CN204314645U - A kind of low-voltage distribution system by screen break-make automaton - Google Patents

Abstract

A screen-by-screen on-off automatic control device for a low-voltage power distribution system, including several power distribution panels, the power supply circuit of the power distribution panel is connected with an on-off control main circuit, and the on-off control main circuit includes a relay parallel circuit, a universal circuit breaker, and a universal circuit breaker. One end of the first auxiliary normally closed contact of the device is connected to the power circuit of the power distribution panel, and the other end is connected to the parallel circuit of the relay. The relay parallel circuit includes AC, time and intermediate relays. The normally closed contact of the AC relay is connected in series with the coil of the time relay, and the normally open contact of the time relay and the coil of the intermediate relay are connected in series. The normally open contact of the intermediate relay and The series circuit of the coil of the AC relay is connected in parallel, the normally closed contact of the time relay of the first power distribution panel is connected in the power supply circuit of the second power distribution panel, and the other power distribution panels are analogized in turn. By connecting the on-off control main circuit on each power distribution panel, the on-off of each power distribution panel can be realized one by one, and the excessive current in the line caused by simultaneous on-off can be prevented.

Description

A screen-by-screen on-off automatic control device for low-voltage power distribution system

technical field

The utility model belongs to the field of low-voltage power distribution control, in particular to a screen-by-screen on-off automatic control device for a low-voltage power distribution system.

Background technique

In the existing low-voltage power distribution system, the components that can control the on-off of the circuit usually include a circuit breaker with an arc extinguishing device, a knife switch, a fuse, and the like. Because the low-voltage system carries many loads and the current passing through the circuit is large, in order to ensure the safety of the components that control the on-off of the circuit, only a circuit breaker with an arc extinguishing device can be used to control the on-off of the circuit. However, in real life, the low-voltage power distribution system in the power distribution room is a multi-channel output controlled by multiple power distribution panels at the same time, which is generally manually controlled on and off screen by screen according to the power distribution panels. There are also some automatic control devices used for low-voltage on-off, which are only suitable for devices with only one control panel. At the same time, there are no matching protection devices to automatically deal with problems such as under-voltage, over-current, and overload, which may easily lead to fire accidents. occur, which is not conducive to the safe use of electricity. If the on-off of the multi-screen power distribution system is manually controlled at the same time, the load of the entire low-voltage system will increase, and low voltage and high current will be generated instantaneously, which will cause the temperature of the low-voltage side winding of the transformer to rise due to the increase in current, resulting in Phase-to-phase insulation is aging, which reduces the service life of the equipment; at the same time, a strong flame discharge will be generated at the on-off switch, which is more likely to cause a fire accident.

However, so far, there has not been a more scientific and reliable low-voltage control device that can automatically control multiple screens and is on and off screen by screen.

Utility model content

The utility model aims to provide a screen-by-screen on-off automatic control device for a low-voltage power distribution system which is convenient to use.

In order to solve the above technical problems, the utility model provides the following technical solutions: a screen-by-screen on-off automatic control device for low-voltage power distribution systems, including several power distribution screens, and the power supply circuit of each power distribution screen is connected The on-off control main circuit, the on-off control main circuit includes a relay parallel circuit and a universal circuit breaker, one end of the first auxiliary normally closed contact of the universal circuit breaker is connected to the power circuit of the power distribution panel, and the other end is connected to the relay Parallel circuit, relay parallel circuit includes AC relay, time relay and intermediate relay, the normally closed contact of the AC relay is connected in series with the coil of the time relay, and the series circuit of the normally open contact of the time relay and the coil of the intermediate relay and the intermediate relay The series circuit of the normally open contact and the coil of the AC relay is connected in parallel, and the normally closed contact of the time relay of the first power distribution panel is also connected in the power supply circuit of the second power distribution panel, and the second power distribution panel The normally closed contact of the time relay is also connected in the power supply circuit of the third power distribution panel, and other power distribution panels are analogized in turn.

