Cable thermal breakdown - QuickField simulation example
The insulation in a DC cable is subjected to both thermal and electric stress at the same time. Defects in insulation may cause a local overheating due to leakage currents. Calculate the electric current in the faulty insulation with a small defective area.
How to find leakage current in defective DC cable insulation?
Answer Typical applications Geometry
Given
Task
Solution
Results
Current density distribution in the insulation close to the thermal defect.
Engineering question
Set up a plane-parallel QuickField DC Conduction problem for defective cable insulation and evaluate leakage current from computed field results.
HV DC cables, defective cable insulation, cable dielectric defects
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Simulation problem
Problem Type
Plane-parallel problem of DC conduction.
Conductor potential U = 10 kV, shield potential U = 0 V.
Insulation temperature T = 80 °C. Hot spot temperatureTmax = 120 °C.
Electric conductivity of insulation σ depends on temperature, as shown on the plot below.
Calculate the electric current in the insulation.
The model depth is taken to be 10 cm, which corresponds to the defect region axial length.
Total leakage current, I
Normal
1.278e-8 A
With defect
1.282e-8 A
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