CN114441949A - On-line monitoring device of circuit breaker and switch cabinet - Google Patents

Abstract

The present disclosure discloses an on-line monitoring device and a switch cabinet of a circuit breaker. The online monitoring device for a circuit breaker of the present disclosure includes a circuit breaker and a current acquisition unit. The current acquisition unit is integrated on an anti-jump control board inside the electrical anti-jump box. The anti-jump control board is provided with a plurality of external interfaces. The current of the gate coil, the current of the closing coil and the current of the energy storage motor are connected to the anti-jump control board through the external interface, and the current acquisition unit is electrically connected to the external interface of the current of the opening coil, the current of the closing coil and the current of the energy storage motor. , to collect the opening coil current, closing coil current and energy storage motor current of the circuit breaker.

Description

On-line monitoring device and switch cabinet of circuit breaker

technical field

The present disclosure relates to the field of electrical equipment, in particular to an on-line monitoring device of a circuit breaker and a switch cabinet.

Background technique

Switchgears are used in power systems such as the National Grid, and play the functions of switching, controlling and protecting electrical equipment in the power system. The circuit breaker is the most important component in the switch cabinet. On the one hand, it is used to control the opening and closing of the circuit, and on the other hand, it is used to protect the switch cabinet. When a fault occurs, the circuit breaker is automatically activated to quickly remove the faulty part from the power grid. Cut off to ensure the normal operation of the fault-free part of the grid.

The power Internet of Things is the development direction of the future power system. The state monitoring and data exchange of circuit breakers are an important part of the power Internet of Things. The circuit breakers of traditionally manufactured switchgear are generally not equipped with state monitoring devices, so it is generally necessary to modify the traditional switchgear and install corresponding monitoring devices. However, due to the complex electrical connections between the electrical components in the switchgear , any change to any part of the switch cabinet may affect the function of other parts, so how to collect the status data of the circuit breaker is a problem currently faced by the industry.

SUMMARY OF THE INVENTION

In order to solve the problem in the related art that the traditional switch cabinet is modified and installed, the monitoring device is faced with complicated modification work.

The present disclosure provides an on-line monitoring device for a circuit breaker, including:

circuit breakers; and

The current acquisition unit is integrated on the anti-jump control board inside the electrical anti-jump box, the anti-jump control board is provided with a plurality of external interfaces, the current of the opening coil, the current of the closing coil and the energy storage of the circuit breaker The motor current is connected to the anti-jump control board through the external interface, and the current acquisition unit is electrically connected to the external interface connected to the opening coil current, the closing coil current and the energy storage motor current to collect the circuit breaker The opening coil current, closing coil current and energy storage motor current.

Optionally, the online monitoring device further includes an acquisition module disposed on the anti-jump control board, the acquisition module includes the current acquisition unit, an analog-to-digital conversion unit electrically connected to the current acquisition unit, and a a processor electrically connected to the analog-to-digital conversion unit and a first wireless communication unit electrically connected to the processor;

The acquisition module further includes a plurality of expansion interfaces arranged on the anti-jump control board, and the current of the chassis vehicle motor of the circuit breaker is connected to the anti-jump control board through one of the expansion interfaces, and the current is collected. The unit is electrically connected to the extension interface for accessing the motor current of the chassis vehicle, so as to collect the motor current of the chassis vehicle.

Optionally, the current acquisition unit includes a plurality of on-board Hall current sensors, each on-board Hall current sensor is connected to the current of the opening coil, the current of the closing coil, the current of the energy storage motor and the current of the chassis car motor. One of the external interfaces or one of the expansion interfaces is connected to collect the current of the opening coil, the current of the closing coil, the current of the energy storage motor and the current of the chassis car motor.

Optionally, another expansion interface among the plurality of expansion interfaces is electrically connected with an angular displacement sensor that detects the rotation angle of the main shaft of the circuit breaker;

The expansion interface electrically connected with the angular displacement sensor is electrically connected with the analog-to-digital conversion unit, so as to convert the analog voltage signal collected by the angular displacement sensor into a digital signal.

