Switch cabinet control loop fault diagnosis terminal

Abstract

The utility model relates to the technical field of switch cabinets, in particular to a switch cabinet control loop fault diagnosis terminal, which is characterized in that a central processing unit (MCU) is respectively connected with an on-off input circuit, a relay output circuit, a turn-off isolation circuit and an analog direct-current voltage sampling circuit, the on-off input circuit is connected with the turn-off isolation circuit, and the analog direct-current voltage sampling circuit is connected with the relay output circuit. And the working power supply circuit is used for providing a working power supply for the central processing unit MCU, the switching value input circuit, the turn-off isolation circuit, the relay output circuit and the analog DC voltage sampling circuit. The utility model has the advantages that the fault diagnosis of the control loop of the switch cabinet is modularized, so that the wiring operation in the diagnosis operation process is simple, and the problems of long maintenance time, high potential safety hazard, complex wiring and operation and the like of the existing switch cabinet are solved; a to-be-tested node in the switch cabinet control loop is connected with the switching value input circuit through a terminal, and a maintainer can observe the on-off state of the to-be-tested node in the switch cabinet control loop through the HMI human-computer interaction screen.

Description

Technical Field

[0001] This utility model relates to the field of switchgear technology, and in particular to a fault diagnosis terminal for switchgear control circuit. Background Technology

[0002] The switchgear control circuit is used for the closing and opening actions of the distribution switches within the switchgear. The safe operation of the switchgear control circuit is directly related to the safety of the power distribution system and power grid. Currently, fault detection in the switchgear control circuit relies on manual measurement by maintenance personnel. This involves using a multimeter to test each node in the control circuit, such as circuit breaker contacts, relay contacts, and control circuit nodes, point by point and segment by segment. This method is complex, limited by the maintenance personnel's skill level, time-consuming, and poses significant safety risks, urgently requiring improvement. Utility Model Content

[0003] The purpose of this invention is to provide a fault diagnosis terminal for switchgear control circuits, which solves the problems of long maintenance time, high safety hazards, and complex wiring and operation of existing switchgear.

[0004] To achieve the above objectives, this utility model employs the following technical solution:

[0005] A fault diagnosis terminal for switchgear control circuit includes a central processing unit (MCU), a power supply circuit, a digital input circuit, a relay output circuit, a turn-off isolation circuit, and an analog DC voltage sampling circuit. The MCU is connected to the digital input circuit, the relay output circuit, the turn-off isolation circuit, and the analog DC voltage sampling circuit. The digital input circuit is connected to the turn-off isolation circuit. The power supply circuit provides power to the MCU, the digital input circuit, the turn-off isolation circuit, the relay output circuit, and the analog DC voltage sampling circuit.

[0006] The power supply circuit includes an isolated 12V circuit, a 3.3V circuit, a 12V circuit, and a 5V circuit. The isolated 12V circuit provides 12V power to the digital input circuit. The 3.3V circuit provides 3.3V power to the turn-off isolated circuit and the central processing unit (MCU). The 12V circuit provides 12V power to the relay output circuit. The 5V circuit provides 5V power to the analog DC voltage sampling circuit.

[0007] The number of shut-off isolation circuits is ≥1. Each shut-off isolation circuit includes a DC / DC converter PR and a MOS relay U. The DC / DC converter PR is used to convert the 3.3V voltage to 12V. The positive terminal of the 12V is connected to one end of the output terminal of the MOS relay U. The other end of the output terminal of the MOS relay U is connected to pin 1 of terminal CN through a diode. One end of the input terminal of the MOS relay U is connected to 3.3V. The other end of the input terminal of the MOS relay U is connected to pin OPG of the central processing unit MCU through a resistor.

[0008] Pin 2 of terminal CN is connected to the digital input circuit;

[0009] The 12V negative terminal is connected to the digital input circuit.

[0010] The digital input circuit includes an optocoupler ISO, with at least one optocoupler ISO. One end of the input terminal of each optocoupler ISO is connected to pin 2 of terminal CN of the optocoupler ISO through a resistor, and the other end of the input terminal of each optocoupler ISO is connected to the 12V negative terminal of the turn-off isolation circuit through a diode. One end of the output terminal of each optocoupler ISO is connected to pin 1 of the central processing unit MCU, and the other end of the output terminal of each optocoupler ISO is grounded.

[0011] The relay output circuit includes a Darlington driver chip U15. The input terminals of the Darlington driver chip U15 are connected to the pins of the central processing unit MCU, and the output terminals of the Darlington driver chip U15 are connected to the coil of the relay RL. The normally open contacts of the relay RL are connected to the pin NO of the terminal CN.

