Switching control method of an electrical device control circuit

Abstract

The application discloses a kind of tripping and closing control method of electrical equipment control circuit, S1, the coil of latching relay is powered, the normally open contact of latching relay is closed;S2, when closing control switch is closed, the closing control voltage of microcomputer protection module output is passed through the normally closed contact of cut-off relay by continuous closing signal, so that the closing coil of circuit breaker is powered;S3, the first normally open auxiliary contact of circuit breaker is closed, the loop where the trip coil of circuit breaker is in closed state, at this time, microcomputer protection module does not output control voltage for tripping, and the trip coil of circuit breaker is in power-off state;S4, when the trip voltage signal of trip output end of microcomputer protection module is output, the trip coil of circuit breaker is powered, the main switch of circuit breaker is in open state, and circuit breaker completes tripping.The application not only can avoid circuit to continuously give circuit breaker closing signal after closing, but also can automatically trip.

Description

Technical Field

[0001] This invention relates to the field of electrical equipment protection, and more specifically to a tripping and closing control method for electrical equipment control circuits. Background Technology

[0002] Currently, in commonly used overcurrent protection systems, the conventional method for load current detection is to use a current transformer to sample the load current, convert it into a voltage value, rectify it, and then send it to the A / D port of the control chip. The A / D value is used to determine whether the load is overcurrent, thus protecting the load. However, this circuit structure is relatively heavy, and it requires the support of the control chip's A / D port. Therefore, in situations where space is limited, A / D port resources are scarce, and additional software control modules are lacking, existing technology cannot effectively perform overcurrent protection.

[0003] Currently used overcurrent and overvoltage protection devices include a voltage detection module, a current-to-voltage conversion module, and a voltage threshold discrimination and processing module, a bistable latch module, and a relay drive module, all connected to the power supply circuit module. One end of the voltage detection module is connected to the power grid, and the other end is connected to the voltage threshold discrimination and processing module. The current-to-voltage conversion module is connected to the voltage threshold discrimination and processing module, and the bistable latch module is connected to both the voltage threshold discrimination and processing module and the relay drive module. The power supply circuit module is connected to a digital radio frequency (RF) circuit module, which in turn is connected to the bistable latch module. This technical solution, like existing solutions, still requires analog-to-digital conversion and A / D port resources. In situations with high space requirements, limited A / D port resources, and a lack of additional software control modules, existing technologies cannot perform overcurrent protection. Summary of the Invention

[0004] This invention provides a tripping and closing control method for electrical equipment control circuits. This invention can not only avoid the circuit continuously sending a closing signal to the circuit breaker after closing, but also automatically trip the circuit breaker.

[0005] The tripping and closing control method for electrical equipment control circuits includes the following steps:

[0006] S1, the coil of the latching relay is energized, and the normally open contact of the latching relay closes;

[0007] S2, when the closing control switch is closed, the closing output terminal of the microcomputer protection module outputs the closing control voltage, which cuts off the normally closed contact of the relay through the continuous closing signal, so that the closing coil of the circuit breaker is energized, and the main switch of the circuit breaker is closed, and the circuit breaker completes the closing.

[0008] S3, after the circuit breaker closes, the first normally open auxiliary contact of the circuit breaker closes, and the circuit containing the trip coil of the circuit breaker is in a closed state. At this time, the microcomputer protection module does not output the control voltage for tripping, and the trip coil of the circuit breaker is in a de-energized state. After the circuit breaker closes, the second normally closed auxiliary contact of the circuit breaker opens, the coil of the lockout relay is in a de-energized state, the normally open contact of the lockout relay opens, and the closing coil of the circuit breaker is in a de-energized state.

[0009] S4, when the trip output terminal of the microprocessor protection module outputs a trip voltage signal to energize the trip coil of the circuit breaker, the main switch of the circuit breaker is in the open state, and the circuit breaker completes the trip.

[0010] Furthermore, after the circuit breaker completes the trip, the circuit breaker is in a de-energized state. The first normally open auxiliary contact of the circuit breaker opens, the second normally closed auxiliary contact of the circuit breaker closes, the coil of the lockout relay is energized, and the normally open contact of the lockout relay closes.

