In areas where an earth point is not readily available or difficult to acquire, a neutral point can be created using an earthing transformer. Earthing transformers, incorporate a zig-zag (interstar) winding feature that is used to achieve the required zero phase impedance stage, providing the desired neutral earthing conditions. Additionally, auxiliary windings are often provided according to auxiliary power supply requirements.
Earthing transformers are typically oil immersed and may be installed outdoors. Earthing points may consist of a direct connection, through an arc-suppression reactor or through a neutral earthing reactor or resistor. In cases where a separate reactor is required to be connected between the neutral and earth transformers, the reactor and the transformer can both be incorporated into the same tank.
Features (ranges from 11kV to 33kV):