G83 - 6kW limit

[ecogen]

From some of the comments made about ER G83 it appears that many see it as as another piece of government bureaucracy infringing on their "right" to do as they see fit with "their" mains supply. If I want to connect more than the 16A a phase without the agreement of the DNO then why shouldn't I? I have a 60, 80, 100 amp fuse at the supply terminal. Where's the problem? Ministers and Civil servants who know FA telling us what we can and can't do! Oh dear, maybe I shouldn't have written this...... I'm beginning to believe it... YES...YES... I can...I can See the light!

Some time later, medication and a blown light bulb...
How many of us stop for a moment to look at the bigger picture? Consider how lucky we are to have a technical document like G83 and the legal framework in place to Force a DNO to accept a SSEG connection. G83 deserves better, a lot better. Just think what position would we be in without it?
Only a few years ago we had G77 for inverters, this was hard fought for, far from perfect and not in force for long.
Before this G59 ruled. Formal application which is chargeable together with witness testing which is also chargeable. The cost of this stopped the overwhelming majority of small schemes from progressing further than an idea.
Distributed generation especially micro has changed a lot over the last 10 years, DNO's are having to adapt to accommodate these changes and the associated costs. It is not difficult to understand why, relatively few people in these large organisations fully understand what is required of them. Training schools now teach DNO engineers the requirements of G83, for example the WPD school in Taunton. http://www.sei-energy.co.uk/Project_View?pid=28

There are many different connection situations that G83 needs to accommodate. Below is an example using data from an actual PV installation.
 

Rated capacity 2900W PV. DC.

AC output on a summer day. 250V. 10.2A  2555W.
Now consider the same location with 3.8kW PV installed. 16A output and low consumer demand.
What is the likelihood of voltage rise in excess of ESQCR limit?


[Firstly refer to ERG831/1.]
2. Scope. Connection Agreements are a legal document  supporting SSEG connection and are considered out of scope of G83 doc.
5.1 Connection Procedure.
The DNO may NOT refuse to accept connection providing compliance with ESQCR 22. (We will consider the installation complies)
Under terms of ESQCR 26 the DNO may require a SSEG to be disconnected if it interferes with the quality of supply to others.

[Secondly refer to ESQCR.]
ESQCR 27 Declaration of phases, frequency and voltage at supply terminals
(6) Every distributor shall ensure that, save in exceptional circumstances, the characteristics of the supplies to consumer's installations connected to his network comply with the declarations made under paragraph (1).

(1) Before commencing a supply to a consumer's installation, or when the existing supply characteristics have been modified, the supplier shall ascertain from the distributor and then declare to the consumer -
(a) the number of phases;
(b) the frequency; and
(c) the voltage,
at which it is proposed to supply electricity and the extent of the permitted variations thereto.

(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.
(3) For the purposes of this regulation, unless otherwise agreed in writing by those persons specified in paragraph (2), the permitted variations are -
(a) a variation not exceeding 1 per cent above or below the declared frequency;
(b) in the case of a low voltage supply, a variation not exceeding 10 per cent above or 6 per cent below the declared voltage at the declared frequency;


[Lets now look for guidance on the above ESQCR SI. This is Law and as so the final interpretation is a matter for the courts.]
Following taken from DTI Engineering Inspectorate. Guidance on ESQCR.
27 (2) Distributors should note that the declared values and tolerances are an absolute requirement, and any variation beyond the voltage limits (apart from exceptional circumstances) without the agreement of the consumer would be treated by DTI as a breach of this regulation.
26 (1)This regulation permits distributors to challenge consumers in circumstances where their installations are unsafe or are causing unacceptable electrical interference on the distributors network. Duty holders should note that the provisions of this regulation may be applied to consumers installations and to other installations or networks.


The ampere limit before DNO involvement is in part, such that the DNO's stay within Law. Remember that if your under 16A phase sseg causes a problem, ESQCR gives the DNO power to act, even though you were within the recommendation to connect.
Already been said, anything over 16A a phase is treated as a 5.1.2 stage 2 connection. Discuss the project with DNO at earliest opportunity, an application form found in appendix 2 should be submitted. No hard questions to answer unless you have difficulty in spelling your name. A site layout plan and a copy of the circuit diagram needs to accompany the form. The DNO has a section to say yes/no for permission and if no comment on the reason.