[0011] Furthermore, in step S3, after the circuit breaker is closed, the fourth normally open auxiliary contact of the circuit breaker closes, and the closing output terminal outputs a closing control voltage, which is also output to the coil of the continuous closing signal disconnection relay connected in series with the fourth normally open auxiliary contact. After the coil of the continuous closing signal disconnection relay is energized, the normally closed contact of the continuous closing signal disconnection relay is opened.

[0012] Furthermore, it also includes the positive and negative terminals of the secondary power supply, the main switch connected in series with the primary bus, the current transformer connected to the bus, the current sensing input terminal of the microprocessor protection module connected to the current transformer, the trip output terminal of the microprocessor protection module connected to one end of the first normally open auxiliary contact, the other end of the first normally open auxiliary contact connected to one end of the trip coil, the other end of the trip coil connected to the negative terminal of the secondary power supply, and the closing control switch connected to the positive terminal of the secondary power supply and the closing input terminal of the microprocessor protection module.

[0013] The branch formed by the coil of the lockout relay and the second normally closed auxiliary contact connected in series is connected to the positive and negative terminals of the secondary power supply, respectively; the closing output terminal of the microprocessor protection module is connected to one end of the normally closed contact of the continuous closing signal cut-off relay, the other end of the normally closed contact of the continuous closing signal cut-off relay is connected to one end of the normally open contact of the lockout relay, the other end of the normally open contact of the lockout relay is connected to one end of the closing coil, the other end of the closing coil is connected to the negative terminal of the secondary power supply, and the other end of the coil of the continuous closing signal cut-off relay is connected to the negative terminal of the secondary power supply.

[0014] Furthermore, the circuit breaker also includes a third normally closed auxiliary contact, which is connected in series between the first selection connection terminal and the normally open contact of the lockout relay.

[0015] Furthermore, it also includes a display power relay and a cabinet door locking relay. The two ends of the coil of the display power relay are connected to the positive and negative terminals of the secondary power supply, respectively. One end of the normally open contact of the display power relay is connected to the positive terminal of the secondary power supply, and the other end of the normally open contact of the display power relay is connected to one end of the coil of the cabinet door locking relay. The other end of the coil of the cabinet door locking relay is connected to the negative terminal of the secondary power supply.

[0016] Furthermore, it also includes a handcart test position limit switch, one end of which is connected to the positive terminal of the secondary power supply, and the other end of which is connected to the second normally closed auxiliary contact.

[0017] Furthermore, it also includes a trolley working position limit switch, one end of which is connected to the positive terminal of the secondary power supply, and the other end of which is connected to the second normally closed auxiliary contact.

[0018] This invention connects the normally closed contact of a continuous closing signal cut-off relay in series in the closing circuit, and connects the coil of the continuous closing signal cut-off relay to the fourth normally open auxiliary contact of the circuit breaker. Therefore, when the coil of the continuous closing signal cut-off relay is energized, the normally closed contact of the relay opens, thereby cutting off the voltage supply to the closing coil. Even if the closing control switch remains closed due to misoperation or sticking together due to adhesive, the closing coil will not continue to be energized. When the closing output terminal of the microprocessor protection module no longer outputs control voltage, the coil of the continuous closing signal cut-off relay is de-energized, and the normally closed contact of the relay closes again. When the circuit overcurrent requires the circuit breaker to trip, the microprocessor protection module outputs a voltage signal through the trip output terminal. Since the circuit where the circuit breaker's trip coil is located is closed when the circuit is closed, the trip coil is energized, thereby putting the main switch of the circuit breaker in the open state. Therefore, this invention can not only avoid the circuit continuously sending a closing signal to the circuit breaker after the circuit is closed, but also automatically trip the circuit breaker. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the primary circuit structure for the tripping and closing control method of electrical equipment control circuit.

[0020] Figure 2 This is a schematic diagram of the secondary circuit structure for the tripping and closing control method of electrical equipment control circuit.

[0021] Figure 3 This is a schematic diagram showing how a circuit breaker can switch from being closed to being tripped as needed.

