Investigations on the Effect of the Nozzle Material on the Interruption Capability of a Medium Voltage Load Break Switch

In the process of substituting sulphur hexafluoride in medium voltage load break switches by atmospheric gases, the inferior arc quenching capabilities of possible substitutes have to be compensated. By introducing a polymer nozzle into the switching gap of a load break switch, the interruption capability can be enhanced as the ablated nozzle material changes the composition of the arc plasma. In this contribution the interruption capability of a model load break switch is investigated using different nozzle materials. The results show a good interruption capability when using polypropylene and polyamide 6.6 for high blowing pressures. Polytetrafluorethylene shows good results across a wide blowing pressure range. Polylactide has the lowest interruption capability among the polymers in this work.