Creepage Discharge Characteristics of Solid Liquid Interface in Subsea Cable Connectors

Subsea cable connectors are crucial components in offshore power delivery systems. These connectors use both solid and liquid insulation materials, which inevitably creates a solidliquid interface susceptible to creepage discharges. This paper investigates the creepage discharge characteristics on the surface of polyether ether ketone (PEEK) insulation immersed in a synthetic ester liquid under AC stress. The results demonstrate that the creepage process can be effectively divided into two stages, with partial discharge (PD) magnitude and phase resolved PD (PRPD) patterns showing distinct characteristics. During stage one (initiation stage), the PRPD patterns are similar to those observed in an open liquid gap. However, once the experiment enters stage two (propagation stage), a significant reduction in PD magnitude is observed, accompanies by changes in PRPD pattern and clear growth of the surface tracking. Furthermore, the cumulative energy of PDs is compared with the length of surface tracking, exhibiting a strong correlation between them.