Grid tied such a waste during load shedding

[KobusK]

Has anoyne found a way to trick a Grid tie inverter to work during load shedding?

I know the GTI must switch off when there is no grid but its such a waist

[___]

Yes. Tie it to the output of a Victron Multiplus.

Seriously, you have to remember that a PV inverter will constantly try to shift the frequency, usually by injecting a tiny bit of reactive power (current leads the voltage). Doing this generally increases the frequency unless there is something on the other end that represents a sufficiently large "weight" to drag it down again. So whatever you use to "trick" it into working must have some electrical weight to it, that is, it is generally an inverter of the same size as the PV-inverter.

Here is a good video (quite long!), including some info on this. See from 29 minutes onwards (35:45 if you're really in a hurry). The entire thing is very interesting, if you have the time for it!

[KobusK]

Very interesting video thanks a million. 

Looking at my current Axpert Hybrid and Solis GTi with youre suggestion  I might as well just replace the Solis with a Victron🥴

[SilverNodashi]

On 2019/03/21 at 9:16 PM, KobusK said:

Very interesting video thanks a million. 

Looking at my current Axpert Hybrid and Solis GTi with youre suggestion  I might as well just replace the Solis with a Victron🥴

I wonder if CoCT will accept this?

[Guest]

2 hours ago, SilverNodashi said:

I wonder if CoCT will accept this?

If the Solis GTi is on the list (did not check) and the Axpert installed as a UPS I cannot see any problem.

CoC for all the connections (Axpert UPS connection) with the Solis GTi having the Engineering sign off too.

Solis itself and Axpert itself combined may be cheaper than a Victron kit. 
It is the manual changeover of the UPS that kills it for me, when Eskom goes off.

[SilverNodashi]

57 minutes ago, The Terrible Triplett said:

If the Solis GTi is on the list (did not check) and the Axpert installed as a UPS I cannot see any problem.

CoC for all the connections (Axpert UPS connection) with the Solis GTi having the Engineering sign off too.

Solis itself and Axpert itself combined may be cheaper than a Victron kit. 
It is the manual changeover of the UPS that kills it for me, when Eskom goes off.

Solis is on the list. 

[Guest]

45 minutes ago, SilverNodashi said:

Solis is on the list. 

It is, I meant to say if the MODEL of the Solis bought, is on the list ... just check for in case a newer model comes out that is not on "the list".

[KobusK]

Gents.

 

What list are you referring to?

[KobusK]

23 hours ago, The Terrible Triplett said:

 Solis itself and Axpert itself combined may be cheaper than a Victron kit. 
It is the manual changeover of the UPS that kills it for me, when Eskom goes off.

Hi Terrible Triplet, what do you mean with this statement? 

Are you saying the Axpert can “kickstart “ the solis? 

Or just by using them together and when the power goes out the Axpert will be the only working inverter, I guess this is what you mean

[Dex_]

are you saying your axpert inverter doesnt work when there is no grid input but you have storage?

[Zombie]

9 hours ago, KobusK said:

Gents.

 

What list are you referring to?

City of CapeTown has drawn up a list of inverters that they have approved for installation/use.

[___]

If you use a Solis with an Axpert, then your PV power is grid-tied and goes down when the grid goes down. In other words, if the power fails during daytime, you run purely from battery and your PV panels stops working.

It's an excellent way to get a legal SSEG installation (because you don't even have to tell them about the Axpert... it is not part of the embedded generation), but it is a rather limiting solution in the face of load-shedding.

Some have proposed a changeover mechanism that moves the PV to the inverter when the grid is down. This same mechanism must also disconnect the AC-input on the Axpert at the same time that it moves the PV panels across.

It's all stupid of course but we've said that a few times already.

[SilverNodashi]

26 minutes ago, plonkster said:

If you use a Solis with an Axpert, then your PV power is grid-tied and goes down when the grid goes down. In other words, if the power fails during daytime, you run purely from battery and your PV panels stops working.

It's an excellent way to get a legal SSEG installation (because you don't even have to tell them about the Axpert... it is not part of the embedded generation), but it is a rather limiting solution in the face of load-shedding.

Some have proposed a changeover mechanism that moves the PV to the inverter when the grid is down. This same mechanism must also disconnect the AC-input on the Axpert at the same time that it moves the PV panels across.

It's all stupid of course but we've said that a few times already.

True, but since load shedding generally only last a few hours it's better than nothing. 

But this then brings the argument back to installing an inverter which is on the list if load shedding during the day prolongs. 

[___]

1 minute ago, SilverNodashi said:

But this then brings the argument back to installing an inverter which is on the list if load shedding during the day prolongs. 

Remember that presently we're still waiting for clarity on the "separate interlocked islanding" device, so even the approved hybrid inverters have a question mark hanging. I will however say this: That if you use a Multiplus instead of an Axpert, you can tie the Solis to the output. It will sign off and your PV modules will work during an outage... at least I hope it will. Now that I think about it, we always have to configure Fronius inverters to Microgrid-50Hz to get them stable... I have no idea what the Solis is going to do

 

[Guest]

19 hours ago, KobusK said:

Hi Terrible Triplet, what do you mean with this statement? 

Are you saying the Axpert can “kickstart “ the solis? 

