RFQ 800.336.5786

Grounding Transformer General Information

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

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

Zig-Zag (left) Two-winding (right) configurations

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 grounding transformer, Olsun Electrics requires certain application and system data. Please take a brief moment and use the “Check List” below to gather the following (10) basic pieces of 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. Impedance required (percentage or ohmic value per phase)
  6. X/R ratio required (typically a value > 4)
  7. Indoor or Outdoor and special conditions, i.e. 2000 MASL, etc.
  8. Enclosure construction preference (ex. high security compartmentalized padmount, standard ventilated or substation design, special paint color, etc.
  9. Terminal/connectivity preferences, i.e. dead front, live front conventional terminals, etc.
  10. Transformer temperature rise, 150° C if not specified

NOTE! You may have noticed that “kVA” is not one of the parameters requested. Grounding 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 grounding transformer in the conventional sense is to be “labeled” based on the system continuous current and fault current it is designed to carry.

Now you are ready to request a quote!