To develop cost-efficient subsea switchgear for large sea depths, the extinction of arcs under high filling pressures must be understood. In this work, arc-extinction experiments have been performed with a puffer-like contact configuration using nitrogen at different filling pressures as the...

We report on the testing of a 1 m long and 0.5 m wide racetrack coil wound from 4.5 km of MgB2 tape-shaped superconductors with a copper strip soldered to the nickel matrix. The cross-section of the coil corresponds to what is needed for the field windings of a 10 MW direct drive wind turbine...

Thermal expansion and contraction of the impregnation oil (the “mass”) in mass-impregnated non-draining HVDC cables cause the internal pressure to vary greatly during load changes. Pressure drops after load turn-off is a concern since formation of shrinkage cavities may reduce the dielectric...

The internal pressures in the insulation of two 5-m long pieces of a state-of-the art mass-impregnated non-draining subsea cable have been measured under load current cycling at ambient temperatures ranging from 3 to 37 °C. Thermal expansion of the mass gives in some cases rather extreme internal...

The research and development work towards a compact SF₆-free load break switch for the medium voltage range has led to several design proposals. The interruption capability of three different nozzle and gas flow concepts with atmospheric air as the interrupting medium is compared and assessed. The...

Ablation-assisted current interruption is a candidate for improving interruption capability in medium voltage switchgear. In high voltage switchgear, ablation is utilized to achieve high pressures in self-blast circuit breakers. Self-blast switch technology adapted to medium voltage could represent...