The application of the differential analyser to transients on a distortionless transmission line

The behaviour of a transient on a finite distortionless line can be described in terms of two travelling-wave systems propagated in opposite directions along the line. The voltages in these two waves satisfy two ordinary differential equations depending on the terminal conditions, and involving a relation between the voltage at two times differing by the time of travel of a wave from one end of the line to the other and back. Equations of this type can be handled mechanically by means of the differential analyser, using a special form of input table, and the use of the differential analyser does not require that the terminal impedances should have linear characteristics. The application of the differential analyser to a line with a capacitance at one end and a non-linear resistance (lightning arrester) at the other is discussed in some detail as an example, and specimens of machine solutions, both with a linear and with a non-linear resistance at the far end, are given and discussed, and compared with oscillograms taken on an actual line.