The simulation gives negative energy production during the night

[André Mermoud]

You have defined an external transformer.

For such a device you have 2 kinds of losses:

- Ohmic-like losses: these are proportionnal to the square of the current (or the power as the voltage is constant).

- Iron loss: this is proportionnal to the grid voltage, therefore constant. This loss remains of course during thre night.

Now in the simulation you have the opportunity of disconnecting the transformer from the grid during not-operating time.

Therefore you can chek whether a HV switch would be profitable, i.e. if its price will be compensated by the saved energy price.