ABSTRACT
A transmission line is a four-terminal passive, linear and bilateral network that can be represented by ABCD parameters. ABCD constants provide a straightforward means of writing equations in a more concise form and are very convenient in problems involving network reduction. The model used to calculate voltages, currents and power flows depends on the length of the line. Representation of transmission line by A–D parameters using circuit parameters and voltage and current relations is a means to calculate performance of transmission line is covered in this chapter. The circuit parameters and voltage and current relations can be developed for “short”, “medium” and “long” lines. The long transmission line equations are valid for a line of any length. The approximations for the short and medium length lines make analysis easier. These are required for performance measurement of transmission line. Circle diagrams are used because of their instructional value in showing the maximum power which can be transmitted by a line and also in showing the effect of the power factor of the load or the addition of capacitors. In this chapter aforesaid points are presented.
