CN103311921B - A kind of power supply entering line switch and bus connection switch interlock connection circuit - Google Patents

Abstract

The invention relates to an interlocking wiring circuit of a double power supply incoming line switch and a bus tie switch, comprising first and second power supply incoming line switches K1, K2 and a bus tie switch K3, the input end of the microcomputer protection unit is connected with the output end of the control switch , the output end of the microcomputer protection unit is connected to the closing circuit of any one of the three switches, and the normally closed contacts of the other two switches are connected in parallel between the control switch and the input end of the microcomputer protection unit. In this circuit, the normally closed contacts of the two switches used for locking are connected in parallel to the input end of the microcomputer protection unit. When all the parallel normally closed contacts are opened, the microcomputer protection unit can detect the disconnection of the control circuit. Avoid sending out the control loop disconnection alarm signal, and realize the blocking function at the same time.

Description

A kind of interlocking wiring circuit of dual power incoming line switch and bus tie switch

technical field

The present invention belongs to the technical field of relay protection for power systems, and in particular relates to an interlocking wiring circuit between a dual-power incoming line switch and a bus tie switch.

Background technique

For most high-voltage users, in order to ensure the reliability of power supply, the primary wiring adopts a single-bus section wiring method, and two independent power supplies are connected to each other for backup. There is a bus tie between the two bus sections, as shown in Figure 1 , when one of the power switches K1 or K2 is disconnected, the bus tie switch K3 is put into use to make both busbars electrified, but when both power switches K1 and K2 are powered, the bus tie switch K3 is turned on, which will cause different systems to be paralleled asynchronously. Harm the stability of the power system. Therefore, it is necessary to add a necessary interlock circuit to any one of the three switches—power switches K1, K2, and bus tie switch K3.

Most of the interlocking circuits are connected between the microcomputer protection device and the closing coil HQ. Figure 2 shows the interlocking circuit of the power switch K2. When the power switch K1 and the bus tie switch K3 in Figure 1 are in the closing position , the normally closed contact K1QF1 of the power switch K1 in Figure 2, the normally closed contact K3QF3 of the bus tie switch K3 are disconnected, and the closing coil HQ is not charged, then the power switch K2 in Figure 1 cannot be closed. However, when the microcomputer protection device detects the disconnection of the control loop, it always detects whether there is a disconnection between the node a of the protection device and the node b of the control power supply. Due to the normally closed contact K1QF1 of the power switch K1 and the normally closed The closing contact K3QF3 is disconnected, so that the closing circuit of the power switch K2 in the opening position is disconnected, causing the microcomputer protection device to often send a control circuit disconnection alarm signal.

Contents of the invention

The purpose of the present invention is to provide an interlocking wiring circuit between a dual-power incoming line switch and a bus tie switch that prevents the microcomputer protection device from sending a control circuit disconnection alarm signal under normal conditions.

In order to achieve the purpose of the above invention, the technical solution adopted in the present invention is: a dual power supply incoming switch and bus tie switch interlock wiring circuit, including the first and second power supply incoming switch K1, K2 and bus tie switch K3, microcomputer The input end of the protection unit is connected to the output end of the control switch, the output end of the microcomputer protection unit is connected to the closing circuit of any one of the three switches, and the normally closed contacts of the other two switches are connected in parallel to the control switch. Between the switch and the input terminal of the microcomputer protection unit.

Simultaneously, the present invention can also be further realized through the following technical measures:

Further, the microcomputer protection unit adopts a microcomputer protection chip U1, its current output pin is connected to the closing circuit of the second power supply incoming switch K2, the normally closed contact K1QF1 of the first power supply incoming switch K1, the bus tie switch The normally closed contact K3QF3 of K3 is connected in parallel, one end of the parallel connection is connected to the current input pin of the microcomputer protection chip U1, and the other end is connected to the output end of the control switch.

Preferably, the closing circuit of the second power incoming switch K2 is composed of circuit breaker auxiliary contact QF, spring energy storage contact S2, closing coil HQ, test position contact S8 and working position contact S9, the One end of the circuit breaker auxiliary contact QF is connected to the current output pin of the microcomputer protection chip U1, the other end is connected to one end of the closing coil HQ through the spring energy storage contact S2, and the other end of the closing coil HQ is connected to the test position contact. Point S8 or working position contact S9 is connected.

Further, the input end of the control switch is connected to 220V DC through the air switch DK.

Preferably, the closing circuit of the second power incoming switch K2 is connected to 220V direct current through an air switch DK.

The beneficial effect of the present invention is that the circuit connects the normally closed contacts of the two switches used for locking in parallel to the input end of the microcomputer protection unit. When all the parallel normally closed contacts are opened, the microcomputer protection unit detects When the control loop is disconnected, it can avoid sending a control loop disconnection alarm signal, and at the same time realize the blocking function.

Description of drawings

Figures 1 and 2 are schematic wiring diagrams of the prior art;

Fig. 3 is a wiring diagram of the present invention.

The meanings of the marks in the figure are as follows:

1—control switch

Detailed ways

As shown in Figure 3, a dual power supply incoming line switch and bus tie switch interlock wiring circuit, including the first and second power supply incoming line switches K1, K2 and bus tie switch K3, the input terminal of the microcomputer protection unit and the control switch 1 The output end of the microcomputer protection unit is connected to the closing circuit of any one of the three switches, and the normally closed contacts of the other two switches are connected in parallel to the input of the control switch 1 and the microcomputer protection unit. between the ends.

