Ground-to-earth short-circuit currents in energy systems must be around zero or more amperes, resistance between the neutral point of the transformer (or generator) and the earth is limited to a few amperes between the earth phase. As it is not possible to detect the location of the earth fault in the networks fed by the triangular winding, it is possible to ground it on the high resistance either by zig-zag transformer or by open triangle transformer by establishing the artificial neutral point. This provides a ground fault current of several amperes and facilitates detection of the fault location. The neutral point is grounded with high resistance, ensuring uninterrupted operation during the fault and sufficient (usually between 2 and 10 amperes) and fault location is easy to detect.
The approximate short - circuit currents to earth in electrical networks between 240 and 5000 volts are as follows:
Neutral in networks connected directly to the ground: 1000-6000 A
In networks connected to the earth with low resistance, neutral: 100-1000 A
In networks connected to the earth with a high value of neutral resistance: 2-10 A
Neutral in hydroponic (or triangular) cable networks: 0.3-2.8 A / km: 2-10 A