[0022] Figure 4This is a schematic diagram showing how a circuit breaker switches to closing mode as needed after tripping.

[0023] The markings in the attached diagram are as follows: Current transformer A, primary bus M, main switch DL, trip coil TQ, closing coil HQ, first normally open auxiliary contact QF1, second normally closed auxiliary contact QF2, third normally closed auxiliary contact QF3, fourth normally open auxiliary contact QF4, secondary power supply positive terminal +KM, secondary power supply negative terminal -KM, microcomputer protection module U, closing control switch K1, trip control switch K2, microcomputer protection module U, current sensing input terminal XT1, trip output terminal XT2, closing input terminal XT3, closing output terminal XT4, lockout relay coil Y1, lockout relay normally open contact Y11, continuous closing signal cutoff relay coil K0, continuous closing signal cutoff relay normally closed contact K11, display power relay coil HL, display power relay normally open contact HL1, cabinet door lockout relay coil DS, handcart test position limit switch S8, handcart working position limit switch S9. Detailed Implementation

[0024] like Figures 1 to 4 As shown, the tripping and closing control circuit of the electrical equipment of the present invention includes a circuit breaker, a current transformer A, a primary bus M, a secondary power supply positive terminal +KM, a secondary power supply negative terminal -KM, a microcomputer protection module U, a closing control switch K1, a tripping control switch K2, a blocking relay, and a continuous closing signal cutoff relay. The following is a detailed description of each part and the relationship between them.

[0025] The circuit breaker includes a main switch DL, a trip coil TQ for the circuit breaker, a closing coil HQ for the circuit breaker, a first normally open auxiliary contact QF1, and a second normally closed auxiliary contact QF2. The main switch DL is connected in series with the primary bus M, and the current transformer A is connected to the bus M.

[0026] The microprocessor protection module U is model PMF702A. Its current sensing input terminal XT1 is connected to current transformer A. Its trip output terminal XT2 is connected to one end of the first normally open auxiliary contact QF1, and the other end of QF1 is connected to one end of the trip coil TQ. The other end of the trip coil TQ is connected to the negative terminal -KM of the secondary power supply. The closing control switch K1 is connected to the positive terminal +KM of the secondary power supply and the closing input terminal XT3 of the microprocessor protection module U. The trip control switch K2 is connected to the positive terminal +KM of the secondary power supply and the trip input terminal XT5 of the microprocessor protection module U. Both closing and trip control switches are push-button switches with a self-resetting function.

[0027] The locking relay has a coil Y1 and a normally open contact Y11, and the continuous closing signal cut-off relay has a coil K0 and a normally closed contact K11. The branch formed by the coil Y1 of the locking relay and the second normally closed auxiliary contact QF2 connected in series is connected to the positive terminal +KM and the negative terminal -KM of the secondary power supply, respectively.

[0028] The closing output terminal XT4 of the microprocessor protection module U is connected to one end of the normally closed contact K11 of the continuous closing signal cut-off relay. The other end of the normally closed contact K11 of the continuous closing signal cut-off relay is connected to one end of the normally open contact Y11 of the lockout relay. The other end of the normally open contact Y11 of the lockout relay is connected to one end of the closing coil HQ. The other end of the closing coil HQ is connected to the negative terminal -KM of the secondary power supply.

[0029] In this embodiment, the circuit breaker also includes a third normally closed auxiliary contact QF3, which is connected in series between the first selection connection terminal 1 and the normally open contact Y11 of the lockout relay.

[0030] In this embodiment, the circuit breaker also includes a fourth normally open auxiliary contact QF4. One end of the fourth normally open auxiliary contact QF4 is connected to one end of the normally closed contact K11 of the continuous closing signal cut-off relay, and the other end of the fourth normally open auxiliary contact QF4 is connected to the closing output terminal XT4 of the microcomputer protection module U.