[0012] The analog DC voltage sampling circuit includes a differential voltage output circuit and a voltage follower circuit connected in sequence. The differential voltage output circuit includes a differential input circuit and an operational amplifier circuit. An anti-parallel diode is connected between the differential input circuit and the operational amplifier circuit. The input terminal of the differential input circuit is connected to the detection signal of the switch cabinet control circuit. The output terminal of the voltage follower circuit is connected to the DC pin of the central processing unit MCU. The operational amplifier circuit includes an operational amplifier, and the voltage follower circuit includes a voltage follower.

[0013] One end of the differential input circuit includes resistor one, the input terminal of which is connected to the positive terminal of the detection signal of the switchgear control circuit. The other end of the differential input circuit includes resistor two, the input terminal of which is connected to the negative terminal of the detection signal of the switchgear control circuit.

[0014] It also includes an isolated RS485 communication circuit, with the central processing unit (MCU) connected to the isolated RS485 communication circuit.

[0015] The central processing unit (MCU) is an ATXMEGA128A3U.

[0016] Compared with the prior art, the beneficial effects of this utility model are:

[0017] 1. The fault diagnosis device for the switchgear control circuit is made simple, making the wiring operation during the diagnosis process simple, ensuring the safety and reliability of maintenance personnel, and solving the problems of long maintenance time, high safety hazards (especially many exposed live parts), and complicated wiring and operation of existing switchgear.

[0018] 2. The node under test in the switch cabinet control circuit is connected to the switch input circuit through terminals. Maintenance personnel can observe the on / off status of the node under test in the switch cabinet control circuit through the HMI human-machine interface, which shortens maintenance time and saves time and effort.

[0019] 3. Built-in power supply circuit, no additional power supply required;

[0020] 4. A switch input circuit is used to achieve electrical isolation between the live equipment and the inspection personnel, ensuring the personal safety of the maintenance personnel;

[0021] 5. By utilizing the opening and closing action of each relay in the relay output circuit, the opening and closing action of a certain equipment node in the switch cabinet control circuit can be manually simulated. This eliminates the need for maintenance personnel to manually open and close a certain piece of equipment, ensuring the safety of the testing operation and enabling continuous diagnostic measurements.

[0022] 6. It adopts a shut-off isolation circuit to avoid mutual interference between detection channels, and has a simple structure and is easy to operate. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the fault diagnosis terminal structure for the switchgear control circuit.

[0024] Figure 2 This is a schematic diagram of the working power supply circuit.

[0025] Figure 3 This is a schematic diagram of a switchable isolation circuit.

[0026] Figure 4 This is a schematic diagram of a digital input circuit.

[0027] Figure 5 This is a schematic diagram of the central processing unit (MCU).

[0028] Figure 6 This is a schematic diagram of the relay output circuit.

[0029] Figure 7 This is a schematic diagram of the analog DC voltage sampling circuit.

[0030] Figure 8 This is a schematic diagram of an isolated RS485 communication circuit. Detailed Implementation

[0031] The present invention will now be described in detail with reference to the accompanying drawings. However, it should be noted that the implementation of the present invention is not limited to the following embodiments.

[0032] The following embodiments are implemented based on the technical solution of this utility model, providing detailed implementation methods and specific operation processes. However, the protection scope of this utility model is not limited to the following embodiments. Unless otherwise specified, the methods used in the following embodiments are conventional methods.

[0033] Example 1

[0034] See Figure 1 A fault diagnosis terminal for switchgear control circuits includes a central processing unit (MCU), a power supply circuit, a digital input circuit, a relay output circuit, a turn-off isolation circuit, and an analog DC voltage sampling circuit. The MCU uses an ATXMEGA128A3U chip. Figure 5 Alternatively, other chips can be used. The central processing unit (MCU) is connected to the digital input circuit, the relay output circuit, the shut-off isolation circuit, and the analog DC voltage sampling circuit, respectively. The digital input circuit is connected to the shut-off isolation circuit. The power supply circuit is used to provide power to the central processing unit (MCU), the digital input circuit, the shut-off isolation circuit, the relay output circuit, and the analog DC voltage sampling circuit.

