METHOD FOR DIFFERENTIAL PROTECTION OF THYRISTOR BOOSTER DEVICE FOR REGULATION AND STABILIZATION OF VOLTAGE Russian patent published in 2019 - IPC H02H7/04 

FIELD: electrical engineering.

SUBSTANCE: according to the method current currents of each side of each phase of thyristor booster device are converted in current transformers, phase-by-phase geometrically summed currents from current transformers and when the resultant current of any phase of the specified threshold value is exceeded, power circuits are disconnected from all sides of thyristor booster device, performing a matrix description of the ratio of currents for the thyristor booster device and forming phase current matrices based on graph theory and the double recording method, graph vertices represent buses, and by arcs respectively branches of current transformers and switches, performing operations on phase current matrixes to obtain resultant currents, analyzing the ratio of resultant currents and based on the corresponding analysis checking conditions of operation of differential protection of thyristor booster device, as a criterion for checking the operability of current transformers, ratio of sums of incoming and outgoing currents is used, since each arc of the graph is reflected with the same weight corresponding to the current value in the vertex matrices twice as an arc connected to the vertex and directed to it by one vertex matrix, and as an arc connected to the vertex and directed from it by another vertex matrix, then at incorrect values produced by current transformers, the sum of incoming and outgoing currents in two matrices becomes erroneous and does not correspond to the real sum of circuit currents, faults of one or two current transformers are detected, as well as detecting damages at the thyristor booster boom bus-line device, issuing a control signal when detecting faults of current transformers, realizing the required disconnections in case of faults of the thyristor booster device jumper. Besides, current transformers are installed on all sides of the thyristor booster device elements: serial and shunt transformers, as well as thyristor commutator, in addition, vertexes of the graph represent a series and shunt transformer, as well as a thyristor switch, detecting damages of the serial and shunt transformers, as well as thyristor commutator by the ratio of currents, realizing the required disconnections in case of damages of the above elements of the thyristor booster device.

EFFECT: providing detection of faults of current transformers, issuing a control signal in case of failure of the corresponding current transformer and excluding protection action without deterioration of quick action of protection and application of additional devices.

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