NOVEL TECHNIQUE FOR PROTECTION OF DC POWER-SUPPLIES AGAINST OVERLOAD AND SHORT-CIRCUIT FAULTS

Protection against over-load/short circuit conditions is of paramount importance in power systems. Present day protection topologies employi ng different techniques have invariably one main drawback in that the fault current reaches the set value before action is initiated to trip the system. This paper proposes a method wherein the slope (or rate o f rise) of the fault current is detected at regular intervals. Once th e slope exceeds the set reference, action is initiated to trip the sys tem much before the fault current reaches dangerous levels. The method provides a fast means of detection of overload and short circuit curr ents and reduces stresses in the systems.