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Anyone like to look over my proposed SSEG application and diagram?


Elbow

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Hi,

I'm trying to get my SSEG application moving - so I have completed Cape Town's SSEG grid-tie form and made a diagram of my proposed install.

Are there any kind people here who'll take a look for me and see if what I've put in looks reasonable and acceptable?

@The Terrible Triplett I know you've done this application.  @Fuenkli too.

 

PV overview.pdf Application for connection of Small Scale Embedded Generation completed anonymized.pdf

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Had a look. Could not find anything wrong (but I am by no means an expert). I think you could simplify the wiring diagram by removing some of the 2p breakers/isolators. I would also put the power indicator light after the change over switch.  

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6 hours ago, cpbotha said:

@Elbow thank you for posting this!

(I did read through everything, but more from the standpoint of learning from what you wrote. I have that form partially completed in my solar project folder also. :)

Well @Karel gave some input so I made a few tweaks and I've now submitted it.  

So now my head is above the parapet!

Let's see what happens (though I suspect actually nothing much will happen).

I'm in the "sseg.south" area.

I stated that I want to start the install 1 April and commission by the end of the month.  I don't think that's unreasonable, but I think its a lot faster than they are actually working.

 

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10 hours ago, Elbow said:

Well @Karel gave some input so I made a few tweaks and I've now submitted it.  

Best call you could have made.

This application is personal. It is between you, the electrician and the engineer to convince CoCT. 🙂 

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22 minutes ago, The Terrible Triplett said:

Best call you could have made.

This application is personal. It is between you, the electrician and the engineer to convince CoCT. 🙂 

Hi TTT,

Well that is my system as planned - 100% straightforward application.  To the best of my ability I've tried to make it meet the requirements - with some pointers from @Karel.

My background is software and a little electronics.  Ham radio on the side.  But I've been learning this area over the last years and I think I understand the principles at least.

Others should put in their applications with @Karel's help and give him more projects to represent since I think that will help get the process and the requirements smoother.

 

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44 minutes ago, Elbow said:

with @Karel's help a

Karel or @Rautenk ?

45 minutes ago, Elbow said:

Others should put in their applications ...

Jip, have sent his details to as many people as I could. The more we are, the better.

I've engage CoCT direct now ... have posted this elsewhere here, but here it is again, image of email I sent:

image.png.bd0a083d113e1493fd40ec69f57051b1.png

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@Elbow Some comments on your application:

1) On Page 3 you state the maximum peak short circuit current as < 30 Amps. I would expect a figure in the range of 100's to maybe 1000's of amps. Could you please explain how you determined this value?

2) On Page 3 you state the Neutral To Earth Resistance (Ω) "To be measured - required to be <0.35?".  Can you explain where this value came from. I know that the Southern Suburbs electricity department in CT requires the earth electrode on your premises to be < 22 Ω if the supply is < 150 Amps. I am not sure what requirements are placed on your Inverter Earth Electrode though. 

3) On Page 4 "Electrical Parameters Of Generator And Unit Transformers" Should be marked "N/A" as this is not applicable to your Inverter system.

4) On Page 4 "Recording Of Quality Of Supply Devices" Does your open energy monitor record the quality supply parameters as per NRS 048?

 

 

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7 minutes ago, Carl said:

@Elbow Some comments on your application:

1) On Page 3 you state the maximum peak short circuit current as < 30 Amps. I would expect a figure in the range of 100's to maybe 1000's of amps. Could you please explain how you determined this value?

2) On Page 3 you state the Neutral To Earth Resistance (Ω) "To be measured - required to be <0.35?".  Can you explain where this value came from. I know that the Southern Suburbs electricity department in CT requires the earth electrode on your premises to be < 22 Ω if the supply is < 150 Amps. I am not sure what requirements are placed on your Inverter Earth Electrode though. 

3) On Page 4 "Electrical Parameters Of Generator And Unit Transformers" Should be marked "N/A" as this is not applicable to your Inverter system.

4) On Page 4 "Recording Of Quality Of Supply Devices" Does your open energy monitor record the quality supply parameters as per NRS 048?

 

 

Hi Carl,

Thanks for taking the time to look at this.

1) @Rautenk can read my inverter specs better than me and says the figure is 51A.  The original entry I copied from someone else.

2) again copied. I removed it in the meantime since I’m not quite clear on the question. My inverter doesn’t have a separate earth.

3) ok, thanks

4) thanks for the reference. My monitoring doesn’t formally meet this standard - I could do the voltage and fundamental frequency but not the harmonics etc. I’ll drop the reference.  

Thanks again!

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27 minutes ago, Carl said:

1) On Page 3 you state the maximum peak short circuit current as < 30 Amps. I would expect a figure in the range of 100's to maybe 1000's of amps. Could you please explain how you determined this value?

