Detectability of junctions of underground electrical cables with a ground penetrating radar: Electromagnetic simulation and experimental measurements

Abstract : For electricity distribution companies, being able to accurately detect the position of buried power cables using nondestructive methods is a crucial issue. The most important issue is the localization of the junction part linking the cables to each other where most maintenance operations are carried out. In this work we have conducted a feasibility study to confirm the relevance of high frequency Ground Penetrating Radar (GPR) to detect these buried junctions in their environment despite the clutter. The cables are buried in an inhomogeneous Earth medium at about one meter deep. Consequently, we have optimized a folded bowtie antenna to fit the frequency band [0.5 GHz–3 GHz]. Then a rigorous model of the cable is considered in the numerical study using the optimized antenna in a bi-static configuration. A full wave electromagnetic simulation software (CST MWS) has been used to study the detectability of the junction within dry and wet homogeneous sands then a classical Kirchhoff migration technique has been used to process the data and localize the junction. Finally, our analysis has been validated by measurements at a test site (real environment) to show the efficiency of the proposed analysis. The measured data are also post-processed using a digital filtering technique for clutter reduction and visibility enhancement of the buried cable.