Effect of Reflection Waves on Polyphase Non-Uniform Power Line Carrier Channels: A New Propagation Matrix Model

A new matrix model is presented for the study of the voltage and current waves propagation on lossy, non-uniform, polyphase transmission lines. The transmission system is composed of sub-systems in which there are present discontinuities due to junctions of different line sections, phase transpositions, terminal loads. At every discontinuity the reflected (backward) and transmitted waves are computed as functions of the incident (forward) ones by means of matrix operators. An overall transmission matrix relating the input-output voltages and currents is defined, taking into account the multiple reflections caused by two or more discontinuities. The proposed mathematical model is used to compute the voltage attenuation coefficient of practical coupling connections on non-uniform lines, in a wide range of frequencies. The results obtained offer useful indications for the evaluation of the effects on voltage attenuation produced by the reflected waves, and for the optimal choice of terminal impedances.