Dielectric Fluid Based Electrical Insulation System for Power Cables in Electric Transport Systems

Exploration of a novel composite electrical insulation system, consisting of dielectric fluid aided by additively manufactured spacers, for high temperature superconducting (HTS) power cables of the power systems of electric aircraft and ships, are discussed. An additively manufactured helical insulator spacer was shown to be effective in maintaining the HTS cable on the axis of a cryostat for a uniform standoff. The helical structure tolerates the thermal contraction during the cooldown. The dielectric fluid was cooled slowly to minimize the formation of air pockets and the associated partial discharge activity. The designs were experimentally tested for both the withstand voltage and partial discharge inception. The cables with dielectric fluid at room temperature and the uniformly frozen dielectric fluid at 77 K showed no partial discharge activity, and the measured withstand voltages up to 24 kV. The spacer materials and design need further exploration to identify suitable materials, shapes, and additive manufacturing methodology to develop effective electrical insulation systems for cryogenically cooled lightweight HTS or hyperconduting power cables for electric transport applications.