Grounding Bank

[bettsba]

I have a 34.5 kV line that runs a long way in an ungrounded wye configuration. There is no neutral, untill it reaches a substation that consists of a few sets of air break switches, a recloser, and a grounding bank of transformers. I do not understand how the grounding bank (which I assume is a set of transformers that connects the neutral through the windings to ground) reduces neutral impedance, or if that is even its purpose. This seems like it would add impedance to the grounding system.... Can anyone help clarify this for me? Any feedback would be greatly appreciated.

Brian

 

[shirui]

Ground transformer is used to provide a source of ground fault current during line to ground faults, limit the magnitude of transient overvoltage when restriking ground fault occurs and permit the connection of phase to neutral load. There are several type of ground transformer such as Zig-zag and grounded neutral wye delta. They provide low impedance path for zero sequence current during unbalanced fault but present a high impedance for three phase load current. It is easy to find related information about ground transformer by seaching on the internet