Optionally, a plurality of the external interfaces are integrated on the same external interface module, and a plurality of expansion interfaces are integrated on the same expansion interface module.

Optionally, the online monitoring device further includes a wireless receiving module;

The on-line monitoring device further includes an acquisition module, which includes the current acquisition unit, an analog-to-digital conversion unit electrically connected to the current acquisition unit, a processor electrically connected to the analog-to-digital conversion unit, and a processor electrically connected to the current acquisition unit. The first wireless communication unit electrically connected to the processor, the processor processes the digital-to-analog converted current data, generates a current-time current waveform diagram, extracts characteristic values from the current waveform diagram, and converts the current waveform The map and the extracted feature values are sent to the wireless receiving module through the first wireless communication unit.

Optionally, the wireless receiving module includes a circuit board, a processing unit disposed on the circuit board, and a second wireless communication unit, and the second wireless communication unit communicates wirelessly with the first wireless communication unit to receive The current-time current waveform data and eigenvalue data of the current acquisition unit, the processing unit saves the waveform data as a standard COMTRADE format, saves the eigenvalue data as a report, and uses the wireless receiving module's network port as a report. The protocol of IEC103 is uploaded to the background diagnosis system.

Optionally, the on-line monitoring device further includes a plurality of wireless temperature sensors for monitoring circuit breaker contacts, contact arms, busbar junctions, and cable junctions, and the wireless receiving module is connected to each of the wireless temperature sensors. A wireless communication connection is made to receive temperature data collected by each of the wireless temperature sensors.

Optionally, the online monitoring device further includes an expansion module, and the expansion module is serially connected to the wireless receiving module;

The expansion module includes an expansion circuit board, a processor and an analog-to-digital conversion unit arranged on the expansion circuit board;

The expansion module has a plurality of interfaces, and the three-phase main circuit current and the grounding switch motor current are connected to the expansion module through the corresponding interfaces;

The online monitoring device further includes a main circuit current sensor for monitoring the three-phase main circuit current of the circuit breaker and an earthing switch current sensor for monitoring the motor current of the earthing switch, the main circuit current sensor being connected to the three-phase main circuit. The current interface is connected, the grounding switch current sensor is connected to the interface for accessing the motor current of the grounding switch, and the main loop current sensor and the grounding switch current sensor are located inside or outside the expansion module.

Optionally, the expansion module further includes a binary input detection unit and a binary input detection interface for detecting the opening and closing times of the circuit breaker, and the binary input detection interface is electrically connected to the secondary circuit of the switch cabinet through a wire. Get the switch signal;

The binary input detection unit is arranged inside the expansion module, the binary input detection unit includes a voltage divider circuit and a binary input sensor, and the expansion module detects the binary input sensor through serial communication. The binary input is transmitted to the wireless receiving module.

Optionally, the main loop current sensor and the grounding switch current sensor are open-type Hall current sensors, and the open-input sensor is an optical coupling sensor.

The present disclosure further provides a switch cabinet, comprising:

Cabinet, including circuit breaker room and low voltage room;

an electrical anti-jump box provided in the circuit breaker compartment, and

The above-mentioned on-line monitoring device for circuit breakers, the circuit breaker of the on-line monitoring device is arranged in the circuit breaker room, the current acquisition unit of the on-line monitoring device is arranged in the electrical anti-jump box, the The wireless receiving module is arranged in the low pressure chamber.

