Expanding 1200Wp PV Installation: Combining 3-Phase & Single-Phase Inverters for 4kWp Setup

I'm going to help my cousin expand his PV installation. Now it has 1200 Wp panels of grid. Can a 3-phase and single-phase inverter be used? We want to add installations of about 4 kWp. Will this pass through the Energy Report? Unfortunately, the roof is such that it can't be done on 2 MPPT.

If you do not exceed 3.68 kW per phase and with such power it is unlikely to threaten, then they have nothing to complain about.

Above 3.68kWp 3 phases

Well, a 4kW 3-phase inverter, and a single-phase 1kW inverter for one of the phases?

kamilboski wrote:

well, 4kW 3-phase inverter, and 1kW single-phase to any phase?

To the phase on which it is heavily loaded.

Better yet, connect 2 1ph inverters to the phases with the lowest voltage to avoid shutdowns of the inverters when the voltage in the grid is too high. If the roof is complicated, then inverters with two MPPT, in total, 4 rows of panels can be connected.

Hello, not to start a new topic because this one is about the same topic gloomy.
There is little on the internet about 2 PV installations connected to one meter.
My question is that I currently have PV installations with a total capacity of 6.49 kW (east and south 2MPPT - Sofar Solar 3-phase), wanting to count the warehouse in the fall and recalculating how much I will need in the future for a heat pump, I would like to add a second PV installation in another place on the plot 2-3 kW (190° helm). Probably SofarSolar 3000G3-TL, i.e. a single-phase inverter. I would stick to the phase that is the most loaded (kitchen). As for the formalities, it will be an update with documentation, etc. Do you see any problem here in connecting an additional PV installation. The connected power of the house is 10.5 kW. Of course, I do not want to exceed 10 kW and do it this autumn so as not to enter the new billing system.
Hello, thank you for your answers.

No, only the rated power of added panels or inverter cannot exceed max. single-phase inverter power of your DSO.

Regards

I don't quite understand Mr.
Regards.

Sorry, it was really weird to me the point is that each energy distributor (DSO) has regulations regarding the maximum power of a 1-phase inverter, and it is, from what I remember today, 3.68kW.

Regards

Oh yeah
Yes, but I wrote that from 2 to 3 kW is the max. Even assuming 9.99kW that I would like to have is minus 6.49kW that I already have is 3.5kW is max. And I will rather want to save space on the plot and do it on Longi or DahSolar 6x525Wp.

So it will be ok.

Regards

However, I would consider installing a three-phase inverter, because of this single-phase one you may have problems with the existing three-phase installation. It is about exceeding the voltage value on the phase where it will be connected.

That's why I'm asking, because there are very few topics on this topic on the net.

It is best to view the voltage charts in the application during the largest production. If they are around 250V, it is better not to install a single-phase inverter.

Well, from what I associate are in the very large vicinity of 250 even and so much can be. So what would a single-phase boost on one phase with 5 V? And three phase on each how many V?

Three-phase will distribute the power over 3 phases, and it will not cause asymmetry. And how many volts it depends on the parameters of the network.

I have to start looking for some small 3f inverter because Sofar has 3.3 KTL-X of the smallest 3f.

The power will spread out, but the voltage will not be equal for sure on all phases. So it may be that 3-phase will not be better than 1-phase. Nevertheless, I encourage you to use a 3-phase one because there is a greater chance for more correct network parameters.

Regards

And what can it look like between, for example, installing 2 kW and 3 kW, or with a difference of, for example, 1 kW, the increase in voltage will be significant? 245 V is such a standard in my area for everyone who has PV.

DEFENCE wrote:

I have to start looking for some small 3f inverter because Sofar has 3.3 KTL-X of the smallest 3f.

It will be difficult, because three-phase ones start at 3kW for most manufacturers.

DEFENCE wrote:

And what can it look like between, for example, installing 2 kW and 3 kW, or with a difference of, for example, 1 kW, the increase in voltage will be significant?

The value will not be large, but it may exceed the limit. If you have the opportunity, put on 2kW first, see how it behaves and if there is no problem, you will add an additional kilowatt.

Well, I don't have that option. I import panels on my own from parts of Poland where I get a good price. And this is known shipping costs, so it's best to get the target number of panels. In general, I bet on the 1f inverter all the time. Or maybe someone from the forum has a 1f inverter and will tell you how it raises the voltage, if only on one phase.

But it's not about the inverter, it's about the power grid, the number of PV installations on the perimeter and the energy consumption of consumers.

DEFENCE wrote:

Well, I don't have that option. I import panels on my own from parts of Poland where I get a good price. And this is known shipping costs, so it's best to get the target number of panels. In general, I bet on the 1f inverter all the time. Or maybe someone from the forum has a 1f inverter and will tell you how it raises the voltage, if only on one phase.

Such calculation of the voltage increase requires the power of the installation P, the impedance of the short-circuit loop Z and the voltage in the network U, and if users with PV installations are connected to this network, the voltage measurement should be done on a sunny day.

?U = P x Z / 253

by transforming the above formula, we can also calculate the power of a single-phase installation that can be connected to the network so that the voltage does not increase above 253V

P= (253- U) x 253 / Z

Added after 1 [minutes]:

DEFENCE wrote:

Well, from what I associate are in the very large vicinity of 250, and so much can be. So what would a single-phase boost on one phase with 5 V? And three phase on each how many V?

3 times less

Well, I've already read about the short-circuit loop, etc., but another problem arises that the commune has received funding and more installations will be added to push electricity to the transformer. Plus people who will want to set up private installations before the new year. The network is definitely not prepared for this.
Had it not been for the change in regulations, I would have delayed the construction of the additional installation for the heat pump myself. But you have to hurry and count on improving the network, which will probably happen later than my life ?

Hello, I have a slightly opposite problem - I have an old installation from 2016. 12 Panels 255 W (D6P 255B3A) plus 1 Phase Inverter Solis -3K-2G all this works - but at the current prices of eco-pea coal, I decided to install a 3-phase Panasonic TCAP 9kW heat pump and electricity will be needed on the roof ... Maybe someone will advise how to do? Add 2 inverters, this time 3-phase and 6-7 KW panels (e.g. 15pcs 450W = 6.75 kW) And how to connect it? Are 2 inverters going side by side? 1 phase and 3 phase? What about the voltage on this 1 phase? Or maybe sell the old inverter and fasten the old 12 panels (3.06kW) on the first string of the new inverter and 15 new ones on the second string? (6.75 kW) Please help!

It is best to buy a new three-phase 10kW and connect the old installation to one string, and the new one to the other. Of course, if in the new one these 15 panels will be in the same orientation and at the same angle, and without shading.

Then the inverter will not try to equate the power of the new panels to the level of the old ones - so they will not all work like the 255W ones? Somewhere I heard about my ears but maybe I misunderstood or maybe this phenomenon occurs if we mix panels of different power on one string, it equals ..?

If the panels are on separate circuits (MPPT) they do not affect each other. This situation you write about occurs when various panels are connected in series.

I would go for a new 3 phase inverter. The one that has its phase redirected to the room that consumes the most single-phase electricity.
I would plug the second inverter into 3 phases and let it work like that.
Notice the document on the Photovoltaic Panels channel that the author of the program from Tauron discusses that it will be possible for the energy company to remotely turn off installations above 10kW. Better stay on 2 inverters. Even in the event of a fault, you still feed into the grid and are not in danger of changing your contract. Read the contract that if you do not enter for xx days, the operator may change your contract. And they will probably do it to catch people for the new billing system.
Because