1 hour ago, Hannes7212 said:

I would find it amusing but coming from this guy it is not.

Drop me a PM of who you spoke to?

2 hours ago, Hannes7212 said:

This is why:  If the inverter goes into "bypass" mode due to low battery / solar conditions the sudden demand on the network is what they are concerned about

This sounds halfway right. The issue is indeed the pick-up rather than the feed-in. If you have a 5KVA inverter and it transfers the full load back to the grid, then they have to pick up 5KVA.

The reason I only think it is halfway right is that the argument is more applicable to grid-tied units BECAUSE they have identical parameters. A disturbance that trips one inverter trips the entire neighbourhood. The concern is literally that instabilities in the grid are made worse by too much PV.

This is of course not applicable to to switching UPSes. A grid disturbance is much more likely to remove load from the grid than to transfer it to the grid.

So it seems to me you are in a bit of a gray area.

5 hours ago, plonkster said:

o it seems to me you are in a bit of a gray area.

How so? It is on a changeover switch, which is loose from the grid, so how can that be a gray area?

EDIT: Remember, Axperts cannot even charge the batteries from the grid if installed as off-grid?

Edited June 5, 20197 yr by Guest

If the "sudden demand" narrative catches on then there will be a ban on geysers and underfloor heating following shortly.

Never heard of a "25% of supply max demand limit" and council has already set a precedent with numerous off-grid systems identical to the above having been approved so I think someone just had a bad day...

 

4 hours ago, The Terrible Triplett said:

EDIT: Remember, Axperts cannot even charge the batteries from the grid if installed as off-grid?

His system is not "off grid". He's got the automatic changeover where it might move the entire load back to the grid when a cloud passes. Note: I actually disagree with CoCT here, but I am being pedantic about understanding their reason correctly before reaching for our pitchforks 🙂

15 minutes ago, PeterP said:

sudden demand

I believe the proper reason is "sudden demand when you can least afford it", which would be what happens when you have several large grid-tied inverters and a disturbance that moves the grid outside the normal operating range. What you have then is a problem that gets exacerbated. That would be like hundreds of people turning on two geysers at the moment there is a small power dip. So it is more nuanced than just "sudden".

Of course there is a second kind, which is the "moving cloud" scenario. With lots of grid-tied capacity, you get a Mexican wave of playing pick-up.

In both cases, I think an off-grid inverter with a switch reacts sufficiently different that it ought to be allowed a larger limit. A passing cloud won't send it back to the grid immediately. A disturbance in the supply itself will be treated with UPS action: Relieving the load from the grid. There'd probably still need to be a limit, but it seems unfair to use the grid-tied rules.

5 minutes ago, plonkster said:

 There'd probably still need to be a limit, but it seems unfair to use the grid-tied rules.

might as well make a "No coffee until after 9am" - rule.......An off-grid system can only put less stress on the grid, to say otherwise is non-sensical. Any load carried by the off-grid system would, in it's absence, have to be carried by the grid and saying the demand is more sudden when switching over is problematic means switching on/off your mains at DB board is equally problematic.

1 hour ago, PeterP said:

No coffee until after 9am

Well... now here is an interesting story I can tell you. Brits, tea and Netflix. With traditional television, you have massive electricity surges every time a popular television episode finishes as large numbers of Brits turn on the kettle for a cup of tea. With the advent of streaming television... no more surges. The exception is sporting events and other things that are broadcasted live.

The point I am making is that it strains the grid when everyone does this at the same time, and with grid tied inverters they literally all do it at the same time because every one does what the NRS097 overlords told it to do. My point is also that a switching UPS (I don't want to call it off-grid, because it is not completely off-grid) does not follow these rules, and therefore cannot be judged by the same measure.

But on the other hand, I am arguing that such inverters aren't completely neutral either. They do cause the same effect on a macro level, namely that on a cloudy day the demand will be higher, and as clouds roll in from the South West (as they do here) you will have an escalating wave of such inverters piling back onto the grid. The more of these you have installed (and the larger they are), the bigger that effect will be. I think a 3.5kva limit is too low a limit for these systems, but I think 10kva might be too high (for a single phase system). An entirely different argument has to be made for and against these.

Even the use case of a UPS, which transfers the whole load back once the grid returns, is not really helpful here. A UPS prefers to run from the grid and falls back to batteries when it must. An SSEG system prefers to run from the batteries/PV modules and fall back to the grid when it must, and generally all of them find that they must more or less at the same time, give or take a few hours.