The technical solutions provided by the embodiments of the present disclosure may include the following beneficial effects:

The present disclosure provides an on-line monitoring device for a circuit breaker, including a circuit breaker and a current acquisition unit, the current acquisition unit is integrated on an anti-jump control board inside an electrical anti-jump box, and the anti-jump control board is provided with a plurality of external interfaces to open the circuit. The opening coil current, closing coil current and energy storage motor current of the device are connected to the anti-jump control board through the external interface, and the current acquisition unit is connected to the external interface connected to the opening coil current, closing coil current and energy storage motor current. Connect to collect the opening coil current, closing coil current and energy storage motor current of the circuit breaker. The present disclosure integrates the current acquisition unit on the anti-jump control board, and uses the opening coil current, the closing coil current and the energy storage motor current that were originally connected to the anti-jump control board to realize the anti-jump function, to obtain the relevant status data of the circuit breaker. Therefore, under the condition that the original mechanical structure and electrical secondary wiring structure of the circuit breaker are not changed, and the original electrical anti-jump function is maintained, the collection of relevant status data of the circuit breaker is realized, which is the most important part of the circuit breaker Operational status monitoring and diagnostic analysis provide data support. In addition, the structural modification of the present disclosure is small, rapid modification can be realized, and a lot of manpower, material resources and other modification costs are saved.

The present disclosure further provides a switch cabinet, which includes a cabinet body, an electrical anti-jump box arranged in a circuit breaker room, and an on-line monitoring device for the circuit breaker. The cabinet includes a circuit breaker room and a low-voltage room, the circuit breaker is arranged in the breaker room, the current acquisition unit of the online monitoring device is integrated in the electrical anti-jump box, and the wireless receiving module of the online monitoring device is arranged in the low-voltage room. Since the switchgear adopts the online monitoring device of the above circuit breaker, in order to realize the Internet of Things, the switchgear can be quickly modified, saving a lot of manpower, material resources and other modification costs.

It is to be understood that the foregoing general description and the following detailed description are exemplary only and do not limit the present disclosure.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure, and together with the description serve to explain the principles of the disclosure.

FIG. 1 is a schematic structural diagram of a switch cabinet according to an exemplary embodiment of the present disclosure.

FIG. 2 is a schematic structural diagram of an anti-jump control board inside the anti-jump box of the present disclosure.

FIG. 3 is a schematic block diagram of an on-line monitoring device for a circuit breaker according to an exemplary embodiment of the present disclosure.

Detailed ways

In order to further illustrate the principle and structure of the present disclosure, the preferred embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings.

As shown in FIG. 1 , the present disclosure provides a switch cabinet, which includes a cabinet body 10 and an on-line monitoring device for circuit breakers disposed in the cabinet body. The cabinet body 10 includes a circuit breaker room 101 and a low-voltage room 102 . The circuit breaker 20 and the electrical anti-jump box 40 are arranged in the circuit breaker room 101 . The current acquisition unit is arranged in the electrical anti-jump box 40 , and the wireless receiving module 30 is arranged in the low voltage chamber 102 .

Since the current acquisition unit for acquiring the current signal of the circuit breaker is arranged in the electrical anti-jump box 40 , the current acquisition unit utilizes the current of the opening coil and the current of the closing coil of the circuit breaker 20 originally connected inside the electrical anti-jump box 40 . and energy storage motor current, and collect the corresponding current signal. Under the condition that the original anti-jump function of the electrical anti-jump box 40 is retained, the current signal connected to it can be reused, and it is not necessary to re-modify the pull wire to monitor the current signal, which saves manpower and material resources for modification.

In one embodiment, the present disclosure provides an online monitoring device for a circuit breaker, the online monitoring device includes a circuit breaker 20 and a collection module. The acquisition module can be an integrated module with a housing.

