RU1798848C - Gear for single-time automatic enclosure of switch - Google Patents

Abstract

The invention relates to electrical engineering. The device is controlled from the opening and closing block contact of the circuit breaker and contains a timing circuit, a voltage relay, an actuating element, a logic element I. Also an actuating element acting on the circuit breaker. In order to increase the reliability of operation, the device is equipped with a unit for generating a charging current, the time of the driving circuit, and the accuracy of the operation of the threshold element is increased by introducing a source follower between the input of the latter and the capacitor. In order to increase the safety of operation in a situation where the switch is turned off and then turned on by the operator, a capacitor discharge is provided in the device using a controlled key. 1 ill.

Description

The invention relates to electrical engineering, in particular to automatic reclosing devices (ARs) of circuit breakers in power supply systems of mines and mines, which are dangerous for the explosion of gas and dust.

The purpose of the invention is to increase the reliability of the operation of the device.

The drawing shows an electrical diagram of a device for a one-time automatic repeated switching on of a circuit breaker.

The device comprises a voltage stabilizing power supply unit 1, opening 2 and closing 16 block contacts of the switch, the first 3 and second 15 resistors that limit the amount of current flowing through the block contacts in the closed position, the charging current generating unit 4, made on An iterative amplifier 5. to the output of which a charging resistor 6 and a diode 7 are connected in series, which are covered by feedback. The output of unit 4 is connected to a common power bus via a parallel RC circuit. consisting of a capacitor 8 and a resistor 9, and through a controllable switch 10, which discharges the capacitor of the RC circuit in case of prohibition of reconnection. The voltage across the capacitor is monitored by the voltage fixing unit 11, and its comparison with the threshold is performed by the threshold element 12. The output of the voltage fixing unit 11, the output of the voltage relay 14, as well as the connection point of the resistor 15 and the closing block contact 16 connected to the inputs of the element And 13, the output of which is connected to the actuating element 17, which is made in the form of a pulse device, which is triggered by a signal of logical G, and consists of threshold inverting amplifiers 18 and 19, a capacitor 20 and included x parallel resistor 21 and diode 22,

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The device operates as follows.

If the switch is disconnected, the opening block contact 2 is closed, the capacitor 8 is not charged, a logical O signal is generated at the output of the voltage fixing unit 11, a logical O signal is generated at the output of the And 13 element, and the device does not work. .. „... /: .- ...

When the circuit breaker is turned on quickly, the contact block 2 opens and the output voltage of the power supply unit 1 is set at the input of the charging current generating unit 4, after which the capacitor 8 is charged with the output current of the charging current generating unit 4. The time interval when charging the capacitor determines the time the device is ready and excludes the possibility of repeated switching on when the circuit breaker is tripped by protection in the event of a short circuit on the substation buses. The capacitor charge time is determined by its capacity and the resistance value of the charging resistor 6. The voltage on the capacitor is controlled by the voltage fixing unit 11, and when it reaches a value exceeding the threshold value, the output signal of the unit changes its value from logical O to logical 1 , In this case, the device does not work, since the contact block 16 is closed and the element 13 is blocked.

In the event of a voltage failure, the circuit breaker is tripped using an undervoltage relay (not shown), pin 2 closes, pin 16 opens, and capacitor 8 discharges to resistor 9. Discharging the capacitor to the threshold voltage value is provided in a time which determined by the conditions for the safe operation of underground electrical networks and becomes for networks with a voltage of 6 kV - 180 s, and for networks with a voltage below 1 kV - 60 s. If the interruption in the power supply lasted more than the time specified by the safety conditions, then the voltage supplied to the input of the threshold element 12 becomes lower than the threshold value, a logical O signal is generated at the output of the latching unit 11, which blocks the And 13 element and does not restart the circuit breaker . If the mains voltage appears earlier than the time specified by the safety condition, the output signals of the latching unit 11, the voltage relay14, as well as the signal generated by the closing block contact 16, take the value of logical Г and the output of element And 13 is set to logic 1. Actuator 17 trips and the switch turns on. After the switch is turned on, the block contact 16 closes and removes the operation signal from the input of the actuator.

The voltage fixing unit 11, made in the form of a source voltage follower, the output of which is connected to a threshold element, allows to increase

accuracy of fixing the time interval, which corresponds to the duration of the break in the power supply.

With a long supply of a response signal to the input of the actuating element,

for example, in the event of a failure of the block contact 16 of the switch, the actuating element 17 generates a signal of action of the AP B is limited,

duration, which excludes multiple automatic starts. Besides

This reduces the overall dimensions and weight of the AP device B.

The use of the proposed device in mine explosion-proof electrical apparatus allows to increase the reliability of the automatic restart operation by increasing the accuracy of fixing the duration of the interruption in the power supply and preventing repeated power-ups

circuit breaker, eliminating the possibility of an explosion of methane-air mixture in underground workings. Formula A from Breteni

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Claims (2)

1. A device for a single automatic repeated switching on of a circuit breaker comprising a stabilized power supply unit, opening and closing block contacts of the switch, a charging resistor and a diode, a voltage relay, an RC circuit and an actuating element, characterized in that, in order to increase the reliability of operation, a block is inserted into it the formation of the charging current, the block voltage clamp, three-input element And, the first and second limiting resistors and a controlled key, while the input of the block forming the current through the first limiting resistor is connected to the output of the power supply unit, and through the opening block contact, to the common bus of the power supply unit, the output of the forming unit through a parallel RC circuit and a controlled key connected to the common power bus, the first input of the And element, the output of which is connected to the input of the actuator, is connected through the second resistor to the output of the power supply and through the make contact with the common bus, the second input is connected to the output of the voltage relay, the inputs of which are connected to the output of the power supply unit and the common bus, the third input through the voltage fixing unit is connected to the output of the forming unit. 2. The device according to claim 1, wherein the voltage fixing unit comprises a source voltage follower and a threshold element respectively connected in series.