Grounding Transformer Vs NRG in the neutral of a equipment

[NickParker]

What are the pros and cons of HRG connected to neutral of a Generator(s) or Transformer(s) Vs Grounding Transformer connected to the MV switchgear bus?
This is with considering that only one NGR is connected to the system incase of parallel generators.

 

[dpc]

This is going to depend on the overall system one-line, protection and coordination requirements, and how the generator is operated. The generator and transformer (if wye) already have a neutral point available. To establish a low resistance ground, a NGR can be directly connected to the neutral point. For high-resistance grounding, generally a single-phase distribution transformer is used to transformer the resistance, but same principle. To ground at the switchgear, you would have to use a more costly grounding transformer, either a zig-zag autotransformer or a two-winding delta-wye transformer.