Is it possible to connect a single-phase inverter so that the current is divided

Question

Hello groupers. I have a question, I'm not an electrical expert. Surely most of you are already familiar with the subject of inverter power and regulations. Recently, I submitted documents to ENEA for connecting my power plant to the grid. To my surprise, I found out that the single-phase...

Spajder_PL · Answer

There is nothing you can do about it (unless you do an off-grid installation, but it usually makes no sense and it's better to buy another inverter). Such an inverter will not connect to the grid.

Auto System Polan · Answer

What if I report it as 3.6 kW and connect 3.6 kW of panels to it?

Spajder_PL · Answer

I just don't know what it's like. There is a chance, because, for example, Tauron (probably other ZE too) counts the power of the panels as the power of the installation ... but I am not sure if they will accept it.

Anonymous · Answer

Although technically possible, in your case the answer is no. I just doubt ZE would accept such a solution. You would probably have to show additional certifications for an inverter that would convert 1F to 3F.

As for the details, you can read here -> https://www.elektroda.pl/rtvforum/topic3486739.html

Spajder_PL · Answer

There is no chance of converting 1 F to 3 F by the inverter, the only chance is that the ZE will take into account the power of the panels and not the inverter ...

Auto System Polan · Answer

So, anyway, I've sunk the investment, even if it passes, the inverter will be used at 1/3 of its capacity. So it's better to sell it and look for something 3F.

hostii · Answer

Definitely yes, but with resale you probably know how it will be , I have a reported Delta 5kW on one phase, but it was 2017

ACCel · Answer

And this inverter is NC RfG certified at all?

You should be able to report it with panels below 3.68kW without any problems, if someone in the table with parameters signs the power limit setting of 3.68kW.

Leon444 · Answer

I sooner expect that the inverter will be rejected by the ZE due to the lack of NC RFG than that it has a maximum power of almost 7kW on the AC side.

kev21 · Answer

Hi,

I have a question regarding the first post, i.e. too much inverter power, why is there a refusal?

I am before buying the equipment and I called ZE (PGE) what do I need to know before buying, whether I should apply for the conditions for connecting the installation, etc. I received information that I do not have to ask for the conditions, but only report (the appropriate application) to them after the installation of the finished system. However, it is often read that the energy company refuses to replace the meter with a bi-directional one because the single-phase inverter is larger than 3.6KW, even yesterday the seller where I would like to buy a 4KW inverter asked "do I have conditions in the ZE for a 4KW 1-phase inverter".

I omit the NC RFG standards because only such equipment I take into account, I will do the installation myself, i.e. after installation, the final connection will be made by a licensed electrician (and it was he who warned me about the conditions from PGE before buying anything)

On FV with PGE, I have a contracted power of 11KW, protection 20A.

Thanks

marek_gm · Answer

The limit of 3.68 kW applies to the power in the panels and not in the inverter. Nothing needs to be set in the inverter, no limit, it is enough to show that the sum of the power in the panels does not exceed 3.68 kW. On the other hand, I will add as a curiosity that electric power plants have started to allow the construction of micro-installations with 1-phase inverters, even if the total power is greater than 3.68 kW per phase. However, in this case, there must be a central protection that turns off the entire micro-installation if there is an asymmetry above 3.68 kW. Added after 7 [minutes]: You ask why energy utilities refuse to connect single-phase micro-installations with a capacity of more than 3.68 kW? Because above this power, problems with voltage asymmetry begin, the inverter boosts the voltage too much and the protections start to turn it off. If you have a contractual power of 11 kW, buy either a 3-phase inverter or 3 1-phase inverters and connect panels with a power of no more than 3.68 kW to each.

kev21 · Answer

Ok, thanks for the info, I'm surprised that PGE (even today I was in person and asked if the connection conditions are needed, I got info that no, only the contracted power cannot be exceeded) does not say that the 4KW inverter will be rejected, then I will played with getting rid of equipment for a few thousand

Thanks

ACCel · Answer

An average inverter with a nominal power of 3.6 kW has a maximum power of 4 kW. And in each installation there is no problem for panels with a nominal power of 3.6 kW to exceed this value by 100-200W.

The whole point of this mexican is that there should be no interfacial asymmetry above some value. Suddenly it became 3.68kW, when it was 5kW before (I don't know if I haven't seen 7kW somewhere?). In general, it again looks like lobbying by some manufacturer in the EU, why this value and not the previously used 5kW?

