Impact of mechanical substrate properties on electrical strength of wrinkle-structured interfaces

Inhalt:
Reaching a carbon-free economy requires the energy transition, which is mainly driven by the electricity generation of renewables and the exchange of fossil energy sources to electricity-based mobility or heat generation. The resulting increased electrical power consumption requires an ongoing expansion of the electrical grid in general, which also needs enhanced component performance of joints, bushings and terminations with electrical potential separation. The dielectric strength of cable accessories depends on remaining cavities at interfaces of the insulating material, where the material’s surface roughness and assembly defects during on-site cable installation are crucial for its enhanced lifespan. The surface structuring based on a wrinkle-formation process introduces controlled, regular patterning on silicone-based insulating material, which retards the discharge initiated at the cavities extending the electron trajectory along the interfaces. Previous studies show a clear tendency towards higher breakdown (BD) voltages for reduced wrinkle-controlled cavity sizes. Different mechanical silicone properties, using adjusted component ratios, additionally affect the resulting compressed cavity size with a clear tendency towards higher BD values of 56.9 ± 2.3 kV for a softer 20:1 ratio compared to 45.9 ± 2.4 kV for a stiffer 10:1 ratio. Accompanying electric field simulations using enclosed cavity profiles show lower E-field magnitudes for uncompressed and compressed wrinkle structures compared to triangular or rough reference structures, reflecting the delayed onset of the ionization process with higher BD values.