[0031] It should be noted that since the first normally open auxiliary contact QF1, the second normally closed auxiliary contact QF2, the third normally closed auxiliary contact QF3, and the fourth normally open auxiliary contact QF4 are all auxiliary contacts of the circuit breaker body, although the relevant coils belonging to the circuit breaker body are not shown in the figure, the operating principle of these contacts is the same as that of a conventional relay. That is, for the first normally open auxiliary contact QF1 and the fourth normally open auxiliary contact QF4, when the circuit breaker is de-energized, the first normally open auxiliary contact QF1 and the fourth normally open auxiliary contact QF4 are in the open state, and when the circuit breaker is energized, the first normally open auxiliary contact QF1 and the fourth normally open auxiliary contact QF4 are in the closed state. For the third normally closed auxiliary contact QF3 and the fourth normally open auxiliary contact QF4, when the circuit breaker is de-energized, the third normally closed auxiliary contact QF3 and the fourth normally open auxiliary contact QF4 are in the closed state, and when the circuit breaker is energized, the third normally closed auxiliary contact QF3 and the fourth normally open auxiliary contact QF4 are in the open state.

[0032] The trip and close control circuit of this embodiment also includes a display power relay and a cabinet door lock relay. The display power relay is used to display the connection status of the positive terminal +KM and the negative terminal -KM of the secondary power supply. The cabinet door lock relay is installed on the cabinet door of the secondary electrical cabinet and is used to lock or open the cabinet door.

[0033] The two ends of the coil HL of the display power relay are connected to the positive terminal +KM and the negative terminal -KM of the secondary power supply, respectively. One end of the normally open contact HL1 of the display power relay is connected to the positive terminal +KM of the secondary power supply. The other end of the normally open contact HL1 of the display power relay is connected to one end of the coil DS of the cabinet door locking relay. The other end of the coil DS of the cabinet door locking relay is connected to the negative terminal -KM of the secondary power supply.

[0034] When the cabinet door is closed, the switch 3ZK (usually an air switch) on the positive +KM and negative -KM lines of the secondary power supply closes, allowing the secondary power supply to output voltage. Since the coil HL of the display power relay is directly connected in series between the positive +KM and negative -KM lines, the coil HL is energized, causing the normally open contact HL1 of the display power relay to close. This energizes the coil DS of the cabinet door locking relay, and the cabinet door lock (not shown in the diagram) associated with the cabinet door locking relay is locked, preventing the cabinet door from opening. When switch 3ZK is open, the coil HL of the display power relay is de-energized, the normally open contact HL1 of the display power relay opens, the coil DS of the cabinet door locking relay is de-energized, and the cabinet door lock associated with the cabinet door locking relay is unlocked, allowing the cabinet door to open.

[0035] The trip and close control circuit of this embodiment also includes a handcart test position limit switch S8. One end of the handcart test position limit switch S8 is connected to the positive terminal +KM of the secondary power supply, and the other end of the handcart test position limit switch S8 is connected to the second normally closed auxiliary contact QF2.

[0036] The trip and close control circuit of this embodiment also includes a handcart working position limit switch S9. One end of the handcart working position limit switch S9 is connected to the positive terminal +KM of the secondary power supply, and the other end of the handcart working position limit switch S9 is connected to the second normally closed auxiliary contact QF2.

[0037] Since most components in the above circuit are mounted on the handcart, this circuit includes a test position and a working position for the handcart. A test position limit switch S8 is installed at the test position. When the handcart is moved to the test position, it is not fully pushed into the electrical cabinet, keeping the test position limit switch S8 in the ON state. Operating the closing and opening functions in the test position allows observation of whether the operation of each contact is correct. After confirming that there are no problems through testing, the handcart can be fully pushed into the cabinet to reach the working position. At this time, the test position limit switch S8 is in the OFF state, and the working position limit switch S9 is in the ON state.

[0038] The working process of this invention is as follows:

[0039] like Figure 2 When switch 3ZK is closed, the coil Y1 of the interlocking relay is energized, and the normally open contact Y11 of the interlocking relay closes. This causes the closing control switch K1 to close, and the closing output terminal XT4 of the microprocessor protection module U outputs a closing control voltage, such as 220V. The closing control voltage output by the closing output terminal XT4 sequentially cuts off the normally closed contact K11 and the third normally closed auxiliary contact QF3 of the continuous closing signal, energizing the closing coil HQ. This causes the circuit breaker to close, the main switch DL to close, and the transformer connected to the primary bus M to be energized and operated.