[0035] See Figure 2The power supply circuit includes a 220V input circuit, a short-circuit protection circuit, a rectifier and filter circuit, a capacitor discharge circuit, a spike absorption circuit, a DC / DC flyback converter circuit, a power indicator circuit, an isolation 12V circuit, a 3.3V circuit, a 12V circuit, and a 5V circuit. The isolation 12V circuit provides 12V power to the digital input circuit. The 3.3V circuit provides 3.3V power to the turn-off isolation circuit and the central processing unit (MCU). The 12V circuit provides 12V power to the relay output circuit. The 5V circuit provides 5V power to the analog DC voltage sampling circuit. The 220V input circuit, short-circuit protection circuit, rectifier and filter circuit, capacitor discharge circuit, spike absorption circuit, and DC / DC flyback converter circuit are connected in sequence for... The circuit provides power to isolated 12V, 3.3V, 12V, and 5V circuits. The 220V input circuit includes terminal CN10. The short-circuit protection circuit includes a resettable fuse FS1. The rectifier and filter circuit includes a rectifier bridge BR1 and an electrolytic capacitor C2A. The capacitor discharge circuit includes discharge resistors R1A and R1B. The AC 220V working power supply input from terminal CN10, after short-circuit protection provided by the resettable fuse FS1, enters the rectifier and filter circuit composed of rectifier bridge BR1 and electrolytic capacitor C2A. The DC / DC flyback converter circuit includes a switching power supply control chip U20. The switching power supply control chip U20 drives a high-frequency transformer TR1 to form a flyback switching power supply to complete power isolation and voltage reduction. Z5 and D77 are leakage inductance spike voltage absorption circuits for transformer TR1A. The coil-induced voltage between pins 9 and 10 of transformer TR1A is rectified and filtered into a 12V DC voltage by fast recovery diodes D71, C10, and C11. This voltage is fed into resistors R80 and R81 and Zener diode Z6 to form a 12V circuit, which is then regulated by optocoupler IOS100 for stable output. One path of the 12V output goes through a three-terminal linear regulator VR3 to output 5VDC, while the other path is stepped down to 3.3VDC by a buck circuit consisting of VR1, D78, L2, and C14. The coil-induced voltage between pins 6 and 7 of transformer TR1C is rectified and filtered into another isolated 12VDC voltage by fast recovery diodes D71 and C16. Resistor R100, C22, and voltage reference chip Q3 are used to generate a 2.5VDC reference voltage, which is used to form an analog DC voltage sampling circuit. Resistor R83 and LED form a power indicator circuit, which illuminates when the power supply is working.

[0036] See Figure 3The number of shut-off isolation circuits is ≥1. Taking one shut-off isolation circuit as an example, each shut-off isolation circuit includes a DC / DC converter PR4 and a MOS relay U4. The DC / DC converter PR4 converts the 3.3V voltage to 12V. The positive terminal of PR4 is connected to one end of the output terminal of MOS relay U4. The other end of the output terminal of MOS relay U4 is connected to pin 1 of terminal CN04 through diode D53. One end of the input terminal of MOS relay U4 is connected to 3.3V. The other end of the input terminal of MOS relay U4 is connected to pin OP of the central processing unit MCU through a resistor. G4 connection; pins 2, 3, and 4 of terminal CN04 are connected to pins IN10, IN11, and IN12 of the digital input circuit, respectively; the 12V negative terminal 12G4 is connected to the digital input circuit; the DC / DC converter PR4 can convert 3.3VDC voltage to one isolated 12VDC. The MCU pulls down pin OPG8 to turn on the MOS relay, causing the +12V4 voltage to be output to pin 1 of terminal CN04 to power the digital detection circuit of the switch cabinet. When detection is not required, OPG4 can be raised to turn off the output of MOS relay U4 to prevent this voltage from affecting other detection channels.

[0037] See Figure 4 The digital input circuit includes an optocoupler ISO, with at least one optocoupler ISO. Taking three optocouplers ISO as an example, they are optocoupler ISO10, optocoupler ISO11, and optocoupler ISO12. One end of the input terminal of optocoupler ISO10 / ISO11 / ISO12 is connected to pin 2 / pin 3 / pin 4 of terminal CN10 of optocoupler ISO through resistors R10 / R11 / R12. The other end of the input terminal of optocoupler ISO10 / ISO11 / ISO12 is connected to the 12V negative terminal 12G4 of the turn-off isolation circuit through diodes D10 / D11 / D12. One end of the output terminal of optocoupler ISO10 / ISO11 / ISO12 is connected to pin I10 / pin I11 / pin I12 of the central processing unit MCU. The other end of the output terminal of optocoupler ISO10 / ISO11 / ISO12 is grounded.

[0038] See Figure 6 The relay output circuit includes a Darlington driver chip U15. The input terminals of the Darlington driver chip U15 are connected to pins K1-K8 of the central processing unit MCU, and the output terminals of the Darlington driver chip U15 are connected to the coils of relays RL1-RL8. The normally open contacts of relays RL1-RL8 are connected to pins NO1-NO8 of terminal CN12.