G83 1/1. is the self installers friend. MCS to qualify for FIT is your enemy.

[Ivan]

I'm not against G83, however, in an age of harmonisation, it would have made a lot of sense to harmonise this document with the European equivalent (not sure what that's called - is it ISOxxxxxx?). It's especially restrictive, as it costs around £15-20k to test a product to G83, and few manufacturers both, considering how small the UK market is - so it helps to reduce competition, and increase prices for the UK.

I do think that G83 should allow up to 6kW by default. The DNO is notified when an SSEG is implemented, so they can keep up with the loadings. If the network isn't capable of supporting the number of people exporting, then the DNO has plenty of time to upgrade the network. Often perceived problems evaporate when an organisation given the power to object is given the duty of rectification. Presumably any problem caused by too many people feeding 6kW into the grid is the same as too many people drawing 6kW from the grid. My 100A fuse allows me to draw up to 24kW. If 6kW is a problem, then we should downgrade 100A fuses to 25A.

[baker]

 Hi
 i have a 3 phase supply
 what is the max a can feed into grid
 with solar pv councl has on problem  with install on rear roof
 if a fit a sma inverter and chineese panels would i get fits if comm by mcs installer
what are the chineese panels like?
can you recommend any or system
 
   

[ecogen]

Ivan,
G83 1/1 is in effect EN 50438 which in some countries may be applied to generators with higher ratings than 16A phase. These countries are listed in Annex E. Whenever the scope is extended to equipment rated greater than 16 A per phase additional standards are applicable.
It costs to type test any notifiable product to comply with EU Directives. Our old friend the circular saw for eg.
The only extra test requirements needed to satisfy G83 is the interface protection, which has to meet the requirements of IEC 60255-5, Short circuit contribution IEC 60909 and DC injection.
As far as competition and G83, the document and EU Directives set a level playing field for all.
The DNO having to upgrade the network immediately a 6kW sseg connection notification is given is unworkable. They are struggling to maintain capacity as it is. Generators in parallel are used to support local networks where the HV conductors are too hot, until such time reinforcement can be implemented. This ensures that without unacceptable voltage drop, you can run your Air conditioners, splash about in the Bubble tub, boil your kettle when the soaps end and keep a skunk in a cupboard.
"Feeding and drawing" are not the same. Transformer auto tap changers ensure that the voltage limits are maintained under positive loads, not negative ones from generators. The changes and associated costs needed to implement your suggestion would in the least require a consultation study and an expensive report? Hold on, has this not already been done? LV Network modeling review with distributed generation, for the DTI. Contractor Econnect.
I like the idea of downgrading to 25A, a current limiter may prove more practical than a fuse though? Just imagine the demand for domestic generators.

[Ivan]

Ecogen,

Thanks - you certainly know your stuff!

The problem I have with G83 is that it's a particular UK variation of the european standard - with peculiarities like the 3minute warm-up period whereas on the continent they require only 10seconds. It's a historical thing, but it hasn't be harmonised, and as a result manufacturers need to certify their products with a specific standard for the tiny UK market - which obviously increases the costs of grid-tie equipment in the UK, relative to the continent.

I thought the government were very much in favour of de-centralised power generation - in which case the auto-tap transformers capable of negative adjustment would be quite high on the agenda. As usual, there's a load of hot air going through parliment, and nothing being done on the ground. Perhaps some of the wasted grant administration money could be replaced by some incentives for the DNOs to get their act together with the transmission system?

I still think that the tiny number of people feeding power into the grid will make a negligible difference to the grid loading (we're talking fractions of fractions of 1%). We're not going to get even 0.01% of the population grid feeding overnight - more like over the next decade or more - which is plenty of time to replace equipment with the newer SSEG-friendly transformers as and when they wear out.

How about a standing charge which is proportional to your incoming fuse/current limiter - like they do in France? If you want to switch on a 100A compressor, then you pay extra. Alternatively, it could be tied into Smart Metering