A normally open contact of a relay is connected in series between the universal relay and the parallel circuit of the relay, and the coil of the relay is connected with the auxiliary control circuit.

The auxiliary control circuit includes an AC-to-DC circuit, a triode and a NE555 time base circuit, the AC-to-DC circuit includes a step-down current-limiting circuit, a bridge rectifier circuit and a filter capacitor, and one end of the step-down current-limiting circuit is connected to the AC input terminal, the other end is connected to the bridge rectifier circuit, the positive output terminal of the bridge rectifier circuit is connected with a filter capacitor, and the positive output terminal of the bridge rectifier circuit is connected to the base and collector of the triode through the second resistor and the third resistor respectively , the base of the triode is also connected to the negative output terminal of the bridge rectifier circuit through the fourth resistor, the emitter of the triode is connected to the emitter of the bridge rectifier circuit through the fifth resistor, and the collector of the triode is connected to the input terminal of the NE555 time base circuit, The power supply end of the NE555 time base circuit is connected to the positive output end of the bridge rectifier circuit, the common end of the NE555 time base circuit is connected to the negative output end of the bridge rectification circuit, and the output end of the NE555 time base circuit is connected to the coil of the relay.

An alarm circuit is also connected to the power distribution panel circuit, and the alarm circuit includes an alarm, an electronic composite switch and a universal circuit breaker, one end of the second auxiliary normally closed contact of the universal circuit breaker is connected to the power distribution panel circuit, and the other One end is connected with an electronic composite switch, and the electronic composite switch is electrically connected with an alarm.

The load circuit of the power distribution screen is also connected with a protection circuit, the protection circuit is connected to the power distribution screen circuit through the main normally open contact of the universal relay, and the protection circuit includes a microcomputer integrated protector, and a microcomputer integrated protector The signal input end is connected to the signal output end of the voltage signal acquisition circuit and the current signal acquisition circuit, the two soft relay signal output ends of the microcomputer integrated protector are connected in series in the power circuit of the universal circuit breaker, and the signal output end of the microcomputer integrated protector is The tripping coil of the universal circuit breaker and the closing coil of the universal circuit breaker connected in series with the normally open contacts of the AC relay are respectively connected.

The voltage signal acquisition circuit includes a voltage transformer, and the current signal acquisition circuit includes a protection current transformer, a measurement current transformer and a zero-sequence current transformer.

Through the above technical scheme, the beneficial effects of the utility model are as follows: 1. By connecting the on-off control main circuit in the power supply circuit of each power distribution panel, the automatic on-off of each power distribution panel in sequence is realized to prevent simultaneous on-off from causing 2. By connecting the normally closed contact of the universal circuit breaker in the power circuit of the power distribution panel, it can prevent the back and forth of the power distribution panel; 3. The setting of the alarm circuit When the on-off control main circuit loses power, it can send an alarm signal to notify the maintenance personnel to repair in time; 4. The setting of the protection circuit can protect the safe operation of the load of the power distribution panel, and cut off the circuit of the corresponding load when an abnormal situation occurs .

Description of drawings

Fig. 1 is the schematic diagram of the utility model on-off control main circuit;

Fig. 2 is a schematic diagram of the auxiliary control circuit of the utility model;

Figure 3 is a block diagram of the protection circuit.

