RU1802894C - Device for automatic reclosing of converter - Google Patents

Abstract

SUMMARY OF THE INVENTION: in the event of a brief interruption in the supply network, the device forcibly disconnects the machine converter and allows it to be switched on again only after the end of transient processes in the switching circuits of the converter. This is achieved by organizing a circuit of elements forming a pulse, which prevents an unacceptably fast reconnection of the converter, which eliminates the emergency mode in the short-circuit network in the converter. 3 ill.

Description

The invention relates to electrical engineering, and in particular to emergency control devices in remotely controlled radio engineering installations incorporating electromechanical converters of an industrial network to an increased frequency network, during short-term failure and restoration of the supply network at the input of the converter.

The aim of the invention is to increase the reliability of the switched-on electric machine converter by eliminating emergency conditions during automatic restart after a short-term power failure, by forcibly disconnecting the converter and allowing it to turn on again after the end of transient processes in the switching circuits of the converter.

In FIG. 1 shows a functional diagram of an automatic reclosure device, excluding

occurrence of the short circuit mode in the network; in FIG. 2 - a known reclosure device; in FIG. 3 - functional diagram of the pulse shaper. - The automatic reclosure device (Fig. 1) contains a rectifier 1, the input of which is connected to the network, and the output through the isolation diode 2 and capacitive storage 3 is connected to the input of the stabilizer 4, the output of which through the divider 5 is connected to the inverse the input of the comparator 6, to the non-inverting input of which the rectifier 1 output is connected via the second divider 7; a differentiating circuit 8, a pulse shaper 9, the input of which through a differentiating circuit 8 is connected to the output of the comparator 6, and the output to the relay 10, switching contact

11 which is included in the Start button chain

12 and Stop 13 turning the converter on and off and into the 27 V circuit of the same converter, i.e. to the coils for turning on and off the starter 14. Adjustable de00

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the diverter 5 contains two resistors 15 and 16 and a capacitor 17. The divider 7 contains two resistors 18 and 19 and a capacitor 20. The AR device in FIG. 2 contains, in addition to the above elements 11-14 and the contact block 21 of the starter (shown in Fig. 1), also a group of 22 reclosure elements according to ed. testimonial. No. 1504708: switch 23, shunt thyristor 24, auxiliary thyristor 25, time setting capacitor 26, transistor 27, diode 28 ,. Zener diode 29, diodes 30-35 and resistors 36-41.

The rectifier 1 is made on a transformer and a diode bridge, the voltage stabilizer 4 for 15V is made on the 142EN8V microcircuit in accordance with BKO.347.098 TU7. The comparator used on the chip 521 SAZ in accordance with BKO.347.015 TU. The differentiating circuit 8 is made on two resistors and a capacitor and serves to produce a trigger pulse of negative polarity, which includes a pulse shaper 9. Pulse shaper 9 of FIG. 3 is made on a chip M1006VI1 in accordance with the engineering rules and methods set forth in B KO.347.395-001 TU. R and C are connected to the chip, providing a delay for the duration of the transient in the switching circuits of the converter.

Under normal conditions, the operation of the device is as follows. If there is a 50 Hz network, the starter 14 is turned on by the button 12 Start up. In this case, the rectifier 1 supplies the voltage to the divider 7, which has a small time constant, and to the capacitive storage 3 through a decoupling diode 2, which maintains the voltage at the input of the stabilizer 4 during the transition process in the switching circuits of the converter (for example, 1 -2 sec.). An adjustable divider 5 is connected to the output of the stabilizer 4, the output of which is connected to the inverting input of the comparator 6. The voltage from the divider 7 is applied to the non-inverting input of the comparator 7. The output of the comparator b is connected through the differentiating circuit 8 to the input of the pulse former 9, and the output of the pulse former 9 is connected with relay 10.

With a decrease in the voltage at the non-inverting input of the comparator b, which accompanies the short-term loss of the mains supply, the voltage at the inverting input of the comparator due to the capacitive storage 3 and the stabilizer 4 is maintained constant for a period of time sufficient to end the transient processes in the converter (up to 1 second). .

