FIELD: electrical engineering. SUBSTANCE: device includes swinging interlocking 13, resistance relay unit 1 incorporating intermediate voltage and current transformers 2, 3, 4, 5, 6, 7, measurement elements 8, 9, 10 of phase resistance, first OR gate 11, AND gate 17 with three inputs which first input is connected to output of resistance relay unit 1, which second input is linked to output of swinging interlocking 13 and to first input of unit 16 of detection of operation priority which output is coupled to third of AND gate. In case of fault operation of measurement element 12 of voltage of reverse sequence is ensured. Swinging interlocking in this case does not operate. Signal from second OR gate 14 comes with time delay of element 15 to input of unit 16 of detection of operation priority. With this zero signal is established across output of the latter which goes to input of AND gate 17 and interlocks protection. EFFECT: increased reliability and efficiency of distance protection. 1 dwg
