO approval, so they can't really insist on G59 for the wind turbine at this stage, it's the PV they're insisting on G59 for, although they have also asked that the wind be covered by it as well.

as for the rest... I've just typed in G59, wind and solar into google, and this thread comes top, so I'm not really sure I want to comment further, oither than to say that the DNO were trying to make out that the G59 protection settings requirement was covered in the commissioning section rather than the 'protection settings' section. I've pointed out the rather obvious flaw to that interpretation of the guidance, and the DNO people (who've been pretty helpful through this, and I think I've managed to maintain an ok relationship with) have now referred this up, so hopefully they'll now alter their policy.

[ecogen]

egogen - you're missing a vital point

Err... you installed the extra PV without referring to G83, G59 and the Distribution Code?

You installed the extra PV without a connection agreement?

You have a headache?

My ego has just eaten a whole packet of custard creams and is not looking very well...... I'll clean the mess up later.

In my last post I referred to the wind turbine as EXISTING. I then referred to parts of G83/1-1 that apply to it. The reason being to show that it does not fit well with using Stage 2 to connect the additional PV. Because 1). The definition of a SSEG [1] used in 5 Requirements. 5.1.2 Stage 2 Connection (multiple / planned install) and 2). It would be G59 if not for the DNO considering G83 more appropriate, for a SINGLE unit. [2] [3].

Excerpt from the Distribution Code.

(DPC7.1.3 For the avoidance of doubt a user who has installed a Generation Set in accordance with Item 13 DGD Annex 1 Engineering Recommendation G83/1-1 ("Recommendations For The Connection Of Small-Scale Embedded Generators (Up To 16 A Per Phase) in Parallel With Public Low-Voltage Distribution Networks") and where this is (are) their ONLY Generation Set(s), and which has been installed, commissioned and operated in accordance with Annex 1, Item 13, that User shall not be required to comply with the requirements of DPC7 in respect of that (those) Generation Set.

DPC7.2.1 Embedded Generators connected to the DNO’s Distribution System WILL comply with the requirements of Item 3, DGD Annex 1 Engineering Recommendation G59/2, "Recommendation for the connection of generating plant to the distribution systems of licensed distribution network operators". )

I see this as generation installed using G83 (Stage 1) or sets (Stage 2) does NOT have to meet the requirements of G59.

However this is applicable to the users ONLY generation set(s). If additional generation is to be added then it WILL have to comply with G59.

Therefore, 6 Connections 6.1.6 Amalgamations and additions needs to be considered. I repeat that the solar PV does NOT require G59 protection settings.

A contactor and supervisory relay installed and tested would comply with the requirements of 12.2.5.http://www.g59-test.co.uk/page5.html This will require A 13.3 commissioning tests. All together £2k of pain.

In my last post I was trying to find a way within the documents to save the need for this. Refer to 12.2.2 and consider trying to persuade the DNO to accept the wind turbine as "type approved generating plant", even though it is G83 approved and not G59, by changing the protection settings and adding comment on the inverters type verification test sheet. You then self certify that "type approved generation plant" is installed and complies 12.2.4 c.

With regard to G83 / G59 protection settings there is no Over Voltage difference, 1.8 Under Volt difference, 0.5 Hz Under difference and 1 Hz Over difference.

Trip times depend on the type of inverter, but if generic then G83 is quicker to trip.

It seems obvious that the G83 protection settings in the individual inverters are more than adequate to safeguard 9kVA of connected generation.
Common sense would be to choose appropriate settings that keep within the limits and achieve stable system operation at that location.
I have tried to get as close as possible to this end by using the ER docs quoting chapter and verse. If G83 had been extended to 17kW 1 ph. and 50kW 3 ph. then this level of absurd complexity would be avoided.



[1] G83 1-1. 4 Definitions. SSEG. A source of electricity rated up to and including 16A phase single or multi 230/400V.

[2] G83. 2. Scope. Note 2. As the SSEG has a rating greater than 16A phase the DNO may choose to use G83 if it is considered to be more appropriate than G59-1 (G59-2). For example the connection of a 5kVA PV array or 10kVA wind turbine.

[3] G83. 2. Scope. As the SSEG has a rating greater than 16A phase the reader is referred to ER G59-1 and ETR 113 (G59-2).

[GavinA]

firstly, both the customer and DNO have been kept fully informed at all stages, way above anything that's actually required, we have a connection agreement with the DNO for connection under G59 protection settings, but being as we do not believe this is necessary according to the guidance, with both of their consent, the installation has been undertaken but is currently locked off until this situation is resolved. When this is resolved it will either be commissioned as G83, or have a G59 compliant control unit fitted in front of both the wind and PV units if this is what the DNO require. As this is a £2k additional cost, we opted to wait until the DNO was in a position to give us a definitive answer, being as they now appear to be very unsure of their position and have referred this up the line for clarification. We would have given the DNO more time, but the installation was only confirmed with a couple of weeks notice as an additional installation to one we were already undertaking in the area so we didn't have that luxury (and contacted the DNO the day the installation was confirmed... so could you please leave aside any insinuations of unprofessionalism, unless you have any particularly pertinent comments on precisely how you'd have handled this any better. thanks.

secondly, you appear to be agreeing with me that the PV should not need to be connected to G59 settings, but it's a bit hard to tell. I've probably not helped the situation though by not updating this thread, as I've progressed my understanding of the situation and the DNO's position somewhat since the earlier postings.

anyway, to cut a long story slightly less long, you're right, it has boiled down to the interpretation of this paragraph in section 6 of G59/1 issue 2.

ref page 19 Section 6  para 6.1.6          Amalgamations and additions
                                                        The application process and commissioning requirements should be based on Power station
                                                        capacity (i.e. the aggregate capacity of all the Generating Units to be installed in any one installation).
                                                        The protection requirements for each Generating Unit should be based on the table in section 6.1.2.

The DNO was trying to say that the phrase 'commissioning requirements' in the first sentence dictated that the protection settings should be based on the total power station capacity and therefore must be G59 protection settings. I've pointed out that the protection settings would much more logically fall under the 'protection requirements' section of the second sentence, and therefore be related to each generating unit rather than the total power station capacity. If the protection requirements section doesn't encompass the protection settings requirements, then IMO it would make that paragraph fairly redundant, and commissioning requirements would logically refer to whether the DNO is required / can request to be present to witness the commissioning tests or not, rather than the actual protection settings.

Personally I'd still contend that this situation should have remained under G83/1-2 throughout, being as the DNO has already agreed to the wind being installed to G83 settings, so I don't see why it should afterwards be treated any differently to a standard type tested technology, but either way it seems clear that the PV should be installed to G83 protection settings.

re the wind turbine, I think possibly that technically the DNO could be able to alter their position regarding G83 vs G59 settings for the wind  (if the application isn't seen as a G83/1-2 application) as the guidance says these settings are discretionary, but give no indication of whether or not the DNO can then alter their initial decision on this. IMO there would be no justification for the DNO to change their mind on this, but I accept that it may well be within their power to do so, and that I'm basically relying on their goodwill to not insist on this change.

anyway, thanks for taking an interest, I'll be sure to post up the DNO's decision as and when I get it for information purposes.