DNOs and G83 limit

[solarfred]

Do you think DNO's could insist on only allowing inverters that are 16 amps limited by the manufacturer being installed into G83/1 installations? That solves the issue for UK Networks and I wonder if all DNO's might concur. That would not require a change in regulations as it is already a requirement that output is maxed at 16 amps. It does not resolve the disparity in voltage calculations though.

 

[Energetic]

Our DNO has, very sensibly, temporarily upped their limit to 17A per phase for G83 for 1 year. This means we can install a 4kw system on a 4000TL and still comply. This also means that national companies quoting here are telling customers they can't have an array above 3.6, which is nice...

 

[BruceB]

Which DNO?
And do you have a link?
Regards
Bruce

 

[solarfred]

Ted knows about these things Quote "G83 is quite definitely 16A at 230V for single phase. There is no guidance on how that is to be interpreted at different voltages.

Apparently discussion of G83 is on the agenda for the next meetings of the DCRP - a meeting of all DNOs under the auspices of the ENA. But I am informed that any decision on changes to G83 will take months to come into effect. The last update, from G83/1 to G83/1-1, took about 12 months." unquote.
So unless the DNO has changed the G83/1 regulation how can they do this?

 

[edexlab]

My understanding is that the DNOs have decided or been advised that they can allow upto 17kWp on a single phase under G83 if they want. I was chatting with our DNO Western Power about fitting 10kWp Wind and 10kWp of PV at my place and he told me about the 17kWp allowance on single phase, I don't want to have to pay to get 3 phase if I can avoid it. They tell me that they get so many conflicting memos about SSEG that it's a minefield for them to process. They are crying out for a policy that they can work to, I think the ENO&Ofgem need to pull their fingers out.

I think that this will depend a lot on your location and what the grid infrastructure is like, I've asked about the possibility of this figure of 17kw on a single phase and was told very unlikely in my area as the grid runs from 132kv straight to 11kv (its a fairly rural area) and Dno's have less opportunity to control voltage rises than with 132kv to 33kv to 11kv systems where apparently its less of a problem.

 

[wozzit99]

Posted on another forum

Hi

This is an email I received from Central Networks dated the 25th March.

Central networks comments are given in blue.

Hope this helps.



"So that I have definitely got this right could you confirm the following"



1. g83 goes up to 3.68kw after which g59 protection settings becomes the standard.

The standard G83 limit is 16A per phase (i.e. 3.68kW single phase or 11kW three-phase). For a single SSEG installation, this can be connected and then you can inform us later, providing all the commissioning documents etc to register for FIT. The standard G83 compliant inverter is acceptable (with upper frequency set to 50.5Hz). For connections >16A/phase, there has been a relaxation in the rules as given below.

2. It is possible to install up to 17kw on a single phase or 17kw per phase on a 3 phase system so long as the protection settings in the inverter are based around the g59 standard therefore negating the use of g59 relays ( this is depending on whether the line can take it )

We will accept a G83 1/1 type connection for a single SSEG installation, provided the inverters used are type-verified, and the capacity is no greater than 17kW single phase, or 50kW three-phase. You must submit an application form first (Appendix 2 of G83/1) to gain consent for connection, or to get costs for any reinforcement that maybe required. A G83 compliant inverter could be used, provided the upper frequency limit is set to 51.5Hz, or a G59/2 relay.

3. I have been quoting for a job where the customer requires approx 9.6kwp on a single phase supply. The intended design is to use 3 separate g83 inverters ,sma 3300 which as far as I am a where are configured with the g83 protection settings. Is it ok to use these inverters with the g83 settings as they individually are less than the 3.68kw limit ? The problem is I can't find a single inverter to use on a single phase which has the g59 protection settings and I don't want to get into the realm of g59 relays.

As above, the G83 protection should be set to 51..5Hz on the upper frequency

 

[wozzit99]

Looking at the protection settings on sma inverters they are set to the country relevent settings and they can not be altered.

How do you change the upper frequency to 51.5hz on a g83 type inverter?


Wozzit

 

[edexlab]

Looking at the protection settings on sma inverters they are set to the country relevent settings and they can not be altered.

