DEVICE FOR PROTECTION OF THREE PARALLEL LINES Russian patent published in 2014 - IPC H02H3/32 H02H7/26 

FIELD: electricity.

SUBSTANCE: invention refers to electric engineering, and namely to relay protection, and it can be used for short-circuit protection of three parallel lines. For this purpose the declared device contains one maxi-selector for the same phases of each line, one comparator for each phase, current relay and transductor, logic unit common for all lines; at that current relays and transductors are connected to primary windings of respective current transformers while inputs of maxi-selectors and first inputs of comparators are connected to secondary windings of respective transductors of the same phases and outputs of maxi-selectors are connected to the second inputs of comparators, outputs of comparators and current relays are connected to inputs of logic unit and outputs of the latter are connected to trip circuit of circuit breakers of the first, second and third line.

EFFECT: increasing operating selectivity of the device.

6 dwg