Photovoltaic installation - connection to the grid without selling electricity

Hello,

I am planning an independent construction of a small photovoltaic installation on the roof of the house - approx. 2kWp.
When I read the list of requirements and permits needed to connect such an installation to the power grid (to sell electricity to the grid), I started to wonder if there is an easier way to connect such a power plant to the home power grid - just to save on energy fees purchased from the supplier .

Maybe someone from the forum members will advise - is it possible to carry out such a connection of a PV power plant without permits and contracts with the operator, so that home appliances are powered from the sun (when it is on), and if necessary (when the sun is not shining) to work "in the old way"?

I have read about inverters with the bypass option - they switch to the network in the absence of DC voltage from PV panels - is this the right direction?

I have calculated the average electricity consumption at home and it seems not high (about 0.5kW per hour, i.e. 500W of continuous power). Of course, it is known that there are periods of much greater consumption - kettle, oven, etc.
or just complementing?

Maybe lame questions, but in general, I mean whether my colleagues see any option of connecting a small PV system so that it produces electricity only for its own needs.

Greetings,
Peter

ZE customer contracts do not prohibit this, there is only a point about not sending energy from your own devices to the grid.
And for this it is enough to use the excess production at home. So it's an internal on-grid

Ok, but how do you ensure that this point about "not sending energy from your own devices to the grid" is met?
If I take a "normal" inverter on-grid (they are even plugged into a socket), it may always happen that at a given moment not everything produced by PV will be used up at home and the electricity consumption meter will start spinning backwards
And that is what I would like to avoid.

An inverter with a bypass system (or an ordinary off-grid inverter plus a separate bypass system) would do the trick, but I have no idea how such a system would work at times when the needs of home appliances exceed PV production.

Greetings,
Peter

We had a couple of threads here about the guardian of power.
I use my own invention, you can also buy a ready-made one.

Ah, actually, I saw something called a watt-router or something.
Ok, let me read, it would be the best solution.
On-grid, but without pushing the surplus to the network, only e.g. water heating, etc.

Thanks for the hint.

Wattrouter is cool, but the price is prohibitive - about PLN 1600.

pklawit wrote:

As I read the list of requirements and permits needed to connect such an installation to the power grid

Don't overdo it, there isn't that much of it. You need an inverter that meets the requirements and a signature on the application of the electrician who installed / verified the installation. Are you sure you read about the micro-installation notification and not the connection to the concession?

And what qualifications must the electrician signing such a micro-installation notification for the energy sector have? Typical electrical ones or some special ones for PV assembly?

The second thing is the meter measuring the amount of "pushed" energy to the network - I currently have it
a small recess in the wall with an old mechanical counter with a shield and a micro-panel with 9 screwed fuses.
From what I read, I need to have space to mount this additional meter - does it have to be in the same cavity as the consumption meter?

And how does it connect then - if I connect the inverter output to this additional meter, then nothing from the energy produced will go to power household receivers, but to the network.
Do I get it wrong?

Greetings,
Peter

I recommend reading the drawings at http://pvmonitor.pl/sprzet.php
An exemplary connection is shown in a very good way. It is true that there is a connection for monitoring purposes: one meter counts the entire production from PV, the other meter counts the entire consumption of the house. And the meter for settlements with ZE will be installed by them themselves - between your box and the first security ("S").

Hello

These drawings on the LAN connection of the controller show how to connect what to have information about the production / consumption yourself.
And I mean, what is the connection of the inverter to the network in the context of meters
energy assembled by the power industry.

If I now have one tag energy consumption meter and when connecting micro-installations they install a second one, what does it look like then?
Or like the drawing I scratched out?



Or is it different - they take off the old meter and install a new one, which counts in both directions at once?

Greetings,
Peter

Added after 1 [hours] 2 [minutes]:

I called the supplier (ENEA) and the matter became clear.

No space is needed for an additional counter.
The old counter is disassembled and in its place a new one - two-way is installed.

The gentleman told me that I would have to redo the panel with fuses, because in such a situation fuses (the usual screwed ones) cannot be installed.
Or I have to disassemble everything and install the rail and the "S" fuses on it,
or replace the fuses themselves with such screw-in automatic devices.

Greetings,
Peter

Internal on-grid, overproduction for own use, e.g. by such a waatrouter, as with network synchronization, you can synchronize yourself with an inverter without reporting to the network, or through such a waatrouter, e.g. we do not synchronize with the network

Well, how on-grid is synchro with the network!
ZE has no copyright on the 50Hz waveform phase

I recommend reading http://openenergymonitor.org/emon/mk2/pvmeasurement
It is a project based on pvmonitor.
Generally, it controls (in group) the triac (heaters) so as to balance the energy at the connection with an accuracy of 1Wh.
Load control can be converted to phase or PWM.
Additionally, the system performs a monitoring function.
I made the layout, modified the code a bit for my needs and it flies

I am concerned about the idea of using group control. Cool, because it does not interfere, but the meters probably have a problem with it and do not integrate to zero.

Lesio_Q wrote:

I am concerned about the idea of using group control.

Yeah, some are supposed to work fine. Probably with discs it is without problems in group control.
Phase control and PWM are mercilessly disturbing. So much so that all ds18b20 sensors are crazy. Probably a good rule is to connect such a driver almost on the heater, but will it help?

Many meters have a so-called "sweet zone" ~ 3600J = 1wh.
Within this "buffer" the meter indicates consumption by "flashes" of the diode, but pulses are not counted on the main abacus.
Probably the "primary counter" is bidirectional.
In the pvrouter code, you can freely change the size of the "sweet zone".
Reducing it will improve the stability of the "balance" but will increase the "flicker" effect. PS pvrouter has "AntyFlicker" implemented.

That would be interesting - the LED is blinking, but the pulses are not counted.
How to confirm this on the Polish market of meters ...
My bad experiences with the 'group' ended with the LED blinking, I didn't verify if the meter was counting them

How to confirm - preferably with this system.
It is not complicated - Maga328 + current transformer + voltage transformer (in my case 320-> 2x9V) + 7805 + triac + driver (in my case optoisolated), several resistors and capacitors. You can forgive the radio and send readings to rs232. You can also simulate pv production without an inverter in the software.
The different versions of fw are here: http: //openenergymonitor.org/emon/node/1757
In Rob's videos (links on the same page), the reaction of the dial and electronic counter is shown:
https://www.youtube.com/watch?v=WVqL30uOluQ

It is known that it is generally a prosthesis of dissolution, but you have to live with it until the end of the year Unfortunately, it took several years for the rulers of our beloved country to try to solve what could be solved with the help of the old Pafala.

Well, it is such a wattrouter but you have to do it yourself with electronic components.

What if you were to use an On-Line UPS?

Push energy through the batteries.
This kind of Off-Grid Hybrid Inverter
Takes but does not return