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

The application of broadband impedance spectrum has become a high-performance method for localizing minor defects within cables. The primary focus of broadband impedance spectrum research has been on improving algorithms for analyzing the spectrum, with less attention given to its acquisition. Broadband impedance spectrum is typically obtained using frequency-sweeping impedance analyzers or vector network analyzers, which are often costly. In contrast to frequency-sweeping acquisition methods, this paper proposes a cost-effective, pulse voltage-based method to acquire the broadband impedance spectrum 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 broadband impedance spectrum of cables, with a normalized root mean square error of less than 3% compared to the results obtained by impedance analyzer.