If you already have a 4kW inverter, report it with a power limit of 3.6kW or as a lower model.

marek_gm · Answer

For clarity - the threshold of 3.68 kW applies to the power of the panels and not the inverter. The inverter can have 4 kW, as long as the panels do not exceed 3.68 kW. Added after 3 [minutes]: In fact, Germany has a threshold of 4.68 kW. And that's how it used to be with us. But it turns out that in the rural network, if 4 kW is turned on at the end of the line, there is no chance for the inverter to work, it raises the voltage too much. Germany has a low-voltage network that is largely cabled, and in our country everyone can see what networks we have. Hence the power reduction to 3.68 kW, the network in Poland cannot be compared to the network in the west.

retrofood · Answer

3.68 kW hence 230 V * 16 A = 3.68 kW.

marek_gm · Answer

Way to go. And the earlier 4.60 kW was 20 A.

frank0000000001 · Answer

Can an existing PV installation with an inverter be extended? three-phase e.g. 6 kW by additionally installing an inverter on one phase single-phase (with panels) with a power not exceeding 3.68 kW? So together it would be

frank0000000001 · Answer

As I read, this additional device is to be installed "someday" by the power industry. And applies only to larger micro-installations with a capacity of over 10 kW - the possibility of remote control of active power, and even remote disconnection of micro-installations.
"The new network codes assume the introduction of new certification rules for generating installations connected to the network. In this case, however, a 2-year transition period will be introduced. The intention of the authors of the Polish version of the RfG codes is to prepare for the implementation of the new requirements not only by device manufacturers but also by certification bodies. The new certification requirements will not come into force in their entirety until April 2021. -changes-in-formalities

marek_gm · Answer

Unfortunately you misread. 10 kW is the threshold resulting from the Energy Law. The grid code indicates that a type A module starts at 800 W and ends at 200 kW. Certification is a completely different story, it is a statement of the requirements of the code by performing tests. And in fact, each manufacturer has 2 years to do research. But that doesn't mean the Code doesn't apply today. Of course, the requirement of being able to control the generating module by the OSD must already be met today. The OSD will actually assemble these devices someday, today they are not there, but today when checking what you connected, they may ask where the interface for connecting this device is. If you show them 2 interfaces in two inverters, they may reject the application. I write may because it varies between DSOs, some are already checking, others are just going to.

frank0000000001 · Answer

Since The Grid Code indicates that a type A module starts at 800W, does combining microinverter modules up to 800W into a three-phase assembly, e.g. 2400W, bypass this point?

marek_gm · Answer

NO. I have already written once that a module is a set of production devices in one place. In prosumer facilities, there can be any number of panels, inverters, fans, etc., but it is all one generation module, because it has one connection point to the grid. So the powers add up, the sum must be below 800 W so that the module does not approach the requirements of the code

frank0000000001 · Answer

I read TAURON's requirements of December 31, 2019. In point 9.1 : "Micro installations with installed capacity greater than 10 kW should be equipped with an input port ...which allows ...OSD ...active power limitation....
ENEA also duplicated this point in its requirements.
and I still don't know if the installation up to 10 kW is supposed to have port or not according to RFG ?
My current inverter probably does not have such a port and the microinverters that I want to use in the expansion to 10kW also do not have this port, but they meet the RfG requirements, so how is it?
The fact is point 5 . So there are supposed to be multiple ports? For each generation unit (for each inverter) and the installation as a whole?
In my opinion, when installing up to 10kW, there should be no port either in the inverters or in the installation. Unless I'm wrong.
PS In the case of microinverters, there is no central unit. There are single microinverters that you connect directly to AC and DC, in which case the RS485 port could be in an additional unit monitoring such an entire installation, e.g. EVB300.

marek_gm · Answer

Read point 5 of Tauron's requirements, what the crafting module should be equipped with. Whether they will require it or not, I don't know. In the case of microwave inverters, there is one central unit anyway to collect information from these inverters and which can control them (at least turn them on and off). So this central unit must have RS485 to which the OSD with its device will be connected.

marekm1972 · Answer

I'll stick to the topic because the case is a bit different, but maybe someone knows how they view it (here specifically Energa).
There is a single-phase connection with a power of 4 kW and protection of 20 A, company tariff C (low power to avoid high fixed charges).
It is connected to a working micro PV installation with a panel capacity of 2.72 kWp with a single-phase 3 kW inverter.
On the roof slopes there were 5 panels to the east and 3 to the south, 340 Wp each.
There is still room for 5 panels to the west, i.e. an additional 1.7 kWp, a total of 4.42 kWp and one would like to expand (additional string in parallel with the existing one to the east).
On the one hand, it exceeds the magical 3.68 kW, on the other - the inverter is 3 kW anyway and will not be changed, and on the third - full peak power is practically unattainable due to the east-west arrangement. Can you expand or not?
Logically, it is a single-phase connection anyway, loading it with the full power of 4 kW also causes asymmetry in the network and this is OK (because I pay for this energy), but giving 4 kW is bad ...

prose · Answer

@marekm1972 What counts is the power of the panels, not the inverter in the ZE.

krawietz · Answer

Here I would not be sure what will happen if someone reports 3.6 kW of panels and a single-phase inverter with more power ... Tailor

prose · Answer

I am sure the power of the inverter does not count, at least in Tauron.

msr99 · Answer

It's generally true. The panels will not give more anyway (because as far as I remember it is reported with a plus tolerance). After all, no one will check the number of panels or stickers on the panels. I confirm: they count the power of the panels. They don't care about the inverter. It's an advantage for them.

Is it possible to connect a single-phase inverter so that the current is divided

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