The microcomputer protection unit adopts a microcomputer protection chip U1, its current output pin is connected with the closing circuit of the second power supply incoming switch K2, the normally closed contact K1QF1 of the first power supply incoming switch K1, the normally closed contact of the bus tie switch K3 The closed contact K3QF3 is connected in parallel, one end of the parallel end is connected to the current input pin of the microcomputer protection chip U1, and the other end is connected to the output end of the control switch 1.

The closing circuit of the second power incoming switch K2 is composed of circuit breaker auxiliary contact QF, spring energy storage contact S2, closing coil HQ, test position contact S8 and working position contact S9. One end of the auxiliary contact QF is connected to the current output pin of the microcomputer protection chip U1, the other end is connected to one end of the closing coil HQ through the spring energy storage contact S2, and the other end of the closing coil HQ is connected to the test position contact S8 or The working position contact S9 is connected. The input end of the control switch 1 is connected to 220V direct current through the air switch DK. The closing circuit of the second power incoming switch K2 is connected to 220V direct current through the air switch DK.

Below in conjunction with Fig. 3, the working process of the present invention will be further described.

When the first power incoming switch K1 is in the closing position, its normally closed contact K1FQ1 is disconnected; when the bus tie switch K3 is in the open position, its normally closed contact K3FQ1 is closed, and the 220V DC is controlled by the air switch DK and Switch 1, the normally closed contact K3FQ3 of the bus tie switch K3, and the microcomputer protection unit supply power to the closing circuit of the second power supply incoming switch K2, and the closing circuit of the second power supply incoming switch K2 is intact and can be closed;

When the first power incoming switch K1 is in the closing position, its normally closed contact K1FQ1 is disconnected; when the bus tie switch K3 is in the closing position, its normally closed contact K3FQ3 is disconnected, and the 220V DC cannot supply the second power supply. The closing circuit of the line switch K2 supplies power, and the closing circuit of the second power incoming switch K2 is disconnected to form a lock.

Since the microcomputer protection unit detects the disconnection of the control circuit to detect whether there is a disconnection between the node a of the protection device and the node b of the control power supply, the normally closed contacts of the first power incoming switch K1 and the bus tie switch K3 are connected in parallel and then connected to The input terminal of the microcomputer protection unit prevents the disconnection detection of the control circuit from being affected by the opening and closing of the normally closed contacts of the first power inlet switch K1 and the bus tie switch K3, and avoids the microcomputer protection unit from sending a control circuit disconnection alarm signal by mistake .

The blocking loops of the three switches are the same in the present invention, and the present invention only takes the second power supply incoming switch K2 as an example. The wiring method of the blocking loop of any switch in these three switches is: the other two switches are normally closed. point in parallel, and then connected in series between its control switch 1 and the microcomputer protection unit.

In summary, the present invention connects the normally closed contacts of the two switches used for locking in parallel to the input end of the microcomputer protection unit. When all the parallel normally closed contacts are opened, the microcomputer protection unit detects the control circuit When the line is broken, it can avoid sending out the alarm signal of the control loop line break, and at the same time realize the blocking function.

Claims (3)

1. A kind of double power supply incoming line switch and bus tie switch interlock wiring circuit, comprise the first power supply incoming line switch K1, the second power supply incoming line switch K2 and bus tie switch K3, the input terminal of microcomputer protection unit and control switch ( 1) is connected to the output terminal of the microcomputer protection unit, and the output terminal of the microcomputer protection unit is connected to the closing circuit of any switch in the first power supply incoming switch K1, the second power supply incoming switch K2 and the bus tie switch K3, which is characterized in that : The normally closed contacts of the other two switches are connected in parallel and then connected between the control switch (1) and the input end of the microcomputer protection unit; The microcomputer protection unit adopts a microcomputer protection chip U1, its current output pin is connected with the closing circuit of the second power supply incoming switch K2, the normally closed contact K1QF1 of the first power supply incoming switch K1, the normally closed contact of the bus tie switch K3 The closed contact K3QF3 is connected in parallel, one end of the parallel connection is connected to the current input pin of the microcomputer protection chip U1, and the other end is connected to the output end of the control switch (1); The closing circuit of the second power incoming switch K2 is composed of circuit breaker auxiliary contact QF, spring energy storage contact S2, closing coil HQ, test position contact S8 and working position contact S9. One end of the auxiliary contact QF is connected to the current output pin of the microcomputer protection chip U1, the other end is connected to one end of the closing coil HQ through the spring energy storage contact S2, and the other end of the closing coil HQ is connected to the test position contact S8 or The working position contact S9 is connected. 2. The interlock wiring circuit of dual power incoming line switch and bus tie switch according to claim 1, characterized in that: the input end of the control switch (1) is connected to 220V direct current through the air switch DK. 3. The interlock wiring circuit of dual power supply incoming switch and bus tie switch according to claim 1, characterized in that: the closing circuit of the second power supply incoming switch K2 is connected to 220V DC through the air switch DK.