Study on 12 kV outdoor vacuum switch with replaceable HRC element drop out fuse

A new type of vacuum interrupter for a 12 kV outdoor vacuum switch was experimentally studied, the envelope of which was made of porcelain with a petticoat flange for outdoor insulation. In order to produce an axial magnetic field and improve the capacity of transfer current in the vacuum interrupter, an iron plate, of a horse-shoe construction design, was chosen as an electrode. The drop-out fuse with a replaceable sand-filled HRC element in series with the vacuum switch is a new design concept to increase breaking capacity. This design form yields a vacuum switch and drop-out type combination fuse.