Evaluation of a Single-Phase-Cable simulation model for Line Resonance Analysis

Summary

The interest in diagnostic evaluation of power cables has been steadily growing due to increasing installation length, longer service life and increased ratings for example. The existing diagnostic methods are able to localize failures, if an electrical or mechanical damage exists. Damages are for example short circuits, partial discharges, displaced or broken conductors. However, utilizing commonly available analysis, changes in cable morphology are hard to detect and even more difficult to localize on a position. These changes may include small pinholes leading to the incorporation of water, spreading out in tree like structures or an accelerated aging at a hot spot. The magnitude of these changes can be measured by a loss factor measurement. Unfortunately it is not possible to localize the failure position with a loss factor measurement. A possible detection technic for such failures, that can deliver magnitude and failure location, is the Line-Resonance-Analyse (LIRA). This technology is however not yet completely established. The LIRA is using proprietary algorithms to calculate the failure location and failure magnitude from the input impedance and phase. Input impedance and phase are mainly based on the cable parameter, length, termination impedance and analysis frequency. To obtain more information from the LIRA or its algorithm, it is necessary to understand the function of this technique. In this paper a cable-simulation model that allows calculating the input impedance and phase of a cable with a failure has been used and verified. The cable-model is based on a recent paper, but the verification is for a wider frequency range and the parameters are more detailed.

Additional informations

Authors

Shao Yingbiao, Huang Jinghui