Either the self-supplied generator cannot be connected to the grid, or the equipment and procedures for connecting to the grid are complicated, making it uneconomical for a small unit.
It is recommended not to connect to the network. Since it is a rural villa, it doesn't matter if the power is out for a period of time, it may be "power outage and back-up". "Supply", that is, the main use is generator energy, and the grid energy is used after the power outage. , wouldn't it be good to have a "nine-wire gate" command?
If you need to connect directly to the grid, there is a photovoltaic inverter produced by the German company SMA that can solve this problem. A grid-connected solar photovoltaic power plant uses photovoltaic modules to convert solar energy into direct current, then reverses the direct current into currentalternating current of 50 Hz, 230/400 volts three-phase or 230 V single-phase via an inverter. The output end of the inverter is connected in parallel with the low voltage end (230/400 volts) of the transformer in the substation via the electrical distribution cabinet to supply the load, and the excess power is sent to the network via the transformer. There is no battery energy storage equipment overall. When there is no sun on rainy days, electricity is supplied to the load from the grid.