[0039] See Figure 7The analog DC voltage sampling circuit includes two identical circuits. Each circuit includes a differential voltage output circuit and a voltage follower circuit connected in sequence. The differential voltage output circuit includes a differential input circuit and an operational amplifier circuit. Anti-parallel diodes D60A / D60B are connected between the differential input circuit and the operational amplifier circuit. The input terminal of the differential input circuit is connected to the detection signal DC1+ / DC1- of the switchgear control circuit, and the output terminal of the voltage follower circuit is connected to the DC1 pin of the central processing unit MCU. One end of the differential input circuit includes a resistor, the input of which is connected to the positive terminal DC1+ of the switchgear control circuit detection signal. The other end of the differential input circuit includes a resistor, the input of which is connected to the negative terminal DC1- of the switchgear control circuit detection signal. Resistor 1 includes resistors R40, R41, and R42 connected in series, and resistor 2 includes resistors R43, R44, and R45 connected in series. The operational amplifier circuit includes an operational amplifier U13B, and the voltage follower circuit includes a voltage follower.

[0040] Work process:

[0041] This device uses an aviation connector to interface with the test interface installed on the switchgear. The simulated DC voltage sampling circuit is connected to the positive and negative bus terminals of the switchgear control circuit. The simulated DC voltage sampling circuit is used to detect the DC operating voltage of the bus and determine whether the switchgear's control power supply is within the acceptable voltage range. See [link / details]. Figure 5 ,See Figure 7 The output terminal DC1 of the simulated DC voltage sampling circuit is connected to pin DC1 of the central processing unit MCU. The control power supply of the switchgear is observed to be within the acceptable voltage range via the HMI (Human-Machine Interface) screen, allowing for continued diagnostic operations. The switch quantity detection circuit is connected to the nodes to be tested in the switchgear control circuit (such as circuit breaker contacts and relay contacts) via terminals (e.g., pins 1 and 2 of terminal CN08) to complete the connection and disconnection of each switchgear control circuit. The relay output circuit is connected to the switchgear control circuit. The opening and closing actions of each relay in the relay output circuit are used to manually simulate the opening and closing actions of a certain node in the switchgear control circuit, achieving continuous diagnostic measurement. The test process and results are transmitted to the HMI screen for display via RS485 communication.

[0042] Example 2

[0043] In this embodiment, a switch cabinet control circuit fault diagnosis terminal is the same as in embodiment 1, but with the addition of an isolated RS485 communication circuit, and the central processing unit MCU is connected to the isolated RS485 communication circuit.

[0044] See Figure 8The isolated RS485 communication circuit includes two channels, both with identical structures. Taking one channel as an example, the isolated RS485 communication circuit includes an isolated RS485 chip U11. The isolated RS485 chip U11 is an isolated RS485 communication interface chip with internal electrical isolation circuitry, isolating the electrical connection between the left and right sides of the circuit and improving anti-interference capability. Pins 12 and 13 of the isolated RS485 chip U11 are connected to terminals CN09 via resettable fuses F1 and F2, respectively, for E485+ and E485. E485+ and E485- are the differential signals of RS485, which, through terminal CN09, realize a 2-wire differential communication bus. Resettable fuses F1 and F2 are used for current limiting protection. Pin 12 of the isolated RS485 chip U11 is grounded through resistor R60, and pin 13 of the isolated RS485 chip U11 is grounded through resistor R61. Resistors R60 and R61 are used to clamp the differential bus to a high level. TVS protection diode Z10 provides TVS overvoltage protection. When in receive mode (EXT_CTRL low level), the communication data on the bus is converted by U11 into a 3.3V voltage serial signal and connected to the MCU's USART input pin through pin EXT_RXD of the isolated RS485 chip U11. When in transmit mode (EXT_CTRL high level), the MCU's USART transmit data is sent through pin EXT_TXD. The communication data is converted by U11 and sent to the communication bus.

[0045] This invention modularizes the fault diagnosis device for switchgear control circuits, simplifying wiring operations during diagnosis and ensuring the safety and reliability of maintenance personnel. It solves problems such as long maintenance times, high safety hazards (especially with numerous exposed live parts), and complex wiring and operation in existing switchgear systems. The nodes under test in the switchgear control circuit are connected to the switch input circuit via terminals, allowing maintenance personnel to observe the on / off status of these nodes through an HMI (Human-Machine Interface), shortening maintenance time and saving time and effort. A built-in power supply circuit eliminates the need for an external power supply. The use of a switch input circuit achieves electrical isolation between live equipment and testing personnel, ensuring their safety. The opening and closing actions of each relay in the relay output circuit manually simulate the opening and closing actions of a specific device node in the switchgear control circuit, eliminating the need for maintenance personnel to operate the device while it is powered on, ensuring safe testing and enabling continuous diagnostic measurements. The use of a switchable isolation circuit avoids mutual interference between testing channels, resulting in a simple structure and convenient operation.