Or just by using them together and when the power goes out the Axpert will be the only working inverter, I guess this is what you mean

15 hours ago, Dex_ said:

are you saying your axpert inverter doesnt work when there is no grid input but you have storage?

What Plonskter said so eloquently

13 hours ago, plonkster said:

If you use a Solis with an Axpert, then your PV power is grid-tied and goes down when the grid goes down. In other words, if the power fails during daytime, you run purely from battery and your PV panels stops working.

It's an excellent way to get a legal SSEG installation (because you don't even have to tell them about the Axpert... it is not part of the embedded generation), but it is a rather limiting solution in the face of load-shedding.

 

For me, not a WANT but a NEED:
The panels will work when there is load shedding. 
Batteries will only be used when their is no Eskom or insufficient / no solar production.

[___]

6 minutes ago, The Terrible Triplett said:

The panels will work when there is load shedding. 

Agreed. And there shall be no manual switchover. So that leaves me with just two options. Sort out the present unnecessary discrimination against hybrid inverters, OR AC-tie it to the output of a Multi (which limits me to Fronius or ABB).

[Guest]

3 minutes ago, plonkster said:

Agreed. And there shall be no manual switchover. So that leaves me with just two options. Sort out the present unnecessary discrimination against hybrid inverters, OR AC-tie it to the output of a Multi (which limits me to Fronius or ABB).

Lets sum it up.  

A NEED:
1) The panels shall work when there is load shedding. 
2) Batteries shall only be used when their is no Eskom or insufficient / no solar production.
3) There shall be no manual changeover of any kind whatsoever.
4) There shall be no clever AC-tieing of any kind required as all and any discrimination against approved hybrid inverters will cease.

As decreed by the President of the Western Cape.

[phil.g00]

13 hours ago, plonkster said:

Now that I think about it, we always have to configure Fronius inverters to Microgrid-50Hz to get them stable... I have no idea what the Solis is going to do

That "Micro-grid" setting does something, but obviously it still has to respect frequency shifting and voltage contraints.

My guess is, that the Fronius "Micro-Grid" setting desensitizes the grid limitations with respect to time.

In other words the frequency and voltage window settings are still respected , but the time settings are extended to ride through micro-grid bumps.

Hence the appearance of greater stability.

If so, the Solis has the ability to mimic this as besides country codes, custom times ( up to 9secs) can be set.

So I took a gamble on a Solis in March, destined for the output of a Victron.

Sadly I ran out of time to commission it, so it'll be August before I am back in SA again.

If there is anyone still interested, please remind of this thread and I'll provide feedback.

[Fuenkli]

28 minutes ago, The Terrible Triplett said:

As decreed by the President of the Western Cape

would the Western Cape or the CoCT have the legal authority to allow the engineer signing off the installation to ignore the requirement for a change over switch?

[Dex_]

that makes zero sense, why on earth would pv stop working when grid fails? surely this will only happen if the load is greater than the pv?

[Guest]

1 minute ago, Fuenkli said:

would the Western Cape or the CoCT have the legal authority to allow the engineer signing off the installation to ignore the requirement for a change over switch?

They are ignoring the paid engineers reports as we have pointed out to the DA. 

I will argue that if they ever want to fine me when I have a CoC and a Engineers report, pointing out their flaws.

[Guest]

Just now, Dex_ said:

that makes zero sense, why on earth would pv stop working when grid fails? surely this will only happen if the load is greater than the pv?

That is how grid tied inverters work. It is a MUST to ensure safety to the people working on the Eskom side.
And that is why there are hybrid inverters, inverters who will still use the panels to power the loads, the always on loads, after having disconnected from Eskom, anti-islanding.

[Fuenkli]

1 hour ago, The Terrible Triplett said:

They are ignoring the paid engineers reports as we have pointed out to the DA

yes I know. But would it be legal if they WOULD except the engineers report. Would the engineer then not risk liability issues under the SANS regulation? 

[Dex_]

1 hour ago, The Terrible Triplett said:

That is how grid tied inverters work. It is a MUST to ensure safety to the people working on the Eskom side.
And that is why there are hybrid inverters, inverters who will still use the panels to power the loads, the always on loads, after having disconnected from Eskom, anti-islanding.

O_O

[Guest]

3 minutes ago, Fuenkli said:

But would it be legal if they WOULD except the engineers report. Would the engineer then not risk liability issues under the SANS regulation? 

I am not a legal expert or even remotely qualified to answer that, so here are my musings on the matter:

A engineer whom is properly qualified will not sign off anything unless s[he] is 100% sure it is safe, and s[he] will make notes ito any deviation ito SANS regulations, to ensure it is clearly noted and stipulated.

Onus is therefor on the owner of the system, if it is switched on and used.

On the other hand, IF the equipment does NOT preform as designed / as per the papers given, as per how the engineer signed it off, then the onus is on the manufacturer.
The engineer only tested that it does do as the papers says it will.
There is talk that into the future, that system will not need a engineering sign-off anymore, as a proper CoC would suffice.

So it would be an argument between officials on the one side using regulations that are ambiguous and a owner of the system on the other side, with papers to prove the install is safe and meets reasonable regulations, arguing the ambigiouness of the local "incorrectly published" regulations.