Im still not seeing the correlation between clearing time and lightning surge currents, surge arrestor operation, low magnitude persistent faults (which would never clear), induced currents or stray NEV.

A low magnitude (high impedance) phase to neutral fault out on the line would never need to clear from a electrocution perspective since the bulk voltage drop will be along the fault itself and not across the phase and MGN as with a low impedance fault. In such a case current across the MGN will typically be less than a few hundred amps magnitude and as such the resulting voltage drop across the MGN will only produce 10s of volts to remote earth.

{Or, another way to view it is that if a fault does not pickup ground settings in a recloser or feeder breaker, or is less than a lateral fuse, it can be likened to worse case load imbalance}

Assuming 1000 ohms hand to foot, a voltage 50 volts or less does not necessitate immediate removal:

Also, not to get too tied up in semantics, but when someone says "system impedance", a power system engineer like myself tends to think Thevenin equivalent impedance of a system and not about the grounding system impedance.

I think this is the root of our debate with any inadvertent befuddlement.

Thevenin equilvalent impedance along with the impedance of each individual component is at least half the picture when dealing with system grounding- often playing a much greater role than grounding system impedance itself.

{In simple/tangible terms is a substation with an 80ka fault current (New Jersey's 230kv system) going to have the same ground grid as a substation with 10ka short circuit current?}

While not limited to just two, these play a major roll:

1) The internal voltage drop of the substation transformer along with its primary source positive sequence impedance.

A fault nearby the substation will result large current flow causing a significant dip in voltage as measured between the X0 and X1 terminals resulting in less voltage to remote earth at the fault. Where as a fault miles out from the substation will result in less current to flow and thus relatively unchanged voltage between X0 and X1. (assume A phase fault in both these scenarios)

2) The voltage divider which forms between the phase conductor and the MGN conductor including all of its parallel paths. A 50/50 impedance will result in half the voltage to remote earth- 3,600 volts to remote earth assuming an infinite supply transformer. 40/60 = 4320 volts to remote earth and 70/30 = 2160 volts to remote earth.

These two factors primarily determine voltage to remote earth.

See comments 3 and 4 above.

Comments 3 and 4 ignore-

1) the potential divider which exists in every fault loop

2) Nothing requires that a ground grid be installed in someone's back yard. Me using an electric grill has me at remote earth.

Please provide references.

Both interconnection and none interconnection is used around the globe:

The only factors I am aware of for bonding the primary neutral to the secondary neutral are those outlined in the NESC. This is the governing standard.

First of all this looks like an IEC standard so its not applicable.

Until one realizes that the NESC and NFPA-70 hail from the IEC. The International Electrotechnical Commission controls, outlines, harmonizes and governs every single code and electrical standard on earth.

Second the physics do not change regardless of what flavor of standard or code is followed.

I'm well aware NESC has decided to forgo table 44.A1 ignoring Uf connecting the MV neutral with the LV neutral shamelessly disregarding RE, RB and RA or the disconnection time of feeder, midline or tap device.

This however does not change Uf, or the physics or outcome of a one size fits all approach.

Second of all, this table looks like it's about the allowable power frequency stress voltage on insulation for equipment.

You asked for an example of where feeder disconnection times may result in separation of MV and LV and I gave one:

Third of all, there is nothing mentioned here about using any of this as criteria to bond the primary neutral to the secondary neutral.

A dozen factors can dictate connection vs separation.

Here is another example- With RE and RB connected, consideration must be given for Uf.

And of course 442.2.3 mentions separation as a means to fulfill requirements.

Sorry but no. Ohms law is very real as it was derived empirically. Also, the imaginary part of impedance is not make believe (despite its name), it actually represents quadrature conduction for reactive elements in AC time- and frequency-domain analysis.

Not sure what you are referring to about with heating coefficients, log equations or feedback

Ohms law doesn't exist in nature. It is purely man made, only created as a comprise to simplify the extraordinarily complex

You really think a 2,400 watt heater drawing 10 amps at 240 volts will draw exactly 8.66 amps at 208 volts? Or a 100 light bulb will measure the same resistance when its cold vs when its lit? If heating coefficients did not matter I would get 144 ohms on a cold light bulb- however we both know that not to be true.

... None of these have anything to do *directly* with ohms law or complex impedance but I understand the point you are trying to make. At the end of the day, all math is theoretical, the difference is whether or not these analytical tools have sound applications and reasonable results/assumptions.

Right, hence why it is necessary to simplify down to lumped impedance like RE, RB, RA, ect.

Going back to the point: Persons/property are not in contact with remote earth, but they may be thought of as being connected to it by some large equivalent impedance.

Right, which does not bring the person to the same potential as the grounding system in the home.

Again, this highly depends on the physical direction the current is traveling and whether or not you or the isolated secondary system happens to be in the fault current path back to the other grounding electrode.

Duration and magnitude as seen in Table A. Interconnecting RE and RB places voltage into the premises wiring due to the potential divider formed between the hot and MGN. 3,600 volts is brought out to the grill, across a 1000 ohm body and in theory a near zero ohms between the person's shoes and the 138kv-12.47kv substation ground grid.

Im not talking about capacitors here. I am referring to the interwinding *capacitance* between primary and secondary windings. Capacitive and transformer action will still transfer potentials from the primary system to the secondary system regardless.

Right, but this is brief, where as a power system fault can produce current lasting many cycles.