Overseas Transformer's

[GoldDigger]

Whether or not a conductor is "neutral" has to do with where it is connected in the system, not whether or not it is grounded. If grounding a phase conductor made it the neutral, corner-grounded delta systems would be even more confusing than they already are. And what about high-impedance-grounded or ungrounded systems? :blink:

FPN: At the neutral point of the system, the vectorial sum of the nominal voltages from all other phases within the system that utilize the neutral, with respect to the neutral point, is zero potential.

(Disclaimer: I did not know any of this until I started frequenting these forums a few months back. Thanks for the lessons, everybody.)

I have a problem with their attempt to rationalize the neutral of a high leg delta with the same rubric that covers the center point of a wye: it is dependent on the way that the phase conductors are used.

The formal definition provides a list, which is fine. The informational note, IMHO, goes off the deep end. Strictly speaking, it means that if you attach a 208 volt load between the high leg and the center tap, the center tap would no longer be a neutral because you would now have to include the 208 volt phase vector in the vector sum.
And it means that if you have a 208Y/120 and you only bring two of the three phase conductors to the service, the center point is no longer a neutral, contrary to the list in the formal definition.

Sometimes it is better just to rely on using a list and not try to justify it in a "simple" way.

 

[fifty60]

I think this question was sort of buried earlier in this thread. I am hoping somebody can elaborate on this topic:

I am reading through some older posts hoping to get a better intuition for the power circuit I am dealing with. Current is indeed flowing from the 230V leg through the load and back to the transformer on the neutral leg. Even though the transformer leg is grounded, the current does not travel to ground at this point, but goes back through the transformer and through the load, and then through the neutral again, and then through the transformer, load, neutral again, of course, switching directions 100 times a second. Is this correct? The 400Y distribution transformer is grounded, and the neutral is connected to this ground, but no current flows to ground unless another conductor in the system is grounded through a ground fault?

The reason for this question was mainly for the secondary of the transformer, but also for the primary. I am trying to understand how the current is flowing through the control circuit, and how the grounded secondary phase is "electrically isolating" the secondary of the transformer, and what happens to the secondary and primary during a ground fault on either side of the transformer.

 

[GoldDigger]

I think this question was sort of buried earlier in this thread. I am hoping somebody can elaborate on this topic:

I am reading through some older posts hoping to get a better intuition for the power circuit I am dealing with. Current is indeed flowing from the 230V leg through the load and back to the transformer on the neutral leg. Even though the transformer leg is grounded, the current does not travel to ground at this point, but goes back through the transformer and through the load, and then through the neutral again, and then through the transformer, load, neutral again, of course, switching directions 100 times a second. Is this correct? The 400Y distribution transformer is grounded, and the neutral is connected to this ground, but no current flows to ground unless another conductor in the system is grounded through a ground fault?

The reason for this question was mainly for the secondary of the transformer, but also for the primary. I am trying to understand how the current is flowing through the control circuit, and how the grounded secondary phase is "electrically isolating" the secondary of the transformer, and what happens to the secondary and primary during a ground fault on either side of the transformer.

This may help: The transformer electrically isolates the secondary wiring from the primary wiring. But once you choose to connect one side of the secondary to the GES, some of that isolation is gone.
You do not have a direct connection between the primary neutral and the secondary neutral, but, as you say, if you connect both of them to the same GES, or even to separated GES networks, you have created a connection between them.

However, there is no reason for current to flow through that neutral-to-neutral connection via the EGC as long as there is no connection (either load or fault) between any non-neutral point on the secondary side and ground.