The acquisition module includes a current acquisition unit. As shown in FIG. 2 and FIG. 3 , the current acquisition unit is integrated on the anti-jump control board 41 inside the electrical anti-jump box 40 . The current acquisition unit may include an opening coil current sensor 42, a closing coil current sensor 43 and an energy storage motor current sensor 44, which are used to collect the opening coil current, closing coil current and energy storage motor current, respectively. The opening coil current sensor 42 , the closing coil current sensor 43 and the energy storage motor current sensor 44 may be on-board Hall current sensors, which are all installed on the anti-jump control board 41 . The anti-jump control board 41 is provided with a plurality of external interfaces 411, as shown in FIG. 2, for example, external interfaces 1-18. These external interfaces can be integrated on the same interface module. The opening coil current, closing coil current and energy storage motor current of the circuit breaker can be conducted to the corresponding external interfaces, for example, to the external interfaces 8 , 10 , and 14 through conductors such as wires. Each on-board Hall current sensor of the current acquisition unit is respectively connected with an external interface connected to the current of the opening coil, the current of the closing coil and the current of the energy storage motor. For example, the current acquisition unit includes three on-board Hall current sensors, one of which is connected to the external interface 8 connected to the current of the opening coil, the other is connected to the external interface 10 connected to the current of the closing coil, and the last one is connected to the external interface 8 connected to the current of the closing coil. The external interface 14 for storing the motor current is connected.

In order to realize the anti-jump function of the electrical anti-jump box 40, the current of the opening coil, the current of the closing coil and the current of the energy storage motor have been introduced. Therefore, a current acquisition unit is added on the anti-jump control board 41 of the electrical anti-jump box 40. , the data of the opening coil current, closing coil current and energy storage motor current of the circuit breaker can be directly collected. There is no need to make major modifications to the original equipment, which saves a lot of modification costs and reduces the power outage time caused by the modification.

Therefore, in this embodiment, the current acquisition unit is installed on the anti-jump control board, and the circuit is opened by using the current of the opening coil, the current of the closing coil and the current of the energy storage motor that were originally connected to the anti-jump control board to realize the anti-jump function. In this way, under the condition of not changing the original mechanical structure and electrical secondary wiring structure of the circuit breaker, and maintaining the original electrical anti-jump function, the collection of relevant state data of the circuit breaker can be realized. It provides data support for the operation status monitoring and diagnostic analysis of circuit breakers. In addition, the structural modification of the present disclosure is small, which can realize rapid modification and save a lot of manpower, material resources and other modification costs.

The current acquisition module further includes a plurality of expansion interfaces 412 arranged on the anti-jump control board 41, for example, expansion interfaces 19-26. These expansion interfaces 19-26 can be integrated on the same expansion interface module.

The chassis motor current at the bottom of the circuit breaker is connected to the anti-jump control board through one of the expansion interfaces 412, for example, through the expansion interfaces 21-22. The current acquisition unit further includes a chassis motor current sensor 45 arranged on the anti-jump control board 41 , and the chassis motor current sensor 45 is electrically connected to the extension interface 412 for accessing the chassis motor current to collect the chassis motor current. The chassis motor current sensor 45 may be an on-board Hall current sensor.

In this embodiment, the acquisition unit includes 4 on-board Hall current sensors, and the 4 on-board Hall current sensors are respectively connected to the three external interfaces connected to the current of the opening coil, the current of the closing coil and the current of the energy-storing motor. It is connected to an extension interface that enters the motor current of the chassis car to collect the current of the opening coil, the current of the closing coil, the current of the energy storage motor and the current of the chassis car motor. The Hall current sensor is small in size and high in sensitivity. It does not interfere with the circuit principle and circuit of the original electrical anti-jump control box, and does not affect its electrical anti-jump function.

In addition, in the description of the present disclosure, it should be understood that the term "a" is a general reference, which may refer to one or a group, a row, etc., and its actual meaning should be determined in conjunction with the specific artistic conception.

Another expansion interface among the plurality of expansion interfaces 412 is electrically connected to the angular displacement sensor 46 for detecting the rotation angle of the main shaft of the circuit breaker through a conductive wire. For example, the expansion interfaces 23 - 25 are electrically connected to the angular displacement sensor 46 . An angular displacement sensor 46 is installed close to the main shaft.