[0040] After the circuit breaker closes, the first normally open auxiliary contact QF1 closes, and the circuit containing the trip coil TQ is closed. However, since the microprocessor protection module U does not output control voltage for tripping at this time, the trip coil TQ is de-energized. After the circuit breaker closes, the second normally closed auxiliary contact QF2 opens, and the coil Y1 of the lockout relay is de-energized, thus the normally open contact Y11 of the lockout relay is open. After the circuit breaker closes, the third normally closed auxiliary contact QF3 opens, and the closing coil HQ is de-energized.

[0041] After the circuit breaker closes, the fourth normally open auxiliary contact QF4 of the circuit breaker closes. However, because the closing output terminal XT4 of the microprocessor protection module U outputs control voltage at this time, the coil K0 of the continuous closing signal cut-off relay is energized, causing the normally closed contact K11 of the continuous closing signal cut-off relay to open, thereby cutting off the voltage supply to the closing coil HQ. Even if the closing control switch K1 remains closed due to misoperation or is stuck together by adhesive, the closing coil HQ will not continue to be energized. When the closing output terminal XT4 of the microprocessor protection module U no longer outputs control voltage, the coil K0 of the continuous closing signal cut-off relay is de-energized, and the normally closed contact K11 of the continuous closing signal cut-off relay returns to the closed state.

[0042] Current transformer A provides the sampled current signal to microprocessor protection module U. Microprocessor protection module U determines whether the current on the primary bus M exceeds the set threshold, for example, the set threshold is 50A. If it exceeds this value, it is determined that an overcurrent has occurred on the primary side. At this time, microprocessor protection module U controls the circuit breaker to open. Microprocessor protection module U outputs a trip voltage signal through the trip output terminal XT2. The voltage of the trip voltage signal is 220V. Since the circuit where the trip coil TQ is located is in a closed state, the trip coil TQ is energized, thereby causing the main switch DL of the circuit breaker to be in an open state.

[0043] The tripping process described above may not be an overcurrent self-protection trip. For example, it can also be achieved by closing the trip control switch K2, thereby outputting a voltage signal from the microprocessor protection module U through the trip output terminal XT2. Since the circuit containing the trip coil TQ is in a closed state, the trip coil TQ is energized, thus causing the main switch DL of the circuit breaker to be in an open state. That is, this tripping is a manual tripping operation mode.

[0044] like Figure 4 As shown, after the main switch DL is opened, the circuit breaker loses power as a whole. The first normally open auxiliary contact QF1 and the fourth normally open auxiliary contact QF4 are in the open state, the trip coil TQ is in the de-energized state, the second normally closed auxiliary contact QF2 and the third normally closed auxiliary contact QF3 are in the closed state, the circuit containing the coil Y1 of the lockout relay is energized, and the normally open contact Y11 of the lockout relay is closed, thus returning to the state of waiting to close.

Claims

1. A tripping and closing control method for electrical equipment control circuits, characterized in that, Includes the following steps: S1, the coil (Y1) of the latching relay is energized, and the normally open contact (Y11) of the latching relay is closed; S2, when the closing control switch (K1) is closed, the closing output terminal (XT4) of the microprocessor protection module (U) outputs the closing control voltage and cuts off the normally closed contact (K11) of the relay through the continuous closing signal, so that the closing coil (HQ) of the circuit breaker is energized, and the main switch (DL) of the circuit breaker is closed, and the circuit breaker completes the closing. S3, after the circuit breaker closes, the first normally open auxiliary contact (QF1) of the circuit breaker closes, and the circuit containing the trip coil (TQ) of the circuit breaker is in a closed state. At this time, the microprocessor protection module (U) does not output the control voltage for tripping, and the trip coil (TQ) of the circuit breaker is in a de-energized state. After the circuit breaker closes, the second normally closed auxiliary contact (QF2) of the circuit breaker opens, the coil (Y1) of the lockout relay is in a de-energized state, the normally open contact (Y11) of the lockout relay opens, and the closing coil (HQ) of the circuit breaker is in a de-energized state. S4, when the trip output terminal (XT2) of the microprocessor protection module (U) outputs a trip voltage signal to energize the trip coil (TQ) of the circuit breaker, the main switch (DL) of the circuit breaker is in the open state, and the circuit breaker completes the trip; In step S3, after the circuit breaker is closed, the fourth normally open auxiliary contact (QF4) of the circuit breaker closes, and the closing output terminal (XT4) outputs the closing control voltage to the coil (K0) of the continuous closing signal disconnection relay connected in series with the fourth normally open auxiliary contact (QF4). After the coil (K0) of the continuous closing signal disconnection relay is energized, the normally closed contact (K11) of the continuous closing signal disconnection relay is opened.

