By the way, last time I visited USA, I registered high voltage with 3+N and only 3 wires (connected to the transformers to the consumers network), eg in different parts of CA. What will be the difference, and normal voltages? (Reference to other threads or pages? since this not fits this thread?)
By the way, last time I visited USA, I registered high voltage with 3+N and only 3 wires (connected to the transformers to the consumers network), eg in different parts of CA. What will be the difference, and normal voltages? (Reference to other threads or pages? since this not fits this thread?)
dsk
What are you referring to as "high voltage"?
For voltages in CA, the largest utility is PG&E, & here is a link to the "Greenboook" which lists the voltages they supply.
Huge document, I will need some time to read all that. :-)
This picture http://tinyurl.com/hs7q4wy shows a pole, sometimes the supply has 3 wires, and service neutral, sometimes only the 3 wires. The transformer primary is connected between N and one supply wire, or 2 of the supply wires. What use to be the primary voltage for these transformers?
In California 16kv is very common followed by 12kv, the lines are usually 3 wire on the HV and have no neutral. Transformers are connected L-L or delta. There are some 4 wire lines where the HV neutral is insulated, and those are typically 2.4/4.16kvY.
Outside of California 4 wire is common for the HV with the neutral multi grounded (multi grounded mostly forbidden in California). Typical voltages are 7.2/12.47Y, 7.6/13.2Y, 7.9/13.8kvY, 13.2/23kvY, 14.4/25kvY and 19.9/34.5kvY. 2.4/4.16Y and 4.8/8.36kvY often found on older systems which are now obsolete.