Voltage sag mitigation by current limiting fuses

More than 50% of the power quality issues are related with voltage sags and interruptions. Equipment manufacturers or manufacturer associations give the voltage sag equipment susceptibility. The curves approximately follow the equation /spl int/v/sup 2/dt=constant, relating this concept to the specific energy of the current-limiting fuses. The upstream impedance determines the relationship between voltage and current integrals. There are several fuse types, which allows the best selection to be made for the voltage sag duration mitigation, using the fuse energy control characteristic. Also the effect of protected system particularities, such as motor starts, transformer connections and hot-cold load pickup can be considered.