Symmetrical Mutliphase Conductors

Often we only have the zero and positive sequence impedances of conductors. In these cases we construct the phase impedance matrix as:

\[z_{abc} = \begin{bmatrix} z_s & z_m & z_m \\ z_m & z_s & z_m \\ z_m & z_m & z_s \end{bmatrix}\]

where

\[\begin{aligned} z_s &= \frac{1}{3} z_0 + \frac{2}{3} z_1 \\ z_m &= \frac{1}{3} (z_0- z_1) \end{aligned} \]