So yes... I am doing that thing where I am agreeing with both sides. It's infuriating... I know 🙂

Edited June 5, 20197 yr by plonkster

Plonkster I don't agree - the UPS/off-grid system will fall back to grid when battery capacity is too low - it's highly unlikely that all such installed systems will run out of battery at exactly the same time. The television tea episode would be more of an impact and if they didn't find a way of legislating away the tea-break then I don't see the need here.

Just now, PeterP said:

when battery capacity is too low

And with the large amount of small-batteried-I-just-want-to-use-my-solar-power-for-loads crowd, this will happen within an hour or two of the clouds rolling in.

(I really hate the small battery crowd... because they turn their financial troubles into technical troubles with their oversized PV arrays and large inverters... but that is another matter).

See this article for more info. What I think is happening here is there is was not sufficient thought given to these kinds of systems. and now they are judged by the grid-tied rule-book. This creates problems both ways.

Don't get me wrong. I don't think a 5KVA inverter is a problem in this setting. Picking up 5KVA on a 15KW single phase installation is something the grid is expected to do often, and on a time scale that is closer to hours than to seconds, most certainly so. But it can't be blanket unlimited either.

(Also... I had one case up North of a guy who installed 45KW hybrid power onto a single phase home... people do some really bad things sometimes).

14 hours ago, Hannes7212 said:

So my question to this group is

@Rautenk do you agree with the ruling of the CoCT to apply the 3.6kW limit for non GTI's (like the Axperts)? Did this point come up in your meeting with Reyno? I think they are going to far here.

13 hours ago, The Terrible Triplett said:

Did you register your system as off-grid or did you fill in the forms for grid tied?

No I filled in the proper "DECLARATION FOR OFF-GRID SMALL SCALE EMBEDDED GENERATION" form

13 hours ago, The Terrible Triplett said:

Drop me a PM of who you spoke to?

How do I do that?  LOL sorry

 

7 hours ago, The Terrible Triplett said:

How so? It is on a changeover switch, which is loose from the grid, so how can that be a gray area?

EDIT: Remember, Axperts cannot even charge the batteries from the grid if installed as off-grid?

No it is true that if it goes to bypass mode it will draw from the grid.  And it can be set to charge from the grid as well.   The change over is actually on the output line to bypass the system.

Edited June 5, 20197 yr by Hannes7212
typo

13 minutes ago, Hannes7212 said:

No it is true that if it goes to bypass mode it will draw from the grid.  And it can be set to charge from the grid as well.   The change over is actually on the output line to bypass the system.

Ok, I am now totally confused. Way I have it is if you install off-grid, same as a generator, then there is no connection between the Axpert / generator and a DB board. You literally have to switch the changeover from one power source to the next, i.e. the Axpert cannot charge the batteries from the grid, only panels.

Anything else is a dispute brewing. 🙂 

18 minutes ago, Hannes7212 said:

How do I do that?  LOL sorry

Hover your mouse over of the Elephants, click send a message. 🙂 

2 hours ago, plonkster said:

His system is not "off grid".

And therein the start of yet another dispute. 🤔

The more brains, the more ideas, the more conflicting points of views, the more regulations, the more arguments ... pitchforks ... when I am Pressi, ag, you know what, just hold my beer ...

No seriously, way I see it, stick to grid tied with the NRS list of inverter and then the NRS limits on them inverters or be like basta that, and go off-grid and be your own boss.

I pretty much see it this way.

1. Why do we have a 3.5kw limit? To limit the pick-up.

2. Does off-grid/switching inverters create pickup patterns? Yes they do.

3. Is the pick-up pattern the same as for a grid-tied unit? No it isn't.

4. Is there a problem? Possibly... but it's a slightly different problem than for grid-tied.

Hence applying a limit seems fair to me, but applying the grid-tied limit seems unfair. That's just my opinion though.

@Hannes7212 mentioned in one of his earlier posts that the inspector DID NOT have an issue with the inverter brand although, as far as i see, it is not off-grid. that is the initial point which struck me. as to the other argument for not issuing the permit is concerned the reasoning behind it does not make sense to me - coct has to explain here.

or am i totally out of my depth here 🤔

On 2019/05/06 at 7:56 PM, PeterP said:

"CoCT just wants you to register your off-grid system so that they don't have to go and check each one. Pretty fair if you ask me AND it saves on our rates and taxes ito salaries to police it all. EDIT: They apparently send someone to your house to confirm it is off-grid."

