Product Description

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.

Please take a brief moment and use the "Check List" below to gather the following (13) basic pieces of Grounding Transformer information:

1. Winding configuration; either Zig Zag or Two Winding.
2. Voltage(s) and BIL; The line-to-line value of the system to which the grounding transformer is to be connected. If a two winding grounding transformer is required, the secondary voltage must be provided as well.
3. Continuous neutral current.
4. System available neutral fault current and duration; example 500 amps for 10 seconds, 4000 amps for 2 seconds.
5. Zero Sequence impedance percentage.
6. Per phase impedance in Ohms.
7. Per phase resistance in Ohms.
8. X/R ratio; typically a value > 4.0.
9. Special application conditions; i.e. 2000 MASL, etc.
10. Enclosure construction or NEMA designation preference; i.e. high security compartmentalized padmounted, standard ventilated or substation design, special paint color, etc.
11. Terminal connectivity preference; i.e. dead front, live front, conventional terminals, etc.
12. Winding material; CU if not specified.
13. Transformer temperature rise; 150° C if not specified.