Editing Electric power transmission (section)

===Short line===
The short line approximation is normally used for lines shorter than {{cvt|80|km}}. There, only a series impedance ''Z'' is considered, while ''C'' and ''G'' are ignored. The final result is that A&nbsp;=&nbsp;D&nbsp;=&nbsp;1 per unit, B&nbsp;=&nbsp;Z&nbsp;Ohms, and C&nbsp;=&nbsp;0. The associated transition matrix for this approximation is therefore:
:<math>
\begin{bmatrix}
	V_\mathrm{S}\\
	I_\mathrm{S}\\
\end{bmatrix}
=
\begin{bmatrix}
	1 & Z\\
	0 & 1\\
\end{bmatrix}
\begin{bmatrix}
	V_\mathrm{R}\\
	I_\mathrm{R}\\
\end{bmatrix}
</math>