A Unified Method for Length Evaluation and Fault Locating of Branch Coaxial Cable Based on S-Parameters Measurements

In this article, a unified method for fault locating and length measurement of the branch cable is proposed. First, typical two-port equivalent networks are extracted by means of a topology analysis of the branch cable, and their scattering parameters (S-parameters) are adopted to achieve the proposed method, due to their excellent performance on characterizing the wave propagation. Then, taking advantage of the inherent relation of the elements in the S-parameters matrix, the analytical formulae for evaluating the branch length and identifying the fault location in a branch cable are derived. This method is simple but effective and appears to be promising for real applications. Moreover, the proposed method is proved to be bound to identify the real fault location without ambiguity. In order to validate this method, some experiments with RG-59 cables are carried out and the accuracy of the proposed method is analyzed. Theory and examples also show its robustness against the fault impedance and terminations.