Detailed ways

As shown in Figure 1, Figure 2 and Figure 3, a screen-by-screen on-off automatic control device for a low-voltage power distribution system, taking the first power distribution screen as an example. Connect the on-off control main circuit to the power supply circuit of the first power distribution panel. The on-off control main circuit includes a relay parallel circuit, a relay and a universal circuit breaker DQ. One end of the first auxiliary normally closed contact of the universal circuit breaker DQ is connected to the power distribution panel. The power circuit of the screen, the other end is connected to one end of the normally open contact K1 of the relay K1, and the other end of the normally open contact of the relay K1 is connected to the relay parallel circuit. The relay parallel circuit includes AC relay KM, time relay KT, intermediate relay KA, the normally closed contact of AC relay KM is connected in series with the coil of time relay KT to form the first series circuit, the normally open contact of time relay KT is connected with the intermediate relay KA The coils of the intermediate relay KA are connected in series to form a second series circuit, the normally closed contact of the intermediate relay KA is connected in series with the coil of the AC relay KM to form a third series circuit, the normally open contacts of the AC relay KM and the coil of the universal circuit breaker DQ are connected in series to form a The fourth series circuit, the first, second, third, and fourth series circuits are connected in parallel. On the one hand, a chain reaction is generated during control to make each contact act accordingly. On the other hand, the stability of the circuit is ensured to prevent continuous communication. broken problem.

In order to control the on-off of the normally open contact of the relay K1, the coil of the relay K1 is connected to the auxiliary control circuit, so as to control the on-off of the contact of the relay K1, and realize the automatic on or off of the power circuit of the power distribution panel. The auxiliary control circuit includes an AC to DC circuit, a transistor Q, and a 555 time base circuit U1. The AC to DC circuit includes a step-down current-limiting circuit composed of the first resistor R1 and the first capacitor C1 connected in parallel, and a bridge circuit composed of the first, second, third, and fourth diodes D1, D2, D3, and D4. A rectifier circuit and a second capacitor C2 for filtering. One end of the parallel circuit of the first resistor R1 and the first capacitor C1 is connected to the interface J1, and the other end is connected to the anode of the first diode D1 and the cathode of the second diode D2 of the bridge rectifier circuit, and the third diode D3. The anode and the cathode of the fourth diode D4 are connected to the interface J2, the interface J1 and the interface J2 are connected to the mains, the anode of the second diode D2 and the anode of the fourth diode D4 are grounded, and the cathode of the first diode D1 The negative pole of the third diode D3 is connected to the first terminal of the second capacitor C2, and the second terminal of the second capacitor C2 is connected to the positive pole of the second diode D2 and the positive pole of the fourth diode D4, so that in step-down After the current is limited, the AC power is converted into DC power through the bridge sorting circuit, and then the rectified DC power is filtered out clutter through the second capacitor C2. The first end of the second capacitor C2 is also connected to the first end of the second resistor R2 and the first end of the third resistor R3 connected in parallel, the second end of the second resistor R2 is connected to the first end of the fourth resistor R4, The second end of the third resistor R3 is connected to the first end of the fifth resistor R5, and the second ends of the fourth resistor R4 and the fifth resistor R5 are both grounded. The second end of the second resistor R2 is also connected to the base of the triode Q, the collector of the triode Q is connected to the second end of the third resistor R3, and the emitter of the triode Q is connected to the first end of the fifth resistor R5. Transistor Q on and off control. The collector of the transistor Q is also connected to the input terminal of the 555 time base circuit U1 (port 2), the output terminal of the 555 time base circuit U1 (port 3) is connected to one end of the coil of the relay K1, and the other end of the coil of the relay K1 is grounded . The power input terminal (ports 4 and 8) of the 555 time base circuit U1 is connected to the first terminal of the second capacitor C2, and the first common terminal (port 5) of the 555 time base circuit U1 is grounded through the third capacitor C3. The second common terminal (port 1) of the base circuit U1 is directly grounded. The auxiliary control circuit can control whether the coil of the relay K1 is energized, thereby controlling the closing or connecting of the normally open contact of the relay K1.

The power circuit of the power distribution panel is also connected with an alarm circuit. The alarm circuit includes an alarm HA and an electronic composite switch U2. One end of the second normally closed contact of the universal circuit breaker DQ is connected to the power circuit of the power distribution panel, and the other end is connected to the electronic composite switch Switch U2, the electronic compound switch U2 is connected to the alarm HA. When the on-off control main circuit is not energized, the second normally closed contact of the universal circuit breaker DQ is disconnected, so that the alarm HA sends out an alarm signal to notify the maintenance personnel to perform maintenance in time.

