Characterization of solid-liquid interface for wet-mate subsea HVDC connectors

Wet-mate connectors are essential components in a submarine HVDC system. Solid-liquid insulation systems play an important role in the electrical insulation performance of a WM chamber. In this paper, the electric field distribution in synthetic ester oil of a solid-oil insulation system is studied by using Kerr electro-optic technique where the measurements were carried out with the presence of moisture and ionic contaminants. Moreover, effect of voltage polarity on the electric field distribution in the oil is investigated. For two solid liquid interface geometries studied, the electric field norm decreases gradually from the ground electrode to the HV electrode under positive DC while it remains almost constant for an applied negative DC voltage. The deviation of magnitudes of electric fields particularly near the electrodes suggests the presence of positive ions in the oil under positive and negative testing conditions.