Finite element modeling of direct-buried high-voltage cable ampacity considering dynamic soil thermal properties
Year: 2026
Type: article
Abstract: Traditional ampacity evaluation for direct-buried cables often assumes static soil thermal resistance, which obscures actual operating margins. To address this, a new electromagnetic-thermal coupled finite element model for cross-linked polyethylene (XLPE) cables was developed, incorporating the dynamic thermophysical properties of porous soil. The study quantifies how water content dynamically alters heat transfer. Native soil's thermal conductivity experiences a step mutation, jumping from 0.55 to 1.44 W/(m K) at a 15% percolation threshold. Conversely, backfill sand offers stabler heat transfer, reaching 0.85 W/(m K) at just 5% water content. Simulations of rainfall-to-drying cycles reveal a nonlinear relationship between ampacity and moisture. In supersaturated native soil, ampacity drops locally from 1250 A to 1150 A due to entrapped air. During the drying phase, hydraulic hysteresis disrupts the continuous water network, causing ampacity to plummet to 710 A. Ultimately, this model characterizes dynamic soil thermal resistance under varying hydrological conditions, providing strong theoretical support for evaluating the dynamic transmission potential of underground cable systems.
Source: Scientific Reports
Authors: Jiang Chang, Kun Li, Tianyou Chen, Keru Jiang
Institution: State Grid Corporation of China (China)
Language: English
Subfield: Control and Systems Engineering
Field: Engineering
Domain: Physical Sciences
Open Access status: gold
Estimated APC paid: $2,690
OpenAlex ID: W7164914346