The acquisition module further includes an analog-to-digital conversion unit electrically connected to the current acquisition unit and a processor electrically connected to the analog-to-digital conversion unit. That is, the on-board Hall current sensor is electrically connected with the analog-to-digital conversion unit to convert the collected analog current signal into a digital signal. The extension interface electrically connected with the angular displacement sensor is electrically connected with the analog-to-digital conversion unit, so as to convert the analog voltage signal collected by the angular displacement sensor into a digital signal. The analog-to-digital converted data is input to the processor, and the processor processes the data. For example, the processor records the current-time current waveform of the closing and opening coils in the whole process of closing and opening through the wave recording function, and analyzes the feature point extraction algorithm for the current waveform to extract, for example, the maximum current of the closing coil. , the minimum current of the closing coil, the energized time of the closing coil, the average operating current, the maximum operating current, the maximum energy storage motor current, the time when the chassis car is shaken in and out, and the maximum chassis car motor current and other eigenvalues, and the extracted eigenvalues store. For another example, the processor records the spindle angle waveform of the entire closing process through the wave recording function, and converts the angle waveform into a stroke waveform through the angle-stroke conversion model; The maximum stroke, minimum stroke, closing speed and other eigenvalues are used for mechanical characteristic analysis, and the extracted eigenvalues are stored.

Further, the online monitoring device further includes a wireless receiving module 30, and the acquisition module further includes a first wireless communication unit electrically connected to the processor. The current waveform, the stroke waveform and the characteristic value stored in the acquisition module are sent to the wireless receiving module 30 through the first wireless communication unit. The wireless receiving module 30 is arranged in the low-voltage room, so there is no need to modify the secondary wiring.

The wireless receiving module 30 includes a circuit board, a processing unit disposed on the circuit board, and a second wireless communication unit. The second wireless communication unit communicates wirelessly with the first wireless communication unit to receive the current waveform, the stroke waveform data and the characteristic value data of the current acquisition unit. The processing unit saves the waveform data in the standard COMTRADE format, saves the eigenvalue data as a report, and uploads it to the background diagnosis system through the network port of the wireless receiving module 30 according to the IEC103 protocol. Based on these data, the background diagnostic system performs monitoring, fault warning and life analysis of circuit breakers. Signals can be transmitted between the wireless receiving module 30 and the background diagnostic system through wired communication. The wireless receiving module 30 is connected with the acquisition module for wireless communication, and does not need an air plug, which ensures primary and secondary isolation and improves safety performance.

The on-line monitoring device also includes a plurality of circuit breaker contacts, contact arms, busbar laps, and cable laps for monitoring the circuit breaker contacts, contact arms, busbar laps, and cable laps, respectively. The wireless temperature sensor 61, the wireless receiving module 30 is connected with the wireless temperature sensors 61 for wireless communication, so as to receive the temperature data collected by each wireless temperature sensor 61, so as to monitor the temperature rise of the main circuit. Communication between the wireless receiving module 30 and the wireless temperature sensors 61 can be performed by means of communication methods such as Zigee, 2.4G communication frequency band, and the like.

The online monitoring device further includes an expansion module 50 disposed in the low-voltage room, and the expansion module 50 is serially connected to the wireless receiving module 30, for example, serially connected through SPI. The expansion module 50 includes an expansion circuit board, a processor disposed on the expansion circuit board, and an analog-to-digital conversion unit electrically connected to the processor.

The expansion module 50 has multiple interfaces, and the three-phase main circuit current and the grounding switch motor current are connected to the expansion module 50 through corresponding interfaces.

The online monitoring device further includes a main circuit current sensor 51 for monitoring the three-phase main circuit current of the circuit breaker and a grounding switch current sensor 52 for monitoring the motor current of the grounding switch. The main circuit current sensor 51 is connected to the interface for accessing the three-phase main circuit current, and the grounding switch current sensor 52 is connected to the interface for accessing the motor current of the grounding switch. The expansion module 50 is an integrated module with a housing. The main circuit current sensor and the grounding switch current sensor can be located outside the expansion module 50 and are connected to the interface of the expansion module through connecting wires. Of course, the main circuit current sensor and the grounding switch current sensor It can also be located inside the expansion module 50 .

