FIELD: electrical engineering; relay protective systems. SUBSTANCE: device has power circuit set up of electrical installation whose phase circuit is connected in series with delta-interconnected current transformers which form differential protective circuit, their number depending on number of electrical installation sides; it also has current circuits and threshold element (relay) provided with equalizing windings with leads 1, 3 and differential (operating) winding with lead 6 all interconnected across leads 2 and 4; device is characterized in that pole leads of current transformers of different phases and sides of electrical installation are connected to one differential relay, and in that differential current circuit of first phase is connected to first lead of first equalizing winding of differential relay, that of second phase, to third lead of second equalizing winding, and of third phase, to sixth lead of differential (operating ) winding of differential relay. EFFECT: simplified design, unified range of relays, reduced labor and time consumed for device adjustment and servicing. 6 dwg
