Investigation of the uncertainty using the line-injection method for the determination of the screening attenuation of high voltage cables

Coaxially designed high voltage (HV) cables, as in use in the power train of an electric vehicle, differ in their characteristics and design from conventional coaxial lines of communications engineering and measurement technique. Anyhow typical system properties as screening attenuation and transfer impedance are important parameters for characterization. Components of power electronics with transient switching operations cause harmonics in the high-voltage system of an electrical vehicle, which show frequency components up to the three-digits-MHz-range. The high-voltage power cables convert to an effective antenna structure depending on length and design. Therefore the need of an adequate screening attenuation and transfer impedance is required. It is questionable how far common measuring methods can be transferred to the new application. Therefore the paper investigates the suitability of the line-injection method for determining these parameters. Basis of assessment is the uncertainty of the obtained measurement results. There is a comparison in measuring the parameters of a conventional coaxial measurement cable (RG214) and a HV cable.