Grounding Transformers are designed to provide an artificial, neutral point for ungrounded three phase power systems.
During the line-to-ground faults, grounding transformers provide an easy path to ground faults, thus limit the fault currents and transient over-voltages.
Grounding transformers normally carry short-circuit ground current until the circuit breaker clears the fault. Therefore, they have short time ratings.
The kVA rating of a earthing transformer depends on the normal line-to-neutral voltage and the fault current value for a specified time, such as seconds to minutes.
|Types||Dry or oil-immersed [ZN (Zigzag), ZNyn, YNd(open), Ii0]|
|Voltage||Up to 36 kV|
|Current||Up to 3000 A*|
|Duty (seconds)||10 /30 / 60 or others|
|Frequency||50 Hz / 60 Hz|
|Installation||Indoor / Outdoor|
|Ambient Temperature||-30°C to 55°C*|
|Enclosure Options||Transformer cabinets for any IP degrees with:
- Isolation switch
*Consult factory for higher values.