Quote:
"In the Queens power outage thread, it was explained that the NYC grid is designed exactly like gfretwell described, with the secondaries tied together, with no means of disconnect in between. Strikes me as a dangerous situation, too! I'd hope there are egg insulators on the poles and the wires are there only for tension... Though, in theory, there are fuses on the primary side of all the pole pigs which should open if overloaded, right?"
It is dangerous, that's why we don't do it anymore. It's called "underbuilt" (at least it's called that here)and it not only provides more fault current, it allows for backfeeds from one pot to another. VERY dangerous for lineman.
As Scott35 noted, many factors go into fault calculations. Once you get outside the city, many of the distribution lines are #4 ACSR and quite a few older lines are #6 harddrawn. Depending on how far the customer is from the substation, the fault current can drop dramatically in wires like these.
As for core saturation, I thought that was more a factor of high voltage than load.