The expansion module 50 also includes a binary input detection unit and a binary input detection interface for detecting the opening and closing times of the circuit breaker. The binary input detection interface is electrically connected to the secondary circuit of the switch cabinet through wires to obtain switching signals.

The binary input detection unit includes a voltage divider circuit and a binary input sensor. The binary input sensor is arranged inside the expansion module 50 , for example, on an expansion circuit board of the expansion module 50 . The expansion module 50 transmits the binary input detected by the binary input sensor to the wireless receiving module 30 through serial communication.

The main circuit current sensor and the grounding switch current sensor are open-type Hall current sensors. The open-type sensor is used to connect the corresponding current to collect the three-phase main circuit current and the grounding switch motor current without modifying the secondary wiring. The binary input sensor is an optical coupling sensor. The binary input sensor is arranged on the expansion circuit board to realize photoelectric isolation.

The wireless receiving module 30 processes and analyzes the data collected by the main circuit current sensor and the grounding switch current sensor, produces a current waveform diagram, and extracts the breaking current of the circuit breaker, arcing time, electrical life, grounding switch motor charging time, maximum Characteristic values such as grounding switch motor current, and upload the processed waveform data and characteristic value data to the background diagnosis system.

The wireless receiving module 30 can be used to analyze the switch quantity alarm signals such as the circuit breaker closing and opening circuit disconnection by receiving the switch quantity information collected by the optical coupling sensor.

The above are only preferred feasible embodiments of the present disclosure, and do not limit the protection scope of the present disclosure. All equivalent structural changes made by using the contents of the description and drawings of the present disclosure are included in the protection scope of the present disclosure.

Claims (12)

