NEGATIVE SEQUENCE CURRENT FILTER ON REED SWITCHES Russian patent published in 2023 - IPC H02H3/38 

FIELD: electric power industry.

SUBSTANCE: inventiob relates to the field of electric power industry to protect electrical installations from phase-to-phase short circuits. The negative sequence current filter contains the first and second reed switches, the actuator, the first and second windings wound on the first and second reed switches, respectively, the first amplifier, the first phase-shift circuit. According to the invention, the third and fourth reed switches are introduced into the filter. The contacts of the first and fourth reed switches are connected to the input of the OR element, the output of which is connected to the direct input of the AND element with one inverse input, the logical part is connected to the output of the AND element with one inverse input, and the output to the executive body. The third and fourth windings are wound on the third and fourth reed switches, respectively, and the second amplifier is connected to the third winding, the second phase-shift circuit is connected by inputs to the outputs of the second amplifier, and by outputs, through the second control resistor, to the fourth winding. The comparison unit is connected by inputs to the outputs of the first and fourth windings, and by the output to the signaling unit and the inverse input of the AND element with one inverse input.

EFFECT: expanding the functionality of the negative sequence current filter on reed switches by detecting faults in the control windings.

1 cl, 1 dwg