Hydrostatic Pressure Effects on Direct Current Conduction and Charge Transport in Cross‐Linked Polyethene

ABSTRACT

This paper examines the influence of hydrostatic pressure on the direct current (DC) electrical conduction of cross‐linked polyethene (XLPE), a pivotal material for high‐voltage insulation. Experimental measurements were performed on 100 µm XLPE films under hydrostatic pressures ranging from 50 to 500 bar, at temperatures of 30, 45 and 70°C and electric fields from 40 to 280 kV/mm. The results show that the steady‐state current density increases with hydrostatic pressure, as well as with temperature and electric field strength. This pressure‐induced current enhancement suggests a dominance of electronic transport mechanisms within the polymer matrix. To interpret these results, a comparative analysis of conduction models was conducted. While the Schottky emission model was rejected due to inconsistent permittivity extractions, both the space‐charge‐limited current and the Hill‐Adachi models show agreement with the experimental data. Numerical simulations further support the Hill‐Adachi model, providing a physical basis for the observed behaviour. These findings establish a fundamental understanding of pressure effects on XLPE conduction, essential for high‐voltage insulation design under extreme conditions.