Dynamic Assessment of Soil Resistivity for Enhanced Thermal Management of Underground Medium Voltage Cables

This paper presents a thermal assessment of medium voltage buried power cables. A multivariate statistical model is used to estimate soil thermal resistivity based on environmental factors. The thermal electric equivalent model, validated through field measurements, demonstrates how soil thermal resistivity variations reduce cable ampacity by up to 64%. The accuracy of constant average thermal resistivity values and dynamic resistivity values was compared. Incorporating dynamic resistivity significantly improves the accuracy of thermal modeling, reducing the maximum error from 8-10% to less than 1.6%. Coupled thermo hydraulic approach was employed to study soil moisture dynamics, with critical drying effects observed at 30 cm from the cable installation. This research provides valuable insights for optimizing underground cable installations and improving dynamic thermal rating methodologies in power distribution systems.