Batteries connected to PV PCE
Batteries connected to PV PCE
Do batteries connected to an inverter fall under mains parallel generation? Or is it simply switchboard through to PCE high risk, PV install high risk, batteries general risk?
Re: Batteries connected to PV PCE
I don't believe that's the intent; and they are certainly not in parallel with " mains";
whereas they inverter output is.
However
ESR 4 defines MPGS using 2 criteria:
(a) are used or intended for use by any person in, or in connection with, the generation of electricity for that person’s use; and
(b) are capable of supplying electricity to fittings that, at the same time, are supplied with electricity from other systems of electrical supply.
Batteries meet a); no question.
They generate (convert energy from one form to another (chemical > electrical).
But in the case of a PV sytem with batteries attached, both the batteries ans the PV array are generating systems.
The question is whether they are connected in parallel.
Which depends on how each is connected to the inverter.
If b) of the definition referred to " mains" this ambiguity wouldn't exist; because def of "mains" ties to PoS, which would therefore mean - as the term MPGS indicates - that only sources in parallel with mains would be included.
whereas they inverter output is.
However
ESR 4 defines MPGS using 2 criteria:
(a) are used or intended for use by any person in, or in connection with, the generation of electricity for that person’s use; and
(b) are capable of supplying electricity to fittings that, at the same time, are supplied with electricity from other systems of electrical supply.
Batteries meet a); no question.
They generate (convert energy from one form to another (chemical > electrical).
But in the case of a PV sytem with batteries attached, both the batteries ans the PV array are generating systems.
The question is whether they are connected in parallel.
Which depends on how each is connected to the inverter.
If b) of the definition referred to " mains" this ambiguity wouldn't exist; because def of "mains" ties to PoS, which would therefore mean - as the term MPGS indicates - that only sources in parallel with mains would be included.
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Re: Batteries connected to PV PCE
In this case they connect via a plug in conncetor.
I guess maybe it could change if they are AC coupled or DC coupled?
I was just asked the question by a client when doing a PV inspection if they would need an inspection of the batteries if installed at a later date.
Initial thought was no in this case.
I guess maybe it could change if they are AC coupled or DC coupled?
I was just asked the question by a client when doing a PV inspection if they would need an inspection of the batteries if installed at a later date.
Initial thought was no in this case.
Re: Batteries connected to PV PCE
Not sure what you mean by a.c. coupled, as batteries are always d.c..
Regardless; I don't believe connection of batteries to a PV - inverter system requires inspection.
The (installation of) PV requires inspection if above ELV .
While there are differences of interetation of what "associated with" means; ES have published a clear statement that they don't regard PV at ELV to be HRPEW.
And the (installation of) inverter needs inspection (if capable of operating in parallel with mains (or any other LV a.c source ?).
Once this is in service, adding a battery doesn't clearly match up with any of the listed categories of HRPEW;
The batteries may be connected in parallel with the PV.
More likely they will be separately connected to the inverter; with the "inverter" also serving as battery charge regulator.
The internal connections for this are very unlikely to amount to "connected in parallel"
The batteries will never be in parallel with "mains".
Therefore I don't believe they are intended to be included as being "mains parallel" generation.
However the wording of the definition does include any cases where generation sources are connected in parallel, including generation at ELV
eg 2 x PV arrays, or 2 x battery banks, or a PV & a wind generator, or PV & battery.
I suspect the writer of this definition was suffering from the same problem as the writers of Clause 7.3 of "3000"; which - incorrectly - classifies an inverter as a "generation system".
An inverter is a form of "electricity converter".
The input may be at ELV or at LV, but it's always d.c.
the form of the electricity (voltage and frequency) is changed, but it's still electrical energy in, and electrical energy out.
The form of the energy doesn't change; which is what "generation" is about.
IE converting some other form of energy into electrical energy; eg wind , hydro & engine-driven all convert from kinetic, batteries convert from chemical.
Regardless; I don't believe connection of batteries to a PV - inverter system requires inspection.
The (installation of) PV requires inspection if above ELV .
While there are differences of interetation of what "associated with" means; ES have published a clear statement that they don't regard PV at ELV to be HRPEW.
