Reconsider Problem 4.28 with still another alternate phase placement shown below.

Find the inductive reactance of the line in \(\Omega / \mathrm{mi} /\) phase.

Problem 4.28

For the case of double-circuit, bundle-conductor lines, the same method indicated in Problem 4.27 applies with \(r^{\prime}\) replaced by the bundle's GMR in the calculation of the overall GMR.

Now consider a double-circuit configuration shown in Figure 4.36 that belongs to a \(500-\mathrm{kV}\), three-phase line with bundle conductors of three subconductors at \(21 \mathrm{in}\). spacing. The GMR of each subconductor is given to be \(0.0485 \mathrm{ft}\).

Determine the inductive reactance of the line in ohms per mile per phase. You may use

\(\mathrm{X}_{\mathrm{L}}=0.2794 \log \frac{\mathrm{GMD}}{\mathrm{GMR}} \Omega / \mathrm{mi} /\) phase

Phase Placement 1 2 C A Physical Position 3 1' 2' 3' B B A C