FIELD: main relay protective gear for high- and superhigh-voltage lines. SUBSTANCE: protective gear uses electromagnetic current relay with saturable current transformer whose series-connected primary windings pass line currents transformed by current transformers of phases A, B, and C. Phase B current is passed through each primary winding of saturable current transformer in opposition to circuit-by-circuit currents of phases A and C. In order to acquire data on current phase in each side of line, primary winding of intervening current transformer is connected in series with short-circuited winding circuit; secondary winding of intervening transformer is connected to data input of transceiver which converts current to high-frequency signal and conveys it to transceiver on other side of line. Upon occurrence of short circuit in line, signal picked off transceiver output and that coming from final element of electromagnetic relay provide for closing respective contacts of protective-gear breaking circuit wherefrom OFF-signal is transmitted for line disconnection. EFFECT: enhanced sensitivity and reliability, reduced mass and size of protective gear. 8 cl, 6 dwg
