Earthing / Ground
Neutral Earthing transformers are usually provided in 3-phase system, which is without neutral and earth fault protection. Neutral Earthing transformer is having zigzag (inters tar) winding to achieve the required zero phase impedance. Also an auxiliary winding can be provided to meet the requirement of auxiliary power supply in these electrical Earthing transformers.
Grounding transformer is used to provide a ground path to either an ungrounded “Y” or a delta connected system and serves
- To limit the magnitude of transient over voltages when re-striking ground faults occurs
- To provide relatively low impedance path to ground, thereby to maintain the system neutral at or near ground potential
- To provide a source of ground fault current during line to ground faults
- To permit the connection of phase to neutral loads is desired
- Capable to withstand a fault current on rated voltage and frequency through the neutral for a time duration of 30 seconds without using neutral grounding resistor and exceeding the temperature.
- Withstand the mechanical and thermal stresses caused by the rated short time current flowing in the windings under fault conditions.