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Grounding Transformer | Ground Isolation Transformer | Neutral Grounding Transformer

Should you have an application where a ground path is required for a delta connected or ungrounded wye connected system and a custom neutral grounding transformer, or ground isolation transformer is required…Olsun Electrics can do that!

Olsun can design, manufacture and supply a dry-type neutral grounding transformer, or ground isolation transformer, in either a Zig Zag or a Two Winding configuration for your particular application.

Zig Zag Transformer Configuration                                          Two Winding Configuration

A properly designed and installed grounding transformer will protect an isolated three phase system in the event of a line-to-ground fault by providing a low impedance path to ground for ground fault currents to flow while prohibiting voltage rise in the un-faulted phases and accommodating the connection of phase-to-neutral loads if required.

To provide a quotation or to design and manufacture your required ground isolation transformer, Olsun Electrics requires certain application and system data.

Please take a brief moment and use the “Check List” below to gather the following (12) 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 in Ohms per phase.
  6. Zero Sequence resistance in Ohms per phase.
  7. X/R ratio; typically a value > 4.0.
  8. Special application conditions; i.e. 2000 MASL, etc.
  9. Enclosure construction or NEMA designation preference; i.e. high security compartmentalized padmounted, standard ventilated or substation design, special paint color, etc.
  10. Terminal connectivity preference; i.e. dead front, live front, conventional terminals, etc.
  11. Winding material; CU if not specified.
  12. Transformer temperature rise; 150° C if not specified.

Now, you are ready to request a quote!

NOTE! You may have noticed that “kVA” is not one of the parameters requested. Grounding isolation transformers are sometimes referenced by a kVA, but technically, they should not be so referenced unless they are providing auxiliary power in some way.

A neutral grounding transformer in the conventional sense is to be “labeled” based on the system continuous current and fault current it is designed to carry.