And the (installation of) inverter needs inspection (if capable of operating in parallel with mains (or any other LV a.c source ?).
Once this is in service, adding a battery doesn't clearly match up with any of the listed categories of HRPEW;
The batteries may be connected in parallel with the PV.
More likely they will be separately connected to the inverter; with the "inverter" also serving as battery charge regulator.
The internal connections for this are very unlikely to amount to "connected in parallel"
The batteries will never be in parallel with "mains".
Therefore I don't believe they are intended to be included as being "mains parallel" generation.
However the wording of the definition does include any cases where generation sources are connected in parallel, including generation at ELV
eg 2 x PV arrays, or 2 x battery banks, or a PV & a wind generator, or PV & battery.
I suspect the writer of this definition was suffering from the same problem as the writers of Clause 7.3 of "3000"; which - incorrectly - classifies an inverter as a "generation system".
An inverter is a form of "electricity converter".
The input may be at ELV or at LV, but it's always d.c.
the form of the electricity (voltage and frequency) is changed, but it's still electrical energy in, and electrical energy out.
The form of the energy doesn't change; which is what "generation" is about.
IE converting some other form of energy into electrical energy; eg wind , hydro & engine-driven all convert from kinetic, batteries convert from chemical.
Re: Batteries connected to PV PCE
Thanks Alec
Just for your reference and understanding.
https://www.energysage.com/energy-stora ... d-to-know/
There are multiple web pages with info on this. It's a common term in this industry.
Just for your reference and understanding.
https://www.energysage.com/energy-stora ... d-to-know/
There are multiple web pages with info on this. It's a common term in this industry.
Re: Batteries connected to PV PCE
Thanks for that link.
However this site is not using correct technical language; it's jargon.
Nothing wrong with jargon; provided everyone in the discussion knows which flavour is being used.
In this case it's clearly intended to inform non-technical people; but is (mis-)using technical terminology.
So it doesn't match up to the technical (and legal) languages of ESRs.
Bad enough matching ESRs to Standards, when some terms are defined differently for each.
Bring this type of jargon into a technical / legal discussion; and the only result possible is confusion.
So while it's sort of OK for them to say the d.c. is "transformed (via inverters)";
that's explanation for the non-technical and is technically incorrect.
But such sloppy language has no place in a technical / legal discussion.
There is no such thing as a "solar battery".
If there were such a thing, it would store solar radiation.
What's being discussed is a chemical battery, which accepts (d.c.) electrical energy, converts it to chemical energy - in which form the energy can be stored - and also, as required, re-converts back to (d.c.) electrical energy.
Always d.c. on both input and output; though in some cases very far from smooth d.c.
Similarly there's no such thing as a "solar inverter", it's just an inverter;
ie a device for converting d.c to a.c (and in terms of Standards, a form of "electricity converter".
Our industry has capacitive coupling, magnetic coupling, and inductive coupling;
which are all describing the influence of one thing on another to which it is not physically connected.
An example of magnetic coupling is a transformer; which alters the voltage, but not the frequency, of the electricity.
Batteries are not coupled to anything, they are connected.
Even the latest "wire-less" battery charging isn't coupling the battery to anything; the coupling is between a charging circuit built into the battery-powered device and the (typically wired ) source of the electrical energy.
Neither the "a.c coupling" nor the "d.c coupling" terms used in these explanations-to-lay-people describes any kind of "coupling".
Rather these terms are being used to describe whether the charging of the battery is from a d.c. input of the inverter or an a.c. output.
Noting that in the latter case the inverter may be not just an inverter, but an inverter / charger.
Two distinct and separate functions; even when built into one box.
The description of 'a.c. coupling' says "AC power can then flow to your home appliances or go to a battery inverter that converts the electricity back to DC for storage. "
There's NO 'battery inverter' involved.
It's a battery charger (which combines the two separate functions of transforming the voltage and then rectifying it from a.c. to d.c.).
------------------
Enough rant.
However be aware that even Standards can misuse terminology; eg "3000" (incorrectly )deems an inverter to be a form of generator.