When the voltage at the non-inverting input compares or becomes lower than the voltage of the inverting input, the comparator 6 switches and through the differentiating

circuit 8 will start the pulse shaper 9 with a negative pulse, which for a specified time (1-2 seconds) will turn on the relay 10, which will break the chain of the start-up command of the starter 14 and at the same time give a command to disconnect it via the + 27V circuit, block contact 21 and contact 11 relay 10.

When restoring the mains supply, a group of 22 elements of the known automatic reclosure ensures automatic restarting of the starter (without the use of the invention for a period of about 20 ms) by turning on the thyristor 24 in a circuit: resistor 39, diode 30, on contact of the switch 23, bypass closing contact 12 in the starter coil 14. The circuit breaker 23 must first be turned on. The ability to turn on the thyristor 24 is provided by the discharge

normally charged through the circuit: on contact 23, resistor 37 and diode 28 of capacitor 26 through the control circuit (resistors 38.41, base-emitter junction) of transistor 27. Upon termination

0 bit of the capacitor 26, the transistor closes, which leads to the inclusion of the thyristor 25 in the circuit: the resistor 40 and the diode 35 and the ban on the thyristor 24. The charge voltage of the capacitor 26 is determined

5 zener diode 29, Diodes 31, 32 stabilize the voltage of the base-emitter junction of the transistor27. Diodes 34.35 compensate for the saturation voltage of transistor 27. Resistor 36 discharges capacitor 26 at

0 switch off the starter with the button 13 Stop. However, the group of 22 elements of the automatic re-enable device according to ed. testimonial. No. 1504708 provides automatic restart of the starter

5 only after the time interval specified by the pulse shaper 9, i.e. after the relay 10 has returned to its initial state and the end of the transient process in the power control circuits of the previously switched off converter, this eliminates the short circuit mode.

The use of the proposed device while maintaining all the advantages of the known automatic reclosure device with a relatively small increase in cost and labor due to the addition of several microcircuits will eliminate the emergency mode in the network due to a short circuit in the power switching elements of the converter. This device will increase the reliability of the radar system for air traffic control, because previously, if there was only a reclosure, the network supplying the complex went down, down to the substation.

Claims (1)

SUMMARY OF THE INVENTION A device for automatically reconnecting a converter, comprising a converter on and off circuit, consisting of a series-connected NC contact Stop, an NC contact, a magnetic starter coil connected between the positive and negative power supply bus, parallel to the NC contact, an NC block contact is connected magnetic starter, the first thyristor connected in series with the first resistor, the first diode and capacitor parallel to the latter, the second resistor and the make contact Stop are connected in series, the anode of the first thyristor is connected to its control electrode through the third resistor and the second diode and to the control electrode of the second thyristor through the fourth resistor and third diode, the anodes of the second diode and second thyristor are combined , the anode of the third diode is connected to the collector of the transistor, between the cathode of the second thyristor and the emitter of the transistor, the fourth and fifth diodes are connected in series, also to the emitter under oedinen anode of the zener diode and the first terminal of the capacitor, and through the first normally open contact switch coupled to the emitter terminal of the coil of the magnetic actuator, before designated for connection to the negative terminal of the power supply, the cathode of the first thyristor is connected to the pin the contact block of the magnetic starter, the contact of the Start button and the coil of the magnetic starter through the second make contact of the switch, the second terminal of the capacitor is connected to the cathodes of the first diode and the zener diode and through the fifth and sixth resistors connected in series with the base of the transistor, the common point of the fifth and sixth resistors is connected through the sixth and seventh connected in series diodes with the first output of the capacitor, characterized in that, in order to increase the reliability of the switched converter, a rectifier, an isolation diode, and capacitive are introduced into it the drive, stabilizer, the first and second divider, the comparator, the pulse shaper and the differentiating circuit, the input of the rectifier is connected to the network, and the output through the isolation diode, capacitive storage, the stabilizer and through the first divider is connected to the inverting input of the comparator, to the non-inverting input of which the output is connected the second divider, the input voltage of which is supplied from the output rectifier, pulse shaper, the input of which through the differentiating circuit is connected to the output of the comparator, and the output to the relay winding, relay contacts are the Stop and Start contacts of the converter on and off circuit.