DEVICE FOR CURRENT PROTECTION OF ELECTRICAL INSTALLATION Russian patent published in 2019 - IPC H02H3/08 

FIELD: electrical engineering.

SUBSTANCE: device for current protection of electrical plant comprises reed switch with switching, closing and opening contacts, installed in magnetic field of current conducting bus of electrical installation, first intermediate relay with contact with delay for closing, connected to circuit breaker of electric installation, constant operational current source, which negative pole is connected to the first intermediate relay control winding first end, and the positive pole is connected to the reed relay contact. Reed contact of reed switch is connected to first input of logic element AND, as well as to input of logical element NOT, output of which is connected to first input of first memory device, output of which is connected to input of first time relay and to second input of logic element AND, which output is connected to the first input of the second memory device, the output of which is connected to the input of the second time relay, to the first input of the logical OR element, as well as to the first end of the control winding of the second intermediate relay. Output of the first time relay is connected to the second input of the first memory device. Output of the second time relay is connected to the second input of the second storage device and to the first input of the third storage device, the output of which is connected to the input of the third time relay, the output of which is connected to the second input of the third storage device and to the first input of the fourth storage device, which output is connected to third input of logic element AND and to input of fourth time relay, which output is connected to second input of fourth memory device. Reed contact of reed switch is connected to first input of fifth storage device, output of which is connected to input of fifth time relay, output of which is connected to the second input of the fifth storage device, to the second input of the logical OR element, the output of which is connected to the input of the protection unit, the output of which is connected to the second end of the control winding of the first intermediate relay. Normally open contact of the second intermediate relay is connected via contact with delay to closing the first intermediate relay in the circuit of breakdown of the electric installation switch. Contact with time delay for closing of the second intermediate relay is connected through a contact for opening of the first intermediate relay to the signaling circuit, and the start button is connected to the third input of the logic element AND. To the positive pole of the source of permanent operational current, a start button, contact with time delay for closing and disconnecting contact of second intermediate relay. Second end of the control winding of the second intermediate relay is connected to the negative pole of the constant operational current source.

EFFECT: higher reliability of electric installation protection at short-circuit.

1 cl, 1 dwg