I'm doing a practice test and for some HV trans. line it lists only 0.05 ohm /km (0.08ohm/mile). Is that anywhere near right ? I'm used to little tiny wires with maybe a DCR of 0.018ohm/meter (0.006ohm/ft) for AWG18 for example.
Need to know the diameter and material of the HV transmission line. Keep in mind that at 60 Hz, the skin depth of copper is 8.43 mm, or about 1/3 inch. This means that 67% of the current is carried in the outermost 1/3 inch of the cable. So just measuring, or through analysis coming up with the DCR may not mean much.I'm doing a practice test and for some HV trans. line it lists only 0.05 ohm /km (0.08ohm/mile). Is that anywhere near right ? I'm used to little tiny wires with maybe a DCR of 0.018ohm/meter (0.006ohm/ft) for AWG18 for example.
Yes, that is a good approximation of reality. It's rather deceptive when you look way up at high tension lines, just how thick those conductors are!I'm doing a practice test and for some HV trans. line it lists only 0.05 ohm /km (0.08ohm/mile). Is that anywhere near right ? I'm used to little tiny wires with maybe a DCR of 0.018ohm/meter (0.006ohm/ft) for AWG18 for example.
That's super low indeed.Yes, that is a good approximation of reality. It's rather deceptive when you look way up at high tension lines, just how thick those conductors are!
I think if you do the math, you'll find that the reactive losses - those due to the inductance of the cables - is highers than the I^2*R losses. That's one of reasons some new transmission lines are DC. Even with the losses of converting from AC to DC, then back to AC, the overall efficiencies are higher than if the line was AC.That's super low indeed.
Wait a minute so a 200km stretch of wire is 10 Ohm, and if its 500A(rms), it really does loose 2.5MW, I just fooled myself into thinking is was only 2.5kW, but it really is 2.5MW
by Aaron Carman
by Jake Hertz
by Jake Hertz
by Jake Hertz