Challenges of climate neutrality for the external insulation of vacuum interrupter

The need to protect the climate is enshrined in a number of international agreements and national targets. This requires insulation systems in energy technology to be reconsidered. The replacement of previous insulation materials, such as SF6, with climate-neutral insulation materials requires a lower field strength than before. The brazing seams of the climate-neutral vacuum circuit breaker are critical areas for the external insulation system. In order to minimise the local field strength an industrially manufactured vacuum interrupter is equipped with field control elements on the outside. Different variants of field control elements were investigated with lightning impulse voltage to determine the statistical withstand voltage. The results show, that field control elements increase the withstand voltage of vacuum interrupter up to 26 % and so effectively reduce the maximum electric field strength. There is an indication that the flashover process can be influenced by the design of the field control elements. Due to the effective reduction of the field strength the use of climate-neutral insulation materials is feasible.