It appears that they want the short circuit current from your inverter here, and that would be something like 200% of your inverter's rating, so for a 3KVA unit that would be something like 30A. Your grid connection would be somewhere around 900A. Mine is 950A for example.

12 minutes ago, Elbow said:

2) On Page 3 you state the Neutral To Earth Resistance (Ω) "To be measured - required to be <0.35?".  Can you explain where this value came from. I know that the Southern Suburbs electricity department in CT requires the earth electrode on your premises to be < 22 Ω if the supply is < 150 Amps. I am not sure what requirements are placed on your Inverter Earth Electrode though. 

Electrician measure mine inside the DB. As close to Zero ohms as you get. Has to be measured with a decent meter, there is sometimes a bit of voltage between these two, so you can't use a normal DMM for it. We additionally did an earth loop test as well and found that mine is around 3 ohms. But it appears they want to see how good your TN bond is, not how good the earth loop is.

 

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Our Multies are still regarded as some kind of Hybrid mish-mash by COCT and there is even a note at the bottom of the inverter list about the changeover switch requirement.

This is now outdated as this was effectively borrowed from the old SANS document which had no concept of a grid synchronized storage based inverter. The new SANS which is effective now does away with this and the Multi is legal for grid tie (and for that matter any battery based inverter that is otherwise NRS-097 compliant).

However, it may take COCT some time to adapt. I hope your application will be successful. Please let us know any comms you get from COCT.

 

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2 hours ago, The Bulldog said:

However, it may take COCT some time to adapt. I hope your application will be successful. Please let us know any comms you get from COCT.

Will do.  So far it's complete silence, not even an acknowledgement that my application was received..

 

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@plonkster and @The Bulldog 

On 2019/03/11 at 9:49 AM, The Terrible Triplett said:

I've engage CoCT direct now ... have posted this elsewhere here, but here it is again, image of email I sent:

In reply to my email, this is what CoCT replies with:

In MY case I have a Victron Multigrid as per the approved CoCT list. I bought it because it is on the list, with no notes on it. [Refer to the following note on the City’s Approved inverter list ‘6. All grid-tied hybrid inverters shall be equipped with a separate suitably interlocked change-over switch as specified in the Requirements for small scale embedded generation (SSEG) document.’]

 Why does it need a "separate controllable switch" when the Victron inverters on the list all have one built in already with VDE certification? [RSA and City safety requirement. SANS 10142-1: 2017 specifies the transfer switch safety standard ‘SANS 60947-6-1/IEC 60947-6-1, Low-voltage switchgear and control gear – Part 6-1: Multiple function equipment – Transfer switching equipment’. The registered person [electrician] that issue the electrical Certificate of Compliance must complete Section 4, Clause 14 of the Test report, i.e. ‘Where an alternative supply is installed, it complies with the requirements in respect of connections, change-over switch and indicator’ for any hybrid grid-tied inverter that must isolate an interconnected circuit from the grid before the storage system is used.]

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5 minutes ago, The Terrible Triplett said:

In reply to my email, this is what CoCT replies with:

So did that answer your question? 😛

6 minutes ago, The Terrible Triplett said:

for any hybrid grid-tied inverter that must isolate an interconnected circuit from the grid before the storage system is used

The Multi (none of them) doesn't do that. No Hybrid that I know of does that. So they are technically all illegal from an (old) SANS viewpoint. But as has been pointed out, it seems SANS is changing to allow it. The only question is whether it will happen before end of May.

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18 minutes ago, plonkster said:

So did that answer your question? 😛

The Multi (none of them) doesn't do that. No Hybrid that I know of does that. So they are technically all illegal from an (old) SANS viewpoint. But as has been pointed out, it seems SANS is changing to allow it. The only question is whether it will happen before end of May.

No, it did not. 🙂 

Do you or Bulldog have the latest paragraph to disprove the (old) SANS regulation?

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Only the draft I found and posted the link to. I note the 2018 version is available to purchase from SABS now so that means it is law now.
The draft is from October 2018, I doubt that there will be much changed in the final release but the text makes a good read and appears to be "free".

All references to switches have gone away and there is a drawing of a battery based inverter/solar system shown as example diagram - grid tied and no switch in sight.

A possible problem is COCT - they may make their own rules on top of SANS if they so wish. So if they think they have good reason why they do not want a hybrid inverter tied to the grid then they can add that requirement on top of SANS as this does not violate SANS in any way. It just means your inverter will not work the way the manufacturer intended.

Note the requirement is not qualified to the way a hybrid works - it does not matter if you use ESS or the "old" way of using the transfer switch or anything else - the system is expected to have an external interlocked changeover switch. No more, no less.

