A HV VARISTOR ASSISTED FUSE

摘要

Results of investigations on fuse-to-varistor current commutation has been presented, indicating that a significant reduction in the energy dissipated during a fault current breaking by the fuse can be achieved if the support of a parallel varistor is provided. In the focus of interest are expulsion fuses, which are cheaper and better suited for high voltage operation, because of their possible full range characteristic. The varistor assistance can increase almost infinitely fuse breaking capacity, reduce significantly gas expulsion, permitting even a closed fuse design, and limiting fire hazard. Basic features required for a fuse design to operate with the assistance of a varistor has been discussed for both low and high current faults. Although voltages as high as 1 kV/cm can be generated by fuses with small diameter capillary confinement, in most practical applications, the authors used a half of that value.