1. an on-line monitoring device of a circuit breaker, is characterized in that, comprises: circuit breakers; and The current acquisition unit is integrated on the anti-jump control board inside the electrical anti-jump box, the anti-jump control board is provided with a plurality of external interfaces, the current of the opening coil, the current of the closing coil and the energy storage of the circuit breaker The motor current is connected to the anti-jump control board through the external interface, and the current acquisition unit is electrically connected to the external interface connected to the opening coil current, the closing coil current and the energy storage motor current to collect the circuit breaker The opening coil current, closing coil current and energy storage motor current. 2 . The on-line monitoring device of the circuit breaker according to claim 1 , wherein the on-line monitoring device further comprises an acquisition module arranged on the anti-jump control board, and the acquisition module comprises the current acquisition unit. 3 . , an analog-to-digital conversion unit electrically connected to the current acquisition unit, a processor electrically connected to the analog-to-digital conversion unit, and a first wireless communication unit electrically connected to the processor; The acquisition module further includes a plurality of expansion interfaces arranged on the anti-jump control board, and the current of the chassis vehicle motor of the circuit breaker is connected to the anti-jump control board through one of the expansion interfaces, and the current is collected. The unit is electrically connected to the extension interface for accessing the motor current of the chassis vehicle, so as to collect the motor current of the chassis vehicle. 3. The on-line monitoring device of a circuit breaker according to claim 2, wherein the current acquisition unit comprises a plurality of on-board Hall current sensors, each on-board Hall current sensor is connected to the current of the access opening coil , one of the external interfaces or one of the expansion interfaces of the closing coil current, energy storage motor current and chassis motor current to collect the opening coil current, closing coil current, energy storage motor current and chassis vehicle current. motor current. 4 . The online monitoring device of the circuit breaker according to claim 2 , wherein another expansion interface among the plurality of expansion interfaces is electrically connected to an angular displacement sensor for detecting the rotation angle of the main shaft of the circuit breaker; 5 . The expansion interface electrically connected with the angular displacement sensor is electrically connected with the analog-to-digital conversion unit, so as to convert the analog voltage signal collected by the angular displacement sensor into a digital signal. 5 . The online monitoring device of a circuit breaker according to claim 4 , wherein a plurality of the external interfaces are integrated on the same external interface module, and a plurality of expansion interfaces are integrated on the same expansion interface module. 6 . 6. The on-line monitoring device of the circuit breaker according to claim 1, characterized in that, The online monitoring device further includes a wireless receiving module; The on-line monitoring device further includes an acquisition module, which includes the current acquisition unit, an analog-to-digital conversion unit electrically connected to the current acquisition unit, a processor electrically connected to the analog-to-digital conversion unit, and a processor electrically connected to the current acquisition unit. The first wireless communication unit electrically connected to the processor, the processor processes the digital-to-analog converted current data, generates a current-time current waveform diagram, extracts characteristic values from the current waveform diagram, and converts the current waveform The map and the extracted feature values are sent to the wireless receiving module through the first wireless communication unit. 7 . The online monitoring device for a circuit breaker according to claim 6 , wherein the wireless receiving module comprises a circuit board, a processing unit arranged on the circuit board, and a second wireless communication unit, and the second wireless communication unit The wireless communication unit communicates wirelessly with the first wireless communication unit to receive the current-time current waveform data and eigenvalue data of the current acquisition unit, and the processing unit saves the waveform data in a standard COMTRADE format, and the eigenvalue The data is saved as a report and uploaded to the background diagnosis system through the network port of the wireless receiving module according to the IEC103 protocol. 8. The on-line monitoring device for a circuit breaker according to claim 7, wherein the on-line monitoring device further comprises a plurality of monitoring devices for monitoring the circuit breaker contact, contact arm, busbar overlap, and cable overlap. A wireless temperature sensor, the wireless receiving module is connected with each of the wireless temperature sensors for wireless communication to receive temperature data collected by each of the wireless temperature sensors. 9 . The on-line monitoring device for a circuit breaker according to claim 8 , wherein the on-line monitoring device further comprises an expansion module, and the expansion module is serially connected to the wireless receiving module; 10 . The expansion module includes an expansion circuit board, a processor and an analog-to-digital conversion unit arranged on the expansion circuit board; The expansion module has a plurality of interfaces, and the three-phase main circuit current and the grounding switch motor current are connected to the expansion module through the corresponding interfaces; The online monitoring device further includes a main circuit current sensor for monitoring the three-phase main circuit current of the circuit breaker and an earthing switch current sensor for monitoring the motor current of the earthing switch, the main circuit current sensor being connected to the three-phase main circuit. The current interface is connected, the grounding switch current sensor is connected to the interface for accessing the motor current of the grounding switch, and the main loop current sensor and the grounding switch current sensor are located inside or outside the expansion module. 10. The on-line monitoring device of a circuit breaker according to claim 9, characterized in that: The expansion module further includes a binary input detection unit and a binary input detection interface for detecting the opening and closing times of the circuit breaker, and the binary input detection interface is electrically connected to the secondary circuit of the switch cabinet through a wire to obtain a switching signal; The binary input detection unit is arranged inside the expansion module, the binary input detection unit includes a voltage divider circuit and a binary input sensor, and the expansion module detects the binary input sensor through serial communication. The binary input is transmitted to the wireless receiving module. 11 . The online monitoring device of a circuit breaker according to claim 10 , wherein the main circuit current sensor and the grounding switch current sensor are open-type Hall current sensors, and the binary input sensor is an optical coupling sensor. 12 . 12. A switchgear, characterized in that, comprising: Cabinet, including circuit breaker room and low voltage room; an electrical anti-jump box provided in the circuit breaker compartment, and The online monitoring device for a circuit breaker according to any one of claims 1 to 11, wherein the circuit breaker of the online monitoring device is arranged in the circuit breaker room, and the current acquisition unit of the online monitoring device is arranged in the electrical protection device. In the jump box, the wireless receiving module of the online monitoring device is arranged in the low-voltage room.

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