Following the introduction of our new External Transfer Switch solution for MultiPlus-II last year, we are pleased to announce that it is now certified for grid-connected applications in multiple countries.
This significantly expands the range of applications for this solution, including ESS.
Ok so what does this mean for the common install?
Asked the same, reply I got:
Die vraag:
Beteken dit nou mens kan enige nie-NRS gesertifiseerde Victron omskakelaar, wettiglik netwerk koppel volgens SSEG reels?
Die antwoord:
Nee, hoewel jy waarskynlik reg is, is hierdie net van toepassing op die MPII groter as 5kVA, m.a.w. die MPII48/8000 en 10000 en 150000.
Dit gesĂŞ sal jy sien die Quattros het ook NRS dokument op die webwerf, volgens Victron gaan hulle op die Kaapstad lys verskyn.
External transfer switch only makes sense when you have inverters in parallel.
Let me use an example. Let’s say you have 4 x 15kVA quattros in parallel. These inverters have 100A transfer switches, so you have a potential maximum current of 400A running through them.
Now imagine there is a grid outage. As it goes with relays/contactors, they are not identical. One of them always moves slower, and therefore takes the brunt of the spark that results when you disconnect. Over time, especially when there are frequent outages, this can result in relay failures. Using an external transfer switch, you can rate the switch/contactor for your application and how often it has to switch. In other words, it allows a more robust installation.
Other advantages include that you can have the transfer switch at the distribution board, and the inverters as far as 20 meters away from there (ie, the transfer switch is “remote”). So you don’t need a thick cable all the way to the “inverter/battery room” and another one coming back. Huge savings on cabling.
You also don’t need a separate bypass switch. You just need a way to pull in the contactor.
And half your paralleling issues (where the paths need to have the same impedance) goes away as well.
In short, this is not for the average home install. This is for a big commercial install.
There is a chance – don’t quite me or press for time or anything, I only heard rumours – that the Multi-RS might get a similar option. And that would make paralleling possible, which is currently not possible.
in Short, SSEG registration requires a central disconnect for multiple inverters even if they have NRS certificates. This device also needs a NRS certificate.
This device falls in that category.
This device is not needed for a single inverter in a residential installation.
Thankfully the Ziehl UFR1001e is already on the list.
If you mean that fitting of a Ziehl makes the older non NRS compliant Victron units compliant then not quite how I read it…? I’d love to be wrong though…
Yes, I saw! Was wondering if typo…?! Does that mean approvals for others (5kVA/8kVA/10kVA MP’s & Quattro’s) on their way?
It’s weird that they aren’t already on the list. The internals of the inverters are mostly identical, the difference between models is pretty much just more/bigger of the same (MOSFETs, Transformers, etc). You don’t send one of each model for testing. You send a representative of the series. If the 15kVA is there, it means the others should be too.
A few things come to mind in this regard…
A Quattro is a Multiplus with two transfer switches instead of one. So it should extend to Multiplus as well (on a technical level, on a red tape letter of the text level, I have no idea).
By the letter of what is written, you could interpret it like that. Technically it would not be sufficient. NRS097 requires two disconnection points (one is allowed to be electronic). The Multiplus/Quattro has only one set, the Ziehl adds a second pair, plus redundant monitoring of at least the passive parameters.
NRS097 requires at least one active anti-islanding measure, but the Multi/Quattro has had that for years already. All that was missing was the paperwork.
For VDE 4510, there has been a grid code that supports the external anti-islanding for many years. The issue was never the hardware, it was always paperwork 