2. The tripping and closing control method for electrical equipment control circuits according to claim 1, characterized in that, After the circuit breaker completes the trip, the circuit breaker is in a de-energized state. The first normally open auxiliary contact (QF) of the circuit breaker opens, the second normally closed auxiliary contact (QF2) of the circuit breaker closes, the coil (Y1) of the lockout relay is energized, and the normally open contact (Y11) of the lockout relay closes.

3. The tripping and closing control method for electrical equipment control circuits according to claim 1, characterized in that, It also includes the positive terminal (+KM) and negative terminal (-KM) of the secondary power supply, the main switch (DL) connected in series with the primary bus (M), the current transformer (A) working with the bus (M), the current sensing input terminal (XT1) of the microprocessor protection module (U) connected to the current transformer (A), the trip output terminal (XT2) of the microprocessor protection module (U) connected to one end of the first normally open auxiliary contact (QF1), the other end of the first normally open auxiliary contact (QF1) connected to one end of the trip coil (TQ), the other end of the trip coil (TQ) connected to the negative terminal (-KM) of the secondary power supply, and the closing control switch (K1) connected to the positive terminal (+KM) of the secondary power supply and the closing input terminal (XT3) of the microprocessor protection module (U); The branch formed by the coil (Y1) of the lockout relay and the second normally closed auxiliary contact (QF2) connected in series is connected to the positive terminal (+KM) and the negative terminal (-KM) of the secondary power supply, respectively; the closing output terminal (XT4) of the microcomputer protection module (U) is connected to one end of the normally closed contact (K11) of the continuous closing signal cutoff relay, the other end of the normally closed contact (K11) of the continuous closing signal cutoff relay is connected to one end of the normally open contact (Y11) of the lockout relay, the other end of the normally open contact (Y11) of the lockout relay is connected to one end of the closing coil (HQ), the other end of the closing coil (HQ) is connected to the negative terminal (-KM) of the secondary power supply, and the other end of the coil (K0) of the continuous closing signal cutoff relay is connected to the negative terminal (-KM) of the secondary power supply.

4. The tripping and closing control method for electrical equipment control circuits according to claim 3, characterized in that, The circuit breaker also includes a third normally closed auxiliary contact (QF3), which is connected in series between the first selection connection terminal (1) and the normally open contact (Y11) of the lockout relay.

5. The tripping and closing control method for electrical equipment control circuits according to claim 3, characterized in that, It also includes a display power relay and a cabinet door lock relay. The two ends of the coil (HL) of the display power relay are connected to the positive terminal (+KM) and the negative terminal (-KM) of the secondary power supply, respectively. One end of the normally open contact (HL1) of the display power relay is connected to the positive terminal (+KM) of the secondary power supply, and the other end of the normally open contact (HL1) of the display power relay is connected to one end of the coil (DS) of the cabinet door lock relay. The other end of the coil (DS) of the cabinet door lock relay is connected to the negative terminal (-KM) of the secondary power supply.

6. The tripping and closing control method for electrical equipment control circuits according to claim 3, characterized in that, It also includes a handcart test position limit switch (S8), one end of which is connected to the positive terminal (+KM) of the secondary power supply, and the other end of which is connected to the second normally closed auxiliary contact (QF2).

7. The tripping and closing control method for electrical equipment control circuits according to claim 3, characterized in that, It also includes a trolley working position limit switch (S9), one end of which is connected to the positive terminal (+KM) of the secondary power supply, and the other end of which is connected to the second normally closed auxiliary contact (QF2).

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