Cable insulation optimization - QuickField simulation example
Engineering question
How to find the inner-conductor diameter that minimizes electric stress at the conductor surface in coaxial cable insulation?
Answer
Optimize the conductor diameter while monitoring surface field strength; the minimum occurs near the analytical diameter ratio D/d = e.
Typical applications
high-voltage power cables, coaxial cable structures, cable insulation layers
Download
- Download simulation files (files may be viewed using any QuickField Edition).
Simulation problem
Problem TypePlane-parallel problem of electrostatics.
Geometry
Given
Relative permittivity of PE insulation ε = 2.2;
Cable outer diameter D = 10 cm;
HV conductor diameter dHV = 2 cm (initial value);
Task
Determine the optimal HV conductor diameter dHV for getting minimal electric field stress in the cable insulation at the inner conductor surface.
Solution
Analytical solution states that the ratio D / dHV should be equal to e (2.71828..).
Built-in LabelMover tool is used to perform the optimization. Electric field strength value is measured in the single reference point (labelled as "point") on the HV conductor surface.
Results
LabelMover indicates that the inner conductor diameter should be scaled up 1.834 times (which is 2 cm*1.834 = 3.668 cm)
The calculated ratio of outer to inner diameter is 10 cm / 3.668 cm = 2.726 (close enough
to the analytical result 2.718).
Electric field stress distribution in the insulation with optimal HV conductor dimensions is shown below
Video
- Cable insulation optimization. Watch on YouTube
- View simulation report in PDF