AC Breakdown Voltages of PEEK Insulation Used in Subsea Cable Connections

Subsea cable connectors are crucial components in offshore power delivery systems, commonly using a solid-liquid composite insulation system. Unfortunately, limited literature exists on the electrical characterisation of the insulation material polyether ether ketone (PEEK), despite extensive research on liquid and solid insulation materials in high voltage applications. This paper investigates the AC breakdown strength of PEEK immersed in a mineral oil at 20 °C. The results are statistically analysed using both 2-parameter and 3-parameter Weibull distributions, resulting in characteristic breakdown strenghts of 30.79 kV/mm and 30.40 kV/mm, respectively. Additionally, the location of each breakdown event was identified using a self-developed image processing procedure.