A Estimation Method of Subsegment Attenuation Coefficient of Power Cables Based on TLS-ESPRIT in Frequency Domain Reflection

In the past work, the frequency, phase, and amplitude of the cable transfer function (CTF) number are widely used to detect cable defects, but the attenuation coefficient is ignored. Theoretically, each attenuation factor in the CTF is one of the important parameters that characterize the insulation state of the power cable in the corresponding subsegment. Thus, this article presents a method to estimate the attenuation coefficients in CTF based on the total least squares (TLSs) estimating signal parameter via rotational invariance techniques (ESPRITs). First, the CTF is obtained by conventional frequency domain reflection (FDR) and the location of the defect or joint is obtained. The cable is then divided into multiple subsegments based on the location of the defect or joint, and the attenuation coefficient of each subsegment in the CTF is estimated by ESPRIT. In theory, ESPRIT maps the real part of the CTF into an orthogonal subspace to separate signal and noise. Therefore, the estimated value of the attenuation coefficient is highly accurate and reliable. Finally, the effectiveness and practicability of the proposed method are verified by simulation and field test of 32 kV/2.6 km distribution cable.