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 t...

This paper focuses on the arc voltage measurements of electrical arcs burning inside cylindrical tubes in nitrogen at different filling pressures from atmospheric and up to 80 bar. To investigate the effect of ablation, both nonablating ceramic tubes (alumina) and ablating polytetrafluoroethylene (P...

A supercritical (SC) fluid is formed when both pressure and temperature of a fluid exceed the critical point, where distinct gas and liquid phases no longer exist. SC fluids demonstrate combined properties of gas and liquid, which make them interesting to investigate them as an arc extinction medium...

One type test requirement for medium voltage load break switches is to interrupt 100 consecutive "mainly active loads". A puffer-type switch with axial-blown arc has been tested according to the 630 A/24 kV ratings. The nozzle and contact wear were measured regularly to investigate design ...

A simple gas blow switch consisting of an axisymmetric tulip/pin contact and a cylindrical polytetrafluoroethylene (PTFE) nozzle has been used for empirical studies of medium voltage load current interruption in air. Only the thermal phase of the interruption is considered. Based on the results of m...

Replacing SF₆ with air as the arc quenching medium in switching equipment is favorable from an environmental point of view, but may be technically difficult for compact devices. Medium-voltage load break switches have modest current and voltage ratings, typically 630 A/24 kV, and are thus expected t...