METHOD OF DIFFERENTIAL PROTECTION OF ELECTRICAL NETWORK PARTS Russian patent published in 2018 - IPC H02H3/26 

FIELD: electrical engineering.

SUBSTANCE: according to a method for protecting a portion of an electrical network comprising at least one pair of bus systems interconnected in each pair via a three-phase bus coupler, in the current transformers, the currents of each phase of each connection connected to the corresponding bus through its switch are converted, as well as the currents of each phase of the bus coupler on the side of each of the bus systems, form a three-phase sequence of currents by geometrically summing the currents obtained by transforming the currents of the respective phases of all connections, as well as flowing through the bus coupler, if the resultant currents of the threshold levels deviate, a signal is sent to turn off the damaged element. At the same time, the cable section of the cable-overhead transmission lines is included in the electrical network section, current transformers transform the currents of each phase at the ends of the cable sections of the cable and overhead power lines, the three-phase sequence of currents includes the currents of each phase at the ends of the cable sections of the cable-overhead power lines, in addition to obtaining the resultant currents, which provide verification of the conditions for the tripping of the differential protection of the electric network section, combinations of sums and differences of the current sequences are formed using the double recording method, identify faults of current transformers of bus connections, cable sections of cable and overhead power lines and bus coupler according to the ratio of resulting currents. With the detected faults of the respective current transformers, a signal is output to output current transformers for repair and to eliminate unnecessary differential protection operations.

EFFECT: increase the reliability of the differential protection method.

1 cl, 4 dwg, 1 tbl