The wording on CoCT website clearly states that they must give authorisation for off-grid systems + they issue an approval letter to confirm this. Original website wording merely stated that one must declare (register) system - the goal posts have changed, and yes they have been sending inspectors around to confirm systems are off-grid.

If one has an off grid system, and I am referring to a stand alone system that is isolated from the municipal electrical grid and at no point will have any electrical connection to the municipal electrical grid, I feel it can be defended in a court of law that this situation is one's own private business and no one can force you to register or declare that you have such a system on your private property.

Section 14 of the South African constitution gives all citizens the right to privacy, and this as I understand is what was used in the Constitutional court ruling that legalised the growing and consumption of marijuana for personal and private consumption.

I see the installation of pv panels (planting marijuana) and using the electricity for one's own private consumption (smoking the marijuana) and synonyms under the right to privacy ruling.

17 hours ago, Hannes7212 said:

Ok, that is true for a grid tied system, but this is not a grid tied system.  We have proven lab results showing it is not and it cannot feed back.  I send all this documentation in, along with the argument that the size of the PV array is not relevant either as the PV power cannot ever make it back to he grid - it charges the batteries.  This argument gets accepted and I start to feel happy again.

hi hannes,

although i am not in cape town, we guys in vredenburg [or country-wide] will have similar regulations and your system and mine seem more or less the same. i read the above with interest as it might become a relevant argument in my case. initially i wanted to pm you on this but feel it might be beneficial info for other axpert owners on the forum, especially in the light of "This argument gets accepted and I start to feel happy again." and the fact that the inspector did not ground you on the fact that you have an axpert.

would you be willing to share mentioned 'documentation' and the documented 'acceptance' of the coct?

7 minutes ago, Power Me said:

Section 14 of the South African constitution gives all citizens the right to privacy, and this as I understand is what was used in the Constitutional court ruling that legalised the growing and consumption of marijuana for personal and private consumption.

when i see our constitution an old saying comes to mind... 'it is either vague for voidness or void for vagueness' as it wants to be as pc as possible 🤪

4 hours ago, plonkster said:

I pretty much see it this way.

1. Why do we have a 3.5kw limit? To limit the pick-up.

2. Does off-grid/switching inverters create pickup patterns? Yes they do.

3. Is the pick-up pattern the same as for a grid-tied unit? No it isn't.

4. Is there a problem? Possibly... but it's a slightly different problem than for grid-tied.

Hence applying a limit seems fair to me, but applying the grid-tied limit seems unfair. That's just my opinion though.

Good summary and I think I agree with it.

2 hours ago, Gabriël said:

hi hannes,

although i am not in cape town, we guys in vredenburg [or country-wide] will have similar regulations and your system and mine seem more or less the same. i read the above with interest as it might become a relevant argument in my case. initially i wanted to pm you on this but feel it might be beneficial info for other axpert owners on the forum, especially in the light of "This argument gets accepted and I start to feel happy again." and the fact that the inspector did not ground you on the fact that you have an axpert.

would you be willing to share mentioned 'documentation' and the documented 'acceptance' of the coct?

Hi, yes I am sure it is ok to share the discussion:

The first reply on the application:

Good day

Please use ref no: 30327856 in all correspondence to this office.

On a 60Amp single phase connection the total capacity of embedded generation
allowed is 3,5kVA.

5kVA as filled in on your application is not allowed.

This application as it is now cannot be approved

My reply:

Hi Leon,

I do not understand your reference to the breaker size vs generator size as
that is only applicable to a grid tied system.  This client has a UPS
installation with PV generation to charge the batteries.

I trust that clarifies it a little better.

Regards,
Hannes

Leon's reply (CoCT):

Good day

Unfortunately no

All system connected to the internal wiring of a premises via a changeover
switch falls under the 25% limitation, off grid and on grid

My Reply:

Hi Leon,

Thank you for taking the time to answer.  Help me understand please:

If the device that you call the "generator" has no way whatsoever of generating power on it's AC input side (the side connected to the City's grid via a breaker), would the City still impose the 25% generation limit?

