A Pure Pulse Voltage-Based Method for Broadband Impedance Spectrum Measurement of Cables

The application of broadband impedance spectrum (BIS) has become a high-performance method for localizing minor defects within cables. The primary focus of BIS research has been on improving algorithms for analyzing the spectrum, with less attention given to its acquisition. BIS is typically obtained using frequency-sweeping impedance analyzers (IAs) or vector network analyzers (VNAs), which are often costly. In contrast to frequency-sweeping acquisition methods, this article proposes a cost-effective, pulse voltage-based method to acquire the BIS of cables by relying exclusively on measuring time-domain pulse voltages, without measuring current, under two configurations: with the cable connected to the acquisition system and with it disconnected. To enhance its applicability in practical scenarios, two correction methods are proposed to mitigate the influence of both external extension cables and internal connection cables. The experimental results demonstrate that the proposed method reliably acquires BIS of cables, with a normalized root mean square error (NRMSE) of less than 3% compared with the results obtained by the impedance analyzer.