Claims

1. A fault diagnosis terminal for switchgear control circuits, characterized in that, It includes a central processing unit (MCU), a power supply circuit, a digital input circuit, a relay output circuit, a turn-off isolation circuit, and an analog DC voltage sampling circuit. The MCU is connected to the digital input circuit, the relay output circuit, the turn-off isolation circuit, and the analog DC voltage sampling circuit. The digital input circuit is connected to the turn-off isolation circuit. The power supply circuit provides power to the MCU, the digital input circuit, the turn-off isolation circuit, the relay output circuit, and the analog DC voltage sampling circuit.

2. The switchgear control circuit fault diagnostic terminal according to claim 1, characterized in that, The power supply circuit includes an isolated 12V circuit, a 3.3V circuit, a 12V circuit, and a 5V circuit. The isolated 12V circuit provides 12V power to the switch input circuit. The 3.3V circuit provides 3.3V power to the turn-off isolation circuit and the central processing unit (MCU). The 12V circuit provides 12V power to the relay output circuit. The 5V circuit provides 5V power to the analog DC voltage sampling circuit.

3. The switchgear control circuit fault diagnostic terminal according to claim 2, characterized in that, The number of the shut-off isolation circuits is ≥1. Each shut-off isolation circuit includes a DC / DC converter PR and a MOS relay U. The DC / DC converter PR is used to convert the 3.3V voltage to 12V. The positive terminal of the 12V is connected to one end of the output terminal of the MOS relay U. The other end of the output terminal of the MOS relay U is connected to pin 1 of terminal CN through a diode. One end of the input terminal of the MOS relay U is connected to 3.3V. The other end of the input terminal of the MOS relay U is connected to pin OPG of the central processing unit MCU through a resistor. Pin 2 of terminal CN is connected to the digital input circuit; The 12V negative terminal is connected to the digital input circuit.

4. The switchgear control circuit fault diagnostic terminal according to claim 3, characterized in that, The aforementioned digital input circuit includes an optocoupler ISO, with at least one optocoupler ISO. One end of the input terminal of each optocoupler ISO is connected to pin 2 of terminal CN of the optocoupler ISO via a resistor, and the other end of the input terminal of each optocoupler ISO is connected to the 12V negative terminal of the turn-off isolation circuit via a diode. One end of the output terminal of each optocoupler ISO is connected to pin 1 of the central processing unit MCU, and the other end of the output terminal of each optocoupler ISO is grounded.

5. The switchgear control circuit fault diagnostic terminal of claim 1, wherein, The relay output circuit includes a Darlington driver chip U15. The input terminals of the Darlington driver chip U15 are connected to the pins of the central processing unit MCU, and the output terminals of the Darlington driver chip U15 are connected to the coil of the relay RL. The normally open contacts of the relay RL are connected to the pin NO of the terminal CN.

6. The switchgear control circuit fault diagnostic terminal of claim 1, wherein, The analog DC voltage sampling circuit includes a differential voltage output circuit and a voltage follower circuit connected in sequence. The differential voltage output circuit includes a differential input circuit and an operational amplifier circuit. An anti-parallel diode is connected between the differential input circuit and the operational amplifier circuit. The input terminal of the differential input circuit is connected to the detection signal of the switch cabinet control circuit. The output terminal of the voltage follower circuit is connected to the DC pin of the central processing unit MCU. The operational amplifier circuit includes an operational amplifier, and the voltage follower circuit includes a voltage follower.

7. The switchgear control circuit fault diagnostic terminal of claim 6, wherein, One end of the differential input circuit includes resistor one, the input terminal of which is connected to the positive terminal of the detection signal of the switchgear control circuit. The other end of the differential input circuit includes resistor two, the input terminal of which is connected to the negative terminal of the detection signal of the switchgear control circuit.

8. The switchgear control circuit fault diagnostic terminal of claim 1, wherein, It also includes an isolated RS485 communication circuit, with the central processing unit (MCU) connected to the isolated RS485 communication circuit.

9. The switchgear control circuit fault diagnostic terminal of claim 1, wherein, The central processing unit MCU is an ATXMEGA128A3U.

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