Extraction of High-Frequency Power Cable Transmission Characteristics From Impedance Spectroscopy

This study develops a technique to extract the wave propagation properties of power cables from impedance spectroscopy. This method extracts the propagation constant, characteristic impedance, phase velocity, and RLGC Telegrapher's Equation parameters. The current study first proposes an initial method to extract high-frequency cable transmission characteristics by the impedance spectroscopy of open- and short-ended cables. Using this method, the propagation constant and phase velocity can be extracted accurately. However, the initial method is still problematic. The waveform of characteristic impedance is distorted due to the additional impedance of connection wire between measuring devices and the tested cable. Therefore, this study proposes a modified method, which can eliminate the influence of additional impedance and acquire the high-frequency cable transmission characteristics accurately. By obtaining the series impedance from cable geometry parameters and getting the propagation constant from impedance spectroscopy, the modified method can obtain the characteristic impedance by combining the series impedance and the propagation constant. The extraction is demonstrated for a YJV-8.7/15 kV-1*35 XLPE cable in the frequency range 300 kHz-100 MHz.