Effect of static mechanical strain on the DC conductivity of extruded cross-linked polyethylene cable insulation

DC current measurements were performed on a medium
voltage XLPE cable at voltages from 8.5 to 65 kV
(average field from 2.5 to 19 kV/mm). To assess the effect
of mechanical strain on the conductivity of the insulation,
the cable was wrapped around a tube with an outer
diameter of 110 mm (max strain of 15.4%).
Measurements of the currents through the compressed
and tensioned sections were facilitated by using
longitudinal guards in the insulation screen. No significant
effect of the applied mechanical strain on the conductivity
was found.