Grounding for generators in parallel

[anbm]

We have (3) outdoor gas turbine generators (480v/3ph, 1MW each)
power a 480v/3ph parallel switchgear also sits outside.

The switchgear is then feeds a step up 480v:5KV transformer,
the output of xfmr connect to an existing underground 5KV feeder
at one end, the other end of this 5KV feeder is powered from utility
as backup source via a MV switch (note: this 5KV feeder feeds
several buildings in the area)

Question: Does nec require to ground the parallel switchgear
above? i.e bond neutral to equipment ground bus
and then connnect to the ground rod, maybe?

All turbine generarors were grounded via a ground wire connect all
generarors and binddto a triad ground rods.

 

[ron]

There is a lot of detail missing and I think without a oneline showing where all the N-G bonds and grounds, grounding electrode conductors and grounding electrodes are, an incomplete answer will be given.

Can you describe or draw this?

 

[tom baker]

And please use the NEC terms instead of the generic "ground", on a drawing or description. Are these generators separately derived?

 

[anbm]

There is a lot of detail missing and I think without a oneline showing where all the N-G bonds and grounds, grounding electrode conductors and grounding electrodes are, an incomplete answer will be given.

Can you describe or draw this?

See attached.

 

[ron]

Since the Gens have N-G bonds, then a N-G bond is not installed at the parallel gear.

The middle gen should be routed to the grounding electrodes directly.

I am surprised that it is 4W+G from the gens to the parallel gear. Typically I would think it is 3W+G, not 4W+G since there is a N-G bond at the gens. Who needs to waste the extra conductors.

 

[anbm]

Since the Gens have N-G bonds, then a N-G bond is not installed at the parallel gear.

The middle gen should be routed to the grounding electrodes directly.

I am surprised that it is 4W+G from the gens to the parallel gear. Typically I would think it is 3W+G, not 4W+G since there is a N-G bond at the gens. Who needs to waste the extra conductors.

Can we not ground the middle generator
as you wrote?