CN118554271A - Fixed low-voltage distribution switch cabinet capable of wiring rapidly - Google Patents

Abstract

The present invention discloses a fixed low-voltage power distribution switch cabinet with rapid wiring; the present invention relates to the technical field of complete switchgear for power distribution; according to actual needs, the equipment can be configured as a distribution circuit scheme or a motor protection circuit scheme. The distribution circuit scheme is mainly composed of a knife-type isolator 1, a primary busbar 3, a measurement and protection module 4 and a molded case circuit breaker 5 in series. The motor protection circuit scheme adds an AC contactor 9 and a corresponding measurement and protection module 8 on the basis of the distribution circuit. Through highly integrated and modular design, the present invention significantly simplifies the wiring process of the switchgear. The connection points of each module are reduced, and the wiring is more intuitive and concise. This not only reduces the error rate during the installation process, but also greatly improves the installation efficiency. Due to the reduction of complex secondary circuits and connection points, the overall reliability of the equipment is significantly improved.

Description

A fast wiring fixed low-voltage power distribution switch cabinet

Technical Field

The present invention relates to the technical field of complete sets of power distribution switchgear, in particular to a power distribution circuit scheme and a motor protection circuit scheme of a switch cabinet, and in particular to a fixed low-voltage power distribution switch cabinet with rapid wiring.

Background Art

Fixed low-voltage power distribution switchgear, as a key component with extremely flexible design and wide application in the distribution network, has become an indispensable terminal power equipment in the distribution network system, industrial and residential power consumption fields. The configuration and wiring design of its primary and secondary circuits are crucial to ensure the stable operation of the power distribution system of the power grid, and also have a profound impact on the product design and construction costs of equipment manufacturers.

In traditional fixed low-voltage switchgear, two circuit designs are common. The first is the conventional power distribution circuit, whose primary part is mainly composed of knife-type isolators, molded case circuit breakers and low-voltage transformers; while the secondary part includes opening and closing indicators and power meters. This design requires at least an indicator light circuit, a voltage sampling circuit and a current sampling circuit to be arranged between the primary and secondary, and the wiring is relatively complicated.

Another design is the motor protection circuit, whose primary part consists of a knife-type isolator, a molded case circuit breaker, an AC contactor, and a motor protector acquisition unit or a thermal relay; the secondary part includes a start indicator light, a stop indicator light, a start and stop button, and a motor protection acquisition and display unit. Therefore, at least an indicator light circuit, a contactor pull-in (start) and self-holding control circuit, and a current/voltage acquisition lock and protection circuit are required between the primary and secondary of this circuit.

In addition, depending on the power (capacity) of the equipment, each switchgear may contain 1 to N (N≤10) such circuits. Since the secondary circuit is more complex than the primary circuit, the secondary circuit inside the traditional power distribution fixed low-voltage switchgear has become the biggest challenge faced by equipment manufacturers and users in the design, construction, inspection and operation and maintenance process. This complexity not only pushes up the cost of construction materials and reduces the efficiency of manual work, but also increases the probability of failure during inspection and operation and maintenance.

To this end, the present invention provides a fast-wiring fixed low-voltage power distribution switch cabinet.

Summary of the invention

In view of this, an embodiment of the present invention hopes to provide a fixed low-voltage power distribution switch cabinet with rapid wiring.

1. Overview:

The present invention aims to solve the above-mentioned technical problems by integrating the design with the key components inside the fixed low-voltage switchgear, especially by splitting the secondary devices and integrating them with the primary devices, and replacing all the control and display devices with the graphical method of the touch screen, thereby fundamentally solving the problems of complex secondary circuit design of the switchgear, low manufacturing and operation and maintenance efficiency, and at least providing a beneficial option for this.

(II) Technical solution:

2.1 Equipment composition:

This equipment mainly consists of the following parts:

2.1.1 Knife type isolator 1:

Used to isolate power during maintenance or inspection to ensure the safety of operators.

