A method and test bench for evaluating the transfer impedance (Zt) and the transfer admittance (Yt) of shielded cables

摘要

The present invention relates to a method and specific test bench arrangement for measuring the screening effectiveness of cables by the evaluation of the transfer impedance (Zt) and the transfer admittance (Yt). <??>The currents injected in the external screen of cables and the corresponding longitudinal voltages induced in the conductors are, first of all, measured, then a very accurate estimation of Zt and Yt is obtained through the claimed model, starting from an initial approximate value of them, by imposing a good match between the measured and the calculated values of the induced voltages. <??>In the model the coupling between the shield current and the internal conductors is modeled by concentrating the distributed voltage and current sources in lumped voltage and current generators at one end of the line, considering the remaining part as a simple passive transmission line (TL). <IMAGE>