And ESRs are largely written by lawyers with little understanding of the technical stuff they are trying to regulate.
Back to the matter of whether adding a battery requires inspection.
In NO case is such a battery connected in parallel with either the mains or any other a.c. "generating system".
In some cases the battery may be in parallel with one or more "other systems of supply"; eg PV or micro-hydro or another battery.
For use with grid-connected inverters, commonly each of the d.c. components will be buffered through a intermediate device, and it's these intermediate devices that may be connected in parallel.
And generally, for PV-on-the-roof type systems, all these sub-systems will be interconnected only within the ' inverter;
which will not be just an inverter but will also serve other functions.
There may be no direct connections that could properly be described as "in parallel" at all.
So, while it's possible that ESRB or District Court might consider such parallel connection of d.c. systems to fall within the current definition; I doubt they would take that approach given the clear reference to 'mains" in the term itself.
However this site is not using correct technical language; it's jargon.
Nothing wrong with jargon; provided everyone in the discussion knows which flavour is being used.
In this case it's clearly intended to inform non-technical people; but is (mis-)using technical terminology.
So it doesn't match up to the technical (and legal) languages of ESRs.
Bad enough matching ESRs to Standards, when some terms are defined differently for each.
Bring this type of jargon into a technical / legal discussion; and the only result possible is confusion.
So while it's sort of OK for them to say the d.c. is "transformed (via inverters)";
that's explanation for the non-technical and is technically incorrect.
But such sloppy language has no place in a technical / legal discussion.
There is no such thing as a "solar battery".
If there were such a thing, it would store solar radiation.
What's being discussed is a chemical battery, which accepts (d.c.) electrical energy, converts it to chemical energy - in which form the energy can be stored - and also, as required, re-converts back to (d.c.) electrical energy.
Always d.c. on both input and output; though in some cases very far from smooth d.c.
Similarly there's no such thing as a "solar inverter", it's just an inverter;
ie a device for converting d.c to a.c (and in terms of Standards, a form of "electricity converter".
Our industry has capacitive coupling, magnetic coupling, and inductive coupling;
which are all describing the influence of one thing on another to which it is not physically connected.
An example of magnetic coupling is a transformer; which alters the voltage, but not the frequency, of the electricity.
Batteries are not coupled to anything, they are connected.
Even the latest "wire-less" battery charging isn't coupling the battery to anything; the coupling is between a charging circuit built into the battery-powered device and the (typically wired ) source of the electrical energy.
Neither the "a.c coupling" nor the "d.c coupling" terms used in these explanations-to-lay-people describes any kind of "coupling".
Rather these terms are being used to describe whether the charging of the battery is from a d.c. input of the inverter or an a.c. output.
Noting that in the latter case the inverter may be not just an inverter, but an inverter / charger.
Two distinct and separate functions; even when built into one box.
The description of 'a.c. coupling' says "AC power can then flow to your home appliances or go to a battery inverter that converts the electricity back to DC for storage. "
There's NO 'battery inverter' involved.
It's a battery charger (which combines the two separate functions of transforming the voltage and then rectifying it from a.c. to d.c.).
------------------
Enough rant.
However be aware that even Standards can misuse terminology; eg "3000" (incorrectly )deems an inverter to be a form of generator.
And ESRs are largely written by lawyers with little understanding of the technical stuff they are trying to regulate.
Back to the matter of whether adding a battery requires inspection.
In NO case is such a battery connected in parallel with either the mains or any other a.c. "generating system".
In some cases the battery may be in parallel with one or more "other systems of supply"; eg PV or micro-hydro or another battery.
For use with grid-connected inverters, commonly each of the d.c. components will be buffered through a intermediate device, and it's these intermediate devices that may be connected in parallel.
And generally, for PV-on-the-roof type systems, all these sub-systems will be interconnected only within the ' inverter;
which will not be just an inverter but will also serve other functions.
There may be no direct connections that could properly be described as "in parallel" at all.
So, while it's possible that ESRB or District Court might consider such parallel connection of d.c. systems to fall within the current definition; I doubt they would take that approach given the clear reference to 'mains" in the term itself.
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