Yes, it's exceedingly frustrating and obstructive. For the life of me I cannot understand why this is in their requirements. Grid tied inverters using other power sources than direct PV connections have been around for many years now and are safe for use.

 

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8 minutes ago, The Bulldog said:

the requirement is not qualified to the way a hybrid works

Well, of course there are ways of making a hybrid that would allow compliance with this. It's just that I don't know a single one presently on the market that works that way. And if you do it that way, you cannot do peak-shaving using the battery.

The route of least resistance for Cape Town would be to use the latest SANS. Otherwise I propose a class action suit because their list caused a bunch of us to buy things that were not legal... 🙂

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14 minutes ago, plonkster said:

Well, of course there are ways of making a hybrid that would allow compliance with this. It's just that I don't know a single one presently on the market that works that way. And if you do it that way, you cannot do peak-shaving using the battery.

The route of least resistance for Cape Town would be to use the latest SANS. Otherwise I propose a class action suit because their list caused a bunch of us to buy things that were not legal... 🙂

You can configure the multi to switch an external contact based on the state of the transfer switch. So you could simply install two mechanically interlocked contactors or a motorized contactor (it would still need to be interlocked). This allows you to use the Multi in the old fashioned way. I used to run mine this way until somebody thought ESS would be a smashing idea (it was). 

I made up a string of assistants that would switch to grid based on SOC (from an external BMV connected to an input on the Multi), then a couple of load based ones like "switch to grid if power demand greater than 2000W for 2 minutes" and "switch to grid if power demand greater than 3000W for 1 minute" and a couple more like that complete with the reverse like "switch to inverter if demand less than 1500W for 1 minute" or whatever.

It worked quite well. It does have some issues: The first is the annoying "CLACK" when the bypass switch does its thing. The second was the Multies insistance to synchronize to grid before switching the contactor to grid (and the inverter off). That is nice since it avoids the fat spark over the contacts and gives a smooth transistion but it takes a few seconds so if you have a sudden load that way exceeds what the Multi can handle everything falls over.

ESS on the other hand: Bliss. Pure Bliss. Best thing since sliced bread. Did I mention that I like it ? Now I am loosing it and going to a primitive PV grid tie. Oh well, the journey has been fun...

 

Edited by The Bulldog
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1 hour ago, The Terrible Triplett said:

@plonkster and @The Bulldog 

Where an alternative supply is installed, it complies with the requirements in respect of connections, change-over switch and indicator’ for any hybrid grid-tied inverter that must isolate an interconnected circuit from the grid before the storage system is used.'

 

Trying to read this like a lawyer, and apply this to the architecture of my hybrid grid-tied inverter.

Here's the block diagram of my inverter.

 

It seems that to implement their requirement it would be necessary that the safety relay be opened any time that the inverter relay was closed?

If there was a program mode where the safety relay was open whenever the inverter relay was closed would that do the job?  Since all the local energy sources - batteries and panels - are to the left of that inverter relay.  

It would mean that this was no longer a grid-tie inverter since it can never push power back to the grid.

Is this what they want?  'Cos that boils down to no grid-tied inverters.  But if no grid-tied inverters can be approved why is there an application for SSEG with grid-tying?

I'm not sure why the storage system is a special case - since the electricity coming from the panels is no different from that coming from the batteries?  But if it is specifically a battery question then perhaps whenever the control turns the battery module to discharge then we open the safety relay.

I don't understand what the objective is.

The whole idea of these hybrids is that they can freely shovel power around between panels, batteries, AC out and Grid in/out.  So this requirement seems to break that.

If an external switch is required I'm still stuck not understanding exactly what this external changeover switch is supposed to change over between and in what circumstances?

 

 

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Edited by Elbow
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31 minutes ago, plonkster said:

Otherwise I propose a class action suit because their list caused a bunch of us to buy things that were not legal... 🙂

Rather start with getting @Rautenk to co-ordinate a meeting with Brian Jones.  Perhaps with a few of you "lay experts" along and to atttempt to find a good solution together.

I've put in quite a bit so a few thousand more to buy the gizmo they say I must have isn't out of the question.  Only no-one knows what gizmo will satisfy them?  For me I'm not even clear what problem the gizmo is trying to solve and when it must be opened.

My companies offices are at Black River park which was the first "headline" PV project and the one on the cover of https://www.esi-africa.com/wp-content/uploads/2016/06/Brian-Jones-.pdf

Edited by Elbow
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The requirement that you can only connect storage AFTER disconnecting the grid is a complete deal breaker. It means you can't run a grid-parallel battery. You can't do peak shaving from battery. This rules out pretty much any energy storage system: SunnyIsland (in some modes), Goodwe, Victron, even Tesla powerwalls.

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I'm sticking my neck out ... hope you guys don't mind me using YOUR words. 🙂

I cannot delete ... I'll repost now.

 

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