In order to ensure the safe operation of the circuit, the normally open contact of the universal circuit breaker DQ is connected in series in the load circuit of the power distribution panel, and the load circuit of the power distribution panel is also connected with a protection circuit. The protection circuit includes a microcomputer integrated processor, a microcomputer integrated The signal input terminal of the processor is connected to the voltage transformer, protection current transformer, measurement current transformer and zero-sequence current transformer. In the power circuit of the circuit breaker DQ, the integrated processor of the microcomputer is also connected with the series circuit of the normally open contact of the AC relay KM, the first closing coil HQ2 of the universal circuit breaker DQ, and the tripping coil TQ of the universal circuit breaker DQ. The microcomputer integrated processor analyzes and compares the signals measured by the voltage transformer, protection current transformer, measuring current transformer and zero-sequence current transformer to see if the load line is running normally; when it is not normal, the output signal makes the universal circuit breaker The trip coil TQ of DQ is energized, and the first and second normally closed contacts of the universal circuit breaker DQ in the power circuit of the power distribution panel are disconnected, thereby closing the power circuit of the power distribution panel to prevent dangerous accidents.

The above is the connection method of the first power distribution panel, the connection method of the remaining power distribution panel is the same as that of the first power distribution panel, the only difference is: the connection of the second power distribution panel: connect the first On-off control on the power distribution panel The normally closed contact of the time relay KT in the main circuit is connected in series with the power supply circuit of the second power distribution panel; The normally closed contacts of the time relay KT in the control main circuit are connected in series in the power supply circuit of the third power distribution panel, and the other power distribution panels are analogized in turn.

During the working process, when the power circuit of the first power distribution panel is connected, the coil of relay K1 is energized, the main circuit of on-off control is connected, the coil of time relay KT is energized, and the normally open contact of time relay KT is extended. When the coil is closed; the coil of the intermediate relay KA is energized, the normally closed contact of the intermediate relay KA is disconnected, the coil of the AC relay KM is de-energized, and the normally closed contact of the AC relay KM is disconnected, and finally the coil of the AC relay KM is energized. Power, the first closing coil switch HQ1 of the universal circuit breaker DQ is energized, and the first auxiliary normally closed contact of the universal circuit breaker DQ is disconnected, thereby preventing back and forth on-off. After the power circuit of the first power distribution panel is connected, the normally closed contact of the time relay KT of the first power distribution panel is disconnected after a delay, thereby connecting the power circuit of the second power distribution panel. The on-off methods of the following power distribution panels are analogized in turn, so as to realize the gradual on-off of each power distribution panel, and prevent the simultaneous on-off of each power distribution panel, resulting in excessive current changes in the line and dangerous accidents.

When the operation of the power distribution panel is abnormal, the integrated microcomputer processor will output a signal to make the trip coil TQ of the universal circuit breaker DQ power off, so that the main normally open contact of the universal circuit breaker DQ is disconnected, thereby protecting the corresponding power distribution Screen load circuit.

The circuit principle of the utility model is simple. By connecting the on-off control main circuit on each power distribution panel, the on-off of each power distribution panel can be realized one by one, so as to prevent the excessive current in the line caused by simultaneous on-off and fire accidents. The protection circuit is connected to the load circuit of the power distribution panel, so that when the load of the power distribution panel is abnormal, the line is cut off in time to prevent accidents.