2.1.2 Primary bus 3:

As the main current transmission path of the equipment, it is responsible for distributing electrical energy to each circuit.

2.1.3 Molded case circuit breaker 5:

Provide overload and short circuit protection to ensure that the circuit can cut off the power supply in time under abnormal circumstances.

2.1.4 Measurement protection module 4/8:

It integrates measurement and protection functions to monitor the electrical parameters of the circuit in real time and trigger protection actions in abnormal situations.

2.1.5 AC contactor 9 only The motor protection circuit solution includes:

Used to control the start and stop of the motor.

2.2 Circuit configuration:

According to actual needs, the equipment can be configured as a power distribution circuit solution or a motor protection circuit solution. The power distribution circuit solution is mainly composed of a knife-type isolator 1, a primary busbar 3, a measurement and protection module 4 and a molded case circuit breaker 5 in series. The motor protection circuit solution adds an AC contactor 9 and a corresponding measurement and protection module 8 on the basis of the power distribution circuit.

2.3 Intelligent display control and communication:

2.3.1 Display and control unit 6:

Installed outside the cabinet, connected to the measurement and protection module 4/8 via wireless communication. The display and control unit is equipped with a touch screen, supports a graphical operation interface, can display the electrical parameters and protection status of each circuit in real time, and provides opening and closing control functions.

2.3.2 Signal input and output module 2:

Responsible for processing external signals and exchanging data with the measurement and protection module 4/8 through the prefabricated wiring harness 7. The module can expand the number of optical coupling relays according to demand to adapt to different external signal interfaces.

2.4 Intelligent functions:

2.4.1 Electrical parameter collection and processing:

The measurement, control and protection module 4/8 has built-in current transformers and digital temperature sensors to collect the operating current and contact temperature of the molded case circuit breaker in real time, providing basic signals for power distribution measurement display and motor protection.

2.4.2 Priority display mode:

The display and control unit 6 has two priority fixed display modes, which can automatically highlight key circuits according to the ratio of collected current to rated current or fault alarm time, making it easy for operation and maintenance personnel to quickly locate problems.

(III) Principles of implementation of the plan:

3.1 Highly integrated and modular configuration:

The key components of the knife-type isolator 1, the primary busbar 3, the molded case circuit breaker 5, the measurement and protection module 4 or 8, and the AC contactor 9 are orderly integrated inside the switchgear cabinet. At the same time, the equipment adopts modular configuration, and different numbers of modules can be flexibly configured according to different primary schemes and load quantities. Both the distribution circuit scheme and the motor protection circuit scheme are realized through modular design, so that the equipment can adapt to a variety of application scenarios.

3.2 Wireless communication and intelligent monitoring protection:

The display and control unit 6 exchanges data with the measurement and protection module 4 or 8 through wireless communication to realize remote monitoring and control functions. It gets rid of the constraints of traditional wired connections and improves data transmission efficiency and the convenience of equipment use. The measurement and control protection module has three current transformers and three digital temperature sensors built in, which can monitor the operating current and contact temperature of the molded case circuit breaker in real time. The data collected by these sensors, together with the voltage values collected by the three-phase voltage sampling line, constitute the basic signals for power distribution measurement display and motor protection. When an abnormal situation is detected, the measurement and protection module will immediately trigger the protection action, cut off the power supply, and display the fault information through the display and control unit, realizing intelligent monitoring and protection of the equipment.

3.3 Priority display mode:

The touch screen interface of the display and control unit 6 supports two priority fixed display modes: one is to automatically highlight the circuit with the highest proportion according to the proportion of the collected current to the preset rated current; the other is to highlight the alarm circuit with the latest fault according to the occurrence time of the fault alarm circuit. In addition, the display and control unit can also set soft buttons and indicator lights in a partitioned or split-screen graphical manner, replacing traditional physical buttons and indicator lights, making operation more convenient and intuitive. At the same time, the display and control unit can also cyclically display the electrical parameters such as three-phase voltage, current, power factor and protection action information of