How do you change the upper frequency to 51.5hz on a g83 type inverter?


Wozzit

I think it can be done using a communication device and with an authorisation code from SMA

 

[SolarCity]

Correct me if I'm wrong, but aren't the standards for G83 inverter a little more strict than a G59 relay needs to be?

 

[BruceB]

Yes, in terms of over-frequency, the G83 limit for GB is 50.5Hz and 0.5s, so I do not understand why Central Networks would say change the setting to 51.5Hz, as it is already within the G59 figure.

Regards
Bruce

 

[wozzit99]

Just a thought,

G83 over freq setting maybe in the range of G59 setting but it is also a full 1Hz below the reccomended limit. So nuisance tripping on larger systems might cause problems with the dno, thats why G59 settings are more forgiving. It does'nt explain why only the frequency limit has to be altered and not the rest of the parameters.

 

[BruceB]

I think you may be right there. Here is a G59 extract:



and also explains perhaps why sma went to the trouble of certifying their tripower range to the g59 standard in Feb this year

Regards
Bruce

 

[wozzit99]

Thanks Bruce

Is it only the tripower range of inverters which are accredited with g59?

 

[BruceB]

Do not know for sure, but just having checked their website for the 3000TL/4000TL/5000TL they only have G83/1 certification on the english page

 

[SolarCity]

Tripower inverters are accredited with G59? Are you sure?

 

[BruceB]

Yes
http://download.sma.de/smaprosa/dateien/1807/G592_STP8-17TL-10-ZEN110610.pdf

 

[claypole]

I was in contact with SMA to query aspects of the 4000TL, and specifically to see if it could be restricted to 16A output. I have copied below a reply I received asking if G59/2 certification would be useful? As a consumer, and having now completed my install, it's clearly of no concern to me but you might like to voice your opinion to the contact details below if you feel that certification would be helpful.

Dear Mr. S....,

currently we are discussing, if it is more usefull to have the G59/2 certificate for all inverters with a AC-current > 16 A. As I understand the regulations it is possible to use Generating Units > 16 A per phase and ≤ 50 KW 3 phase which must be G59/2 compliant. A type verified protection equipment is accepted.
So, would it be more helpful that you have the G59/2 certificate for that inverter ?


mit freundlichen Grüßen
Yours sincerely
SMA Solar Technology AG
i. A. Bernd Krah

Technical Support Medium Power Solutions
Sonnenallee 1
34266 Niestetal
Germany
Tel.: +49 561 9522-3314
Mobil: +49 151 54345943
Fax +49 561 9522-4080
E-mail: [email protected]

 

[Matt_M]

I had a chat with a chap from CE Electric, at the Yorkshire and Humber Microgeneration Project conference yesterday, and he confirmed they use the inverter output for the rating.

I also got it in writing.

 

[daytona600]

bit of confusion lately from board to board
some allow 16amp plus , some stick are rigid at 16amps output
two options
decrease dc Kwp of the system to approx 3.68kwp one less panel or 5/10wp decrease per panel
fit new 2011 sma sunny boys with limited 16amps output , bit of a waste of clients dc kwp output on sunny days
16amps on three phase generally not a problem eg with sma 10kwp STP10,000TL inverters

never had a answer from a dno yet about the answer if you fit a 4kwp dual-axis tracker
increase output by 30-45% compared to fixed systems
with high yield solarworld/sanyo with high effciency sma TL inverter

 

[Worcester]

fit new 2011 sma sunny boys with limited 16amps output

Looking at the current spec sheets where can I find that?

I have a west facing roof which we are looking at using the SMA SB3800 on, and I am looking for the maximum rating so that we can do it without needing to do a pre-install application. (3.68 kw) Only other inverter I can find maximum continuous rated at 16A / 3.68kW is the Diehl Ako 4300S

 

[officerdibble]

It is quite easy to install 4kWp installations and get within even the strictest DNO requirements, you know, the mad ones stating 3.68kW. Always state on the G83 form that the maximum generation ability is not greater than 16A.

