Design of power line carrier systems on multitransposed delta transmission lines

It is shown that some of the most widely accepted coupling recommendations for power line carrier (PLC) systems do not prevent modal cancellation. It is also shown that computer system programs for calculating line frequency response may fail to detect model cancellation conditions. A method of PLC system design for multitransposed horizontal and delta transmission lines is proposed. It is based in W.H. Senn´s technique (1976) for calculating PLC frequency responses and allows for the consideration of line data uncertainties and line parameter variations. A technique which makes use of shunt capacitors connected to a few points along the line is also discussed. The risk of modal cancellation is decreased and, in some cases, it can be eliminated