Transmission Line Zero Phase Sequence Impedance
Transmission Line Zero Phase Sequence Impedance
(OP)
In Australia there are large salt lakes. I am modelling a transmission line which runs on a low causeway built through the middle of one. Does any one have measured or calculated values of earth resistivity for such an environment. Values in Ohm metre are prefered.






RE: Transmission Line Zero Phase Sequence Impedance
RE: Transmission Line Zero Phase Sequence Impedance
RE: Transmission Line Zero Phase Sequence Impedance
For a typical 115 kV vertical construction Drake conductor line, I calculate the following zero-sequence impedances:
rho R0 X0
(ohm-m) (ohm/km) (ohm/km)
0.01 0.250 1.189
0.1 0.257 1.441
1 0.272 1.690
10 0.294 1.935
100 0.323 2.178
Fault values are only partially dependent on the zero-sequence impedance, so this makes the overall result even less sensitive to resistivity. If the entire line is on the causeway, you should probably assume something low if you are concerned mostly with maximum fault levels. The current will not flow entirely in the salt water, so based on the graphs Cuky provided, I'd probably pick a resistivity of 1 ohm-m.