FIELD: power supply of industrial enterprises over cable lines of 1000 V and higher. SUBSTANCE: device for frequency-current protection of cable lines incorporates units of equipment at feeding and receiving substations connected by communication line. Each unit includes transceiver of frequency signal and switches and unit at feeding substations has set of overcurrent protection. Communication channel is formed by metal sheath of cable and ground. Device is supplemented with transformers of frequency signal, one of windings of each being connected to transceiver and each other winding being placed into grounding circuit of sheath of cable. Unit of equipment at feeding substation additionally includes logic block. Unit of equipment at receiving substation additionally has set of sensors of load current at substation, voltage pickup across buses of substation and logic circuit. EFFECT: simplified design, increased efficiency of frequency-current protection. 1 cl, 2 dwg
