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COCT Grid Tie regulations


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Hey everyone, I have started the long process of reading through the relevant regulations for a grid tie (Hybrid and non-hybrid) setup based on the COCT regulations, but have some questions which i'm hoping someone can help with. 

1. All inverters for new installations must be compliant to the new sans NRS097-2-1 2017.

The list published by COCT has both 2010 and 2017 compliant units, any inverter for new installations (post Dec 2018) would require NRS097-2-1 2017 certification? Otherwise it would be rejected by COCT? Anyone know how hard it would be to have additional units certified by COCT? So even if its 2010 version compliant, you would not be able to register it on a new application?

2. Grid tied hybrid needs to be connected via a changeover switch, suitably rated. 

A specific changeover switch with break before make is required. Whether automatic or manual. This would imply that there will always be a slight dip during the changeover? Minimum requirement of 20ms. Do you know of a switch which actually satisfies all the requirements?

3. Grid tie non hybrid

No transfer switch required? but unit must shut off during loss of grid, i.e. shouldnt be able to island itself? Addition of batteries makes it Grid tie hybrid and requirements of 2 above takes over?

4. What is a suitably rated reverse power flow blocking relay?

In the case of running a grid-tie with a prepaid meter, there is a requirement of reverse power flow blocking? What would a suitable blocking relay be? Or is this a function built into the 2017 compliant inverter?

5. NERSA Approval

While COCT state they are not requiring approval for less than 1MVA from NERSA, it still makes provision for incase NERSA does make this a requirement in the future. How likely would this be?

6. Off grid setups

Does not require COCT approval, but they need to be informed? and a COC to proof electrically separate from grid connection. 

Lastly, has anyone successfully had a grid tie SSEG approved by COCT? What are the approximate timelines / response time to expect from the city?

Thanks in advance for help!

 

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7 hours ago, MuKi said:

any inverter for new installations (post Dec 2018) would require NRS097-2-1 2017 certification?

It's been moved out to December 2019. If you get it signed off before then, and you don't modify the installation, then it remains legal. From 2020 onwards these inverters will either need recertification, or you won't be able to use them.

7 hours ago, MuKi said:

A specific changeover switch with break before make is required.

Been discussed to death elsewhere. It seems a normal changeover switch on the output (properly interlocking etc) is all they want.

7 hours ago, MuKi said:

No transfer switch required? but unit must shut off during loss of grid, i.e. shouldnt be able to island itself?

Yeah a changeover makes zero sense in this scenario. Changeover to what? It goes down with the grid.

7 hours ago, MuKi said:

4. What is a suitably rated reverse power flow blocking relay?

Depends on inverter brand. In most cases it is simply a kind of energy meter (often modbus, sometimes a current transformer) and the inverter constantly adjusts itself until the energy meter reads zero. Also... it is not a "relay".

7 hours ago, MuKi said:

Off grid setups

You need to register and tell them it is off-grid. They will then send someone to inspect and check that it is indeed off-grid. There is no telling if they have the man-power and/or how soon/often it will happen.

Edited by plonkster
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Could  the experts please give us the sort of switches/breakers we need to install according to this thread.

Some installers I have spoken to do not appear to know and the forum is far ahead of them on requirements!  Could you provide specific web links to these switches etc. so we know exactly what to buy.

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4 hours ago, Mistral said:

Could  the experts please give us the sort of switches/breakers we need to install according to this thread.

As far as I know, a Hager SF263 or an SFH225 or FH240 (25A and 40A equivalents) are perfectly acceptable.

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On 2019/04/13 at 11:24 PM, plonkster said:

It's been moved out to December 2019. If you get it signed off before then, and you don't modify the installation, then it remains legal. From 2020 onwards these inverters will either need recertification, or you won't be able to use them.

Do you perhaps have a link to this extension? 

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I received another picture of what typical micro-grid setups look like to other providers. This is from an ABB presentation.

Selection_198.png.f995eda3429de60d37f5d07c1eca90cf.png

Again, note the absolute hard requirement of something interlocking where the blue line meets the red one. I think that's what the whole thing is about.

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In this scenario i feel it would logical to have an changeover switch as the inverter would be able to backfeed into the grid as it does not know the difference. 

The setups I have seen all have the grid connected to the inverter and the output of the inverter connected to load, so no chance of the inverter feeding back onto the grid. 

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On 2019/04/14 at 12:00 PM, plonkster said:

As far as I know, a Hager SF263 or an SFH225 or FH240 (25A and 40A equivalents) are perfectly acceptable.

Does it not need to be a "centre off" switch, e.g a Hager SFT240?  The SFH225 is not centre off - although the SF263 is.

Edited by admiral
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12 minutes ago, admiral said:

Does it not need to be a "centre off" switch, e.g a Hager SFT240?  The SFH225 is not centre off - although the SF263 is.

Possibly. I just googled some numbers and I was too lazy to go look what is in my own DB.

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