To be more clear, what I am asking is exactly the same as asking if I can connect a load like a tumble dryer to my residential DB board that exceeds 25% of the amp rating of my main breaker.

Please do not think I am trying to be sarcastic or clever, I am merely trying to illustrate that we are not in any way talking about a generator here as far as the grid is concerned when we are talking about the AC inverter component of an off grid system.  The PV that does the generation is not connected to the AC supply from the City, it charges the battery bank only.

As I said before, I do understand this argument is not true for a grid tied inverter (battery inverters as well) such as the SMA Sunny Island range of inverters.

What I am talking about is only for devices where we can prove that it cannot feed back power to the City's grid.  We understand why this is important and went to great lengths and expense to prove this for the inverters we use for "off grid" installations on the City's network.

Again I say thank you for taking the time to respond so we can get to the technical root of the concern so that we can address it from the installers side.

Regards,

Hannes

Leon's reply:

Good day

On application ref no : 30327856.

No single line was provided with the application.  Please provide the single line so that I can see what you are trying to explain.

 

My reply:

Hi Leon,

I appologize if the client did not send all the documentation we provided in.  I have attached it.

Regards,

Hannes

 

Leon's reply:

When you design a residential development a ADMD of normally 5.31kVA (medium size house) or 4.04kVA (small house or flat) are being used to design the electrical network.

The power that the SSEG system generates may not be higher than the ADMD of a domestic house that is connected via a change over switch as the supply of the UPS DB board is shared between our grid and the SSEG system.

If our grid has to pick up a load of the UPS DB board that exceeds the ADMD of the design standards upon change over of the change over switch it can destabilize our LV network.

For the above reason City of Cape Town has decided that the 25% limit will be placed on the above off grid SSEG applications.

Please note that the system as in the single line as provided is a Passive standby UPS utilised as off-grid hybrid SSEG.

For stand alone off grid system that is not connected in anyway to the internal wiring of the domestic premises or the grid the 25% does not apply.

 

Hannes again:  This was the end of the email conversation.  At this point I phoned Ryno van der Riet (Leon's senior I believe) and he basically confirmed all of above.

In the mean time we are sitting on quite a few other applications that were approved (often larger systems on single phase) by other areas in Cape Town,  I did not want to start this discussion yet out of fear of making life difficult for the clients that were approved or other officials in CoCT's employ.

 

I am also attaching the document I refer to in the email proving the "non grid tied nature" of the Axperts.  It is called a LynX 5k in the report as this was done for the inverters SolarMD imports directly from Voltronic, rebranded as Lynx.  It is the Axpert MKS inverters.

Addendum to Declaration of Compliance of SMD LynX 5K Inverter to NRS097_ 22 Oct '18 (Final).pdf

@Hannes7212 - what is meant by this line:  "Please note that the system as in the single line as provided is a Passive standby UPS utilised as off-grid hybrid SSEG."

That is a list of all possible classifications of inverters mixed together in one line?

5 hours ago, plonkster said:

I pretty much see it this way.

1. Why do we have a 3.5kw limit? To limit the pick-up.

2. Does off-grid/switching inverters create pickup patterns? Yes they do.

3. Is the pick-up pattern the same as for a grid-tied unit? No it isn't.

4. Is there a problem? Possibly... but it's a slightly different problem than for grid-tied.

Hence applying a limit seems fair to me, but applying the grid-tied limit seems unfair. That's just my opinion though.

1. The 3.5kVA limit is there to ensure all grid-tied SSEG customers remain net-consumers (import more than they export) + to limit excessive feed-back. The UPS/Off-grid generator cannot export hence this does not apply.  

2. I don't see what patterns they create that are any different to flicking a switch on any appliance - home-automation could create the same patterns. The grid merely picks up what ever load that was being serviced by generator - none more, none less and entirely identical to what would have been serviced by grid prior to generator installation.

3. Correct - the grid-tie system is synchronised and load is shared between grid and generator, whereas the generator picks up the load in its entirety. 

4. No problems that wouldn't have been there prior to generator being installed as loads remain the same whether serviced by grid or generator.

In lieu of above I don't see any need for limits on off-grid/UPS systems as they are not adding any stress that wasn't already there. It's akin to saying you are only allowed to use 15.75A of your 63A Eskom supply - if that's the case then what are the 63A breakers for?