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Underground cable crossing

QuickField simulation example

There are two single-phase cables crossing underground at different levels. Similar cable construction simulated in High voltage cable ampacity example.

Problem Type
3D problem of heat transfer.

Geometry
Underground cable crossing There are two single-phase cables crossing underground at different levels. Soil Air, T=+20°C 550 mm 100 1 kA 1 kA

Given
Rated current: 1 kA
Aluminum conductor Joule heating power: 21.4 W per 1 meter of length.
Copper shield Joule heating power: 24.5 W per 1 meter of length.
Thermal conductivity of soil: 0.63 W/(m·K);
Thermal conductivity of aluminum: 200 W/(m·K);
Thermal conductivity of copper: 380 W/(m·K);
Ambient air: temperature T = 20°C, convection coefficient 10 W/K-m²,

Task
Calculate the temperature profile in the soil and cable conductor temperature.

Solution
In QuickField we specify the volume power density, which is Joule heating power per 1 meter of length [W/m] divided by the conductor cross-section area [m²].
The geometry model features symmetry, which allows reducing simulation domain.

Results
Temperature distribution in the soil and cables. Upper cable conductor temperature is 81°C. Bottom cable conductor temperature is 86°C.
Underground cables crossing