821 / 2022-04-04 22:17:26

Arcing in AirplusTM, exploring an alternative to SF6 in load break switches

medium voltage,new gases,load break switches

Finding alternatives to SF6 in the modern power grids has been researched ever since it was flagged as one of the gasses with high global warming power (GWP) [1]. One alternative that has shown promising results as a dielectric medium in both gas insulated substations and in load breaking switches (LBS) is called AirPlusTM [2]. It consists of a mixture of synthetic air and a fluroroketone, C5F10O, known as Novec 5110 and was developed by 3M. It is currently used in LBSs rated up to 36 kV [3]. In this work a systematic comparison of the arc voltages and conductivity for free burning and constricted arcs in both gases and the consequences for its further use in switchgear will be presented.



The experiments are conducted in the high current lab of NTNU, which is connected to the 12 kV grid. Direct testing of current breaking for a large set of different currents, voltages, and recovery voltages in different dielectric mediums are possible. The test circuit is illustrated in figure 1 and the pressure vessel is shown in figure 2. The measurement system allows for full range current and voltage measurements. As well as a high resolution of post arc currents that can be present during current interruption. For relevant experiments a travel curve and pressure curve can be measured.