The PVT series has been specifically developed for solar panel converters and other applications where energy is fed back to the grid.
Many transformers have additional windings on the secondary side to compensate for voltage drop, so that the transformer delivers the correct voltage under full load. They are referred to as compensating windings.
The PVT models do not have this feature, their winding ratio is 1:1. This gives the converter a more accurate picture of the effective voltage on the grid. When energy is fed into the grid via the secondary, the compensating windings will work in the wrong direction, so that the converter will measure an excessively high voltage, leading, at times, to the tripping of the overvoltage protection.
Reversing the transformer so that the compensating windings are on the grid side would result in the converter seeing an excessively low voltage, and limitation would then only be initiated when the grid voltage is already much too high. It should go without saying that this is not permissible!
PVT transformers bear the IRC label indicating that they have a low inrush current. This means they are also suitable for non-industrial electrical installations.