Type of Transmission System

[Besoeker]

In cold climates (Canada, New England), cars can be notoriously hard to start in the winter. Automobile starters run on DC.

However, I am inclined to the opinion that not even the most robust starter motor would like to have 500kV dc stuck up it.....

 

[jdsmith]

When I was a young engineer I worked for a POCO called Public Service Co of Oklahoma which was owned by Central & Southwest (Now called AEP) as a sub-station engineer.

Anyway CSW owned several utilities in TX and we designed a HVDC interconnect with a couple of sister POCO's in TX. It was a bit strange because the HVDS path was only a matter of a few feet in length. Tx is the only state (or at least I think it is) that is not connected to the national grid, and the only legal way to interconnect accross state lines is via HVDC

I believe you are right that Texas is the only state that is segregated like that through DC links. What I remember from power system class was that the vast majority of power transfers in and out of Texas were on the DC links, but that there were some medium voltage lines or some smaller AC circuits that did connect across the border. The AC links that I remember existing were small enough that if you ignored them in your power flow studies that the error was negligible, which is why they are allowed to remain.