Wide-frequency measurement of transfer impedance and transfer admittance of shielded cable

The transfer impedance and transfer admittance are two important parameters for expressing numerically the mechanism that allows the passage of electromagnetic energy across the cable shield. Based on the transmission line theory, a simple method is presented to measure the transfer impedance and transfer admittance of the shielded cable in magnitude as well as in phase over the frequency range (0.1 MHz-10 MHz) which covers the main interference frequencies in power system. In order to avoid occurrence of resonance, a shorter cable sample is chosen to carry out the rational results for high frequency measurement. With the proposed method, the test system can be quickly set up and run. A coaxial cable with a braided shield is measured and compared with the existing method, the validity of the method presented in this paper is confirmed. As an extension, the method may be applied to the multi-core shielded cable.