This can be verified on the following basis.
Maximum DC generation capacity is 4kWp
Efficiency of inverter eg 95 %
Supply voltage = 243V

Make the calculation and the maximum generation capacity of the SSEG is (4000x0.95)/243 = 15.638A

Shimples Eek!

 

[TedM]

G83 16A limit is based on 230V and that figure should be used in the calculation.

 

[Worcester]

@officedibble,

Can't do that our certification is too important to us!

Either less panels, or the inverter has to be limited and since it faces west, I'm loath to reduce the number of panels for an artificial reason.

Found the inverter anyway, its the SMA SB3800V (the V is the important bit) it has a continous rating of 16A, specially made forthe UK market, so it complies with the GB83 limit, and the system output is within the parameters of the inverter.

 

[officerdibble]

G83 16A limit is based on 230V and that figure should be used in the calculation.

An interesting reply, please direct me to the specific paragraph which makes this directive. I possess G83 I will have another look at it.

Whether or not G83 states 230V the facts are quite clear, the mathematics speak for its self. Is this an arbitrary figure or is it backed by a clear calculable physical facts. 16A at 230V is fine, does G83 refer to the maximum current at 240V. Simple answer - NO.

 

[TedM]

The Electricity Safety, Quality and Continuity Regulations 2002 - The Electricity Safety, Quality and Continuity Regulations 2002

Parallel operation
22 (2) (a) the source of energy does not produce an electrical output exceeding 16 amperes per phase at low voltage;

Declaration of phases, frequency and voltage at supply terminals
27 (2) Unless otherwise agreed in writing between the distributor, the supplier and the consumer (and if necessary between the distributor and any other distributor likely to be affected) the frequency declared pursuant to paragraph (1) shall be 50 hertz and the voltage declared in respect of a low voltage supply shall be 230 volts between the phase and neutral conductors at the supply terminals.

http://energynetworks.squarespace.com/storage/DGCG G83 S1 Nov2010.pdf

SSEG is defined as

a source of electrical energy rated up to and including 16 A per phase, single or multiple phase, 230/400 V ac.

ER G83 is just another document that embodies and expands on these regulations.

 

[Graeme Harrold]

SP Energy Networks reqiuire G83/1-1 Ap2 in advance for systems exceeding the 3.6KW. Im fitting a 3.9KW system and will have to ensure my SMA inverter is reset to to G59 limits - 51.5Hz for 0.5 sec. If this is confirmed there is no need for a site visit or the associated relays.

My contact was a Mr Oldfield and was extremely helpful.

 

[Worcester]

@ Graeme Harrold

If the inverter is limited to 16A / 3.68 kW no need for an App2. Only inverters I'm aware of (so far ..) that meet this are Diehl Ako 4300S and the SMA SB3800V (Note the V)

Only problem with the SB3800V is single MPP Tracker, DA quite old tech.

We have a west facing install 3.99kWp that will never achieve 3.99. Western Power Distribution, nee Central Networks, OK with App3 if use an Inverter of that type, else must be App2.

 

[solarfred]

K-Mate HESI3800GT is limited to 16 amps. G83 certificate. Single tracker with two inputs. No fan to burn out as it is a heatsink version.

 

[avonsolarltd]

I have just installed 3.77kw on my roof as after speaking to my DNO Western power, all they kept saying was 16 A. I quizzed them about the supply voltage they said it had to be worked out using 230volt. My incoming mains is 236volts which I pointed out and they kept saying 16amps.
They really don't have a clue there needs to be something put in place asap. Lets hope 1 of them reads this.

 

[officerdibble]

230V is a nominal value, current is totally dependant upon actual voltage levels, therefore you cannot state 16A max and insist that it is worked out on 230V as the actual value will be different. G83 states maximum 16A. The DNO's actually have the discretion to connect up to 20A on G83 anyway. In most cases they will allow 4kWp systems. This is such a problem for the industry that I understand it is on the agenda for the next ENA meeting of DNO's.

Lets be clear about this, the only stated maximum G83 states is 16A it does not state max size in kW's. ENA created this problem it's time they put it right.