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Most inverters are equipped with anti-islanding feature to prevent the case you are describing OP

You’re asking us to provide a standalone document when there are hundreds of standards spread across lots of disciplines. You’re going to need to be more specific

Both connections are the same. The only time option 2 is used depends on how the equipment is laid out (ie, making sure jumpers are trained properly)

Hello, We have typically been designing large scale PV plants with Y-D-Y GSU's with a NGR on X0. Why not use a Y-D transformer and use novel methods of detecting ground faults (3V0)? I understand that you would need to do a more in depth insulation study because of the larger neutral shift and...

not really much you can do about step potentials at the periphery other than spending needless money to lower the overall GPR below the tolerated step potential.

We wire test switches on both positive and negative side of the relay output contacts only. You don't want to wire a test switch directly inline to the breaker trip coils for obvious reasons. Any testing of the breaker trip circuit needs to be done when the breaker is isolated from the system.

Hi Davidbeach, I understand maintenance mode settings drop the instantaneous setting low temporarily. I was referring to the af levels during normal operation.

I agree with other sentiments that the engineer should provide justification for the setting values. I think it’s worth noting that the instantaneous element of a relay usually isn’t used for mitigating arc flash, but more for protecting equipment from serious damage. Arcing current *usually*...

If the fla of the transformer is higher then 400A, I suppose. But if the allowable GF current is higher it’s much easier to detect and trip/alarm.

Probably when you want the system to run continuously under ground fault conditions, where there are only alarms for ground faults.

Are 2 of the phases "split" and then the 3rd phase is in the middle perhaps?

You’d probably need to make 2 groups of pickup settings that switch whether the gen is on or off.

I assume you’re referring to the amount of traverses for a site. I’ve only seen 2 traverses conducted at different sites, but I could imagine if a site contained a discontinuous soil makeup, more traverses would be a good idea.

I don't think sticking a single line diagram in ETAP (or any computer aided design and analysis program for that matter) will get you very far in learning about electrical power components. If you happen to select the correct component, you would need to then add necessary parameters. This...

Depends. How much unbalance are we talking about?

I agree with the above. It doesn’t seem to be in the best interest of the utility to add a ground further into your system as that would desensitize their relays.

Why would the measured fault current be lower than a through fault? In any case, it doesn’t matter so much the magnitude of the fault, as much as the comparison between the residual current and measured In (3I0). If it’s an external fault, Ig and In would be in phase and wouldn’t operate the...

I do not believe it is required. When calculating step and touch potential formulas at the substation, sometimes a split factor estimation is used for 4 wire distribution lines or transmission lines with OPGW's, which is where pole grounding resistance would come into play. But these are just...

Correct The equipment bonding jumper size for the NGR is not necessarily the same as the neutral conductor to the NGR. It is sized based off NEC 250.36 (G)

I believe the code is referring to NGR let thru current, not continuous rating. Obviously you could plot different cables in a TCC curve and see that you’d probably be able to get by with a smaller cable but the code is code unfortunately.