Could somebody please explain power factor to me, and how to achieve what the DNO has demanded.
I have a multiplus 2 8000, 24 panels totalling 12.6kWp, and a 16kW Seplos battery, and an agreed export of 6.4kW from the DNO, they have stipulated I must have a power factor of 0.95, I am not sure what this means.
Any help here would be appreciated, please see image below.
A few assumptions. You have a contract in place to sell energy back to the grid. Your grid tie inverter GTI (PV inverter) is DNO approved. You don’t intend to send energy back to the grid with the MultiPlus-II, at night for example.
It’s easy to get bogged down in the detail with terms like power factor. The short version is that if your GTI is approved, it will likely meet the PF requirement. It is nothing to do with the MultiPlus-II
The MP will need to talk to the GTI to ensure that you do not exceed the export. This will typically occur in the summer when the battery is fully charged and the sun is giving plenty of energy. If you need to adjust the GTI to meet 2.2.3, you’ll need to tweak the GTI settings.
The MP could talk to the GTI, but the much easier solution is to use the current transformer CT supplied with the GTI, installing the CT closest to the utility meter.
Thanks for reply, i dont have a PV inverter, everything is done on the DC side through a couple of MPPT’s, they charge the battery, all connected to a Lynx distributor that is then connected to the MP2 .
See diagrams
I’ve no experience on configuring the MP for throttling the solar power on the DC side. I can’t see anything in the ESS setup. Your dealer should be able to advise you.
The inverter is already limited to 6,4kW, which is what the DNO has allowed me to export, and there are several other configurations in the setup I can make to essentially make the system G100 compliant (although it wont officially be G100 compliant), DNO may or may not accept this route (external G100 limiters would be needed if not), but my original question referes to the power factor, are you saying that if I have an export agreement of 6.4kW from the DNO, and they require a PF of .95, then I have to throttle the export to 95% of the agreed 6.4kW.
I am still a little unsure what the power factor is, and why I need it at 0.95
No you don’t need to throttle the feedback to 95%.
Put simply, power factor refers to the ratio of power absorbed/used by the load verses the power being fed to it. (The difference between kW and kVa).
It needs to be at 95% so the grid doesn’t have to compensate for anything. Anything below that is poor power factor and ideally would now need power factor correction.
Likely 6.4kw with a .95 PF is 6.7kVa
Some grid tied inverters can be programmed to be leading or lagging.
Ok, so the multiplus I am using is a Multiplus2 8000kVa, but its rated at 6.4kW, that would seem like a bad PF ?, and not reaching the .95 that the DNO has specified, would that be a correct statement, It would seem strange for Victron to design an inverter in such a poor way ?
“On a side note, the Victron synchronises to grid so it would be (technically) what the grid is in phase angle.”
So are you saying that the Victron MP2 compensates to account for a bad PF ?
Still learning all this stuff so excuse me if i am not understanding correctly
Just realising how not easy power factor is to explain.
Efficiency and power factor are not the same thing. Any inverter that claims that its 8kw and 8kVa are the same are talkig utter nonsense.
The inverter is synchronised to grid. (There is a grid code to choose when you set up ESS) Some inverters like fronius can alter the power factor but how it is done affects grid stability.
I didn’t see a G100 in the gird codes in demo mode in ve config Not that I know the regs there. The G99 shows a fixed cos phi of 1. Not editable. So technically unity. Better than the .95
You don’t need to throttle the power on the DC, its automatic. Batteries will only draw what they need to charge, and the inverter will only pull what it needs, whether that be house load, or grid export. The system takes care of the PV side of things.
Ok, so essentially, the system will automatically fall into a good PF by self regulating, I wonder why the DNO stated a PF of .95, rather than a PF of 1, which would I would have thought been better, or more efficient ?
I did see this in some documentation which suggests the MP2 has a PF of 1
The MP2 has a PF of 0.6. Its transformer design makes it that way. Hence the 6.4kw form an 8kVa.
That is different to the power factor to/of the grid though.
Ok, so how am I able to show to the DNO that the system will fall within the 0.95 PF that they have demanded, do you know of any official documentation that can show that ?
Yes the [certificates page here]. Look for the g98 99 certificates in the list. The cos phi is 1.(MultiPlus-II - Victron Energy).
Great stuff, thanks, I can send this to the DNO, although they have specifically mentioned 0,95 PF, but 1 should be better, I am assuming they should accept a PF of 1 if I present the documents to show that, rather than the 0.95.
What they have stated
I assume so too. As i said before not totally familiar with the paperwork system there.
As an FYI in case it comes up. Not that this will likely be an issue for you. But there is a way to limit feedback in the GX menu here.
And my statement earlier is misleading i apologise. You requirements are in kVa (on your first post) so at .95 PF you would be feeding in less in value in wattage. (6400watts)
I’m glad my G99 (with UKPN) wasn’t complicated like NGED has made it.
I applied for 11.68kW, there is a section on form a1.1 where I had to specify the generating equipment, and I just stated a power factor of 1 for each inverter, and that was accepted.
I am glad i dont live there. It seems like the regs change more often than some people change their underwear.
Installation regs do change and evolve like all things, sometimes for the better sometimes they are a pain, sometimes just plain weird.
Getting export permission can also be complicated, some network operators make it straight forward & easy, others complicate things. A lot of problems with this country are related to red tape and BS.
