New Principles for a Safe Interruption of Low Cur- Rents in High-voltage High-rupturing Capacity Fuses

Based on the definition of IEC 60282-1, backup-fuses have to interrupt currents higher than the minimal breaking current. Full-range fuses have to interrupt all currents, which are able to melt the fusing element. Severe circumstances like reduced heat-transfer or external heating might trip the fuse when the actual operating current is below the minimum breaking current or the melting current. In consequence the fuse can explode. Therefore the use of fuses in severe environments with high operating temperatures like fuse canisters and cubicles for electrical switchgears can dramatically aggravate a high risk of failure. Utilizing novel concepts like high-energy materials will enable a defined temperature-dependent tripping of the fuse. Combining this technology with a novel enhanced arc quenching material will lead to an interruption of very low and critical over-currents also in fuse canisters and cubicles under severe thermal conditions.