FIELD: electrical engineering. SUBSTANCE: device is classifying as relay-type directed protection system for electrical net with insulated neutral line with low capacity with respect to equipment capacity under current sensitive protection. Device has current 1 and voltage 2 transformers of zero line connection which first terminals are connected directly but other are connected by phase-shift condenser 3. Protection actuator 4 is connected parallel to current transformer 1 and voltage transformer 2 outputs of zero CIRCUIT. EFFECT: more sensitive protection device for low current short circuit earthing. 1 dwg
