The function of the earthign transformers id to introduce the neutrality poit for those system without the neutrality poit, the neutrality point on the earth through the arc suppression, the windings of the earthing transformer are Z-wiring, and the wiring method has the features as the follows:
low zero sequency impedance；
high excitation impedance；
low power consumption；
In addition, the earthing transformers can used as the station transformer with a secondary winding.。