FIELD: electrical engineering. SUBSTANCE: relay has series-connected intermediate three-phase potential transformer 1, three-phase rectifier 2, threshold element 3, pulse counter 4, storage register 5, and decoder 6 whose output functions as relay output, null-indicator 7 connected through its inputs to outputs of transformer 1, first decoder 8 inserted between one of outputs of null-indicator and recording input of storage register, delay unit whose input is connected to output of null-indicator 7 and output, to reset input of pulse counter 4 through second decoder 10; in addition, it is provided with time gate 11 and output element 12 connected in series, logical position follower of generator circuit breaker 13, and AND gate 14; relay decoder 6 is connected to control input of time gate 11 and to one of inputs of AND gate 14 whose other input is connected through logic follower 13 to output of element 12; output of AND gate 14 is connected to data input of time gate 11 and functions as blocking input of warning unit. Introduction of logic follower 13 and AND gate 14 makes it possible to distinguish relay operation in response to connection to generator buses before desired voltage is built up from other emergency conditions and to use output signal of AND gate for blocking synchronizing unit. EFFECT: improved reliability of protective gear. 7 dwg