Claims (6)

1. a low-voltage distribution system is by screen break-make automaton, comprise several switchboards, it is characterized in that: all connect break-make in the power circuit of described each switchboard and control main circuit, break-make controls main circuit and comprises relay parallel circuit and universal circuit breaker, first auxiliary normally closed contact one end of universal circuit breaker connects the power circuit of switchboard, the other end connects relay parallel circuit, relay parallel circuit comprises AC relay, the time relay and auxiliary reclay, the normally closed contact of AC relay and the coils connected in series of the time relay connect into the first series circuit, the normally opened contact of the time relay and the coils connected in series of auxiliary reclay connect into the second series circuit, the normally opened contact of auxiliary reclay and the coils connected in series of AC relay connect into the 3rd series circuit, the normally opened contact of AC relay and the closing coil of universal circuit breaker are serially connected in the 4th series circuit, first, second, 3rd, 4th series circuit is connected in parallel, the normally closed contact of the time relay of the first switchboard is also connected in the power circuit of the second switchboard, and the normally closed contact of the time relay of the second switchboard is also connected in the power circuit of the 3rd switchboard, other each switchboard the like.

2. low-voltage distribution system as claimed in claim 1 is by screen break-make automaton, and it is characterized in that: the normally opened contact being in series with relay between described Universal relay and relay parallel circuit, the coil of relay is connected with auxiliary control circuit.

3. low-voltage distribution system as claimed in claim 2 is by screen break-make automaton, it is characterized in that: auxiliary control circuit comprises AC-DC circuit, triode and 555 time base circuits, AC-DC circuit comprises step-down current-limiting circuit, the bridge rectifier circuit be made up of first, second, third, fourth diode and the second electric capacity that the first resistance and the first Capacitance parallel connection connect to form, parallel circuit one end of first resistance and the first electric capacity connects the positive output end of civil power, the other end connects the positive pole of the first diode and the negative pole of the second diode, the positive pole of the 3rd diode and the negative pole of the 4th diode connect the negative output terminal of civil power, the positive pole of the second diode and the plus earth of the 4th diode, the negative pole of the first diode is connected the first end of the second electric capacity with the negative pole of the 3rd diode, second end ground connection of the second electric capacity, the first end of the second electric capacity is also connected with the first end of the second resistance be connected in parallel and the first end of the 3rd resistance, second end of the second resistance connects the first end of the 4th resistance, second end of the 3rd resistance connects the first end of the 5th resistance, the equal ground connection of second end of the 4th resistance and the 5th resistance, the base stage of the second end of the second resistance also connecting triode, the collector of triode connects the second end of the 3rd resistance, the emitter of triode connects the first end of the 5th resistance, the collector of triode also connects the input end of 555 time base circuits, the output terminal of 555 time base circuits connects one end of the coil of relay, the other end ground connection of the coil of relay, the power input of 555 time base circuits connects the first end of the second electric capacity, the common end grounding of 555 time base circuits.

4. low-voltage distribution system as claimed in claim 3 is by screen break-make automaton, it is characterized in that: in the power circuit of described switchboard, be also connected with warning circuit, warning circuit comprises alarm, electron recombination switch and universal circuit breaker, second auxiliary normally closed contact one end of universal circuit breaker connects the power circuit of switchboard, the other end connects electron recombination switch, electron recombination switch electrical connection alarm.

5. low-voltage distribution system as claimed in claim 4 is by screen break-make automaton, it is characterized in that: in the load circuit of described switchboard, be also connected with protection circuit, protection circuit is connected with load circuit by the main normally opened contact of Universal relay, described protection circuit comprises computer integrated protection devices, the signal input part of computer integrated protection devices is connected with the signal output part of voltage signal acquisition circuit and current signal Acquisition Circuit, 2 soft relay signal output parts of computer integrated protection devices are series in the power circuit of universal circuit breaker, the breaking coil signal output part of computer integrated protection devices being connected to universal circuit breaker and the closing coil of universal circuit breaker be connected in series with the normally opened contact of AC relay.

6. low-voltage distribution system as claimed in claim 5 is by screen break-make automaton; it is characterized in that: described voltage signal acquisition circuit comprises voltage transformer (VT), and current signal Acquisition Circuit comprises protective current mutual inductor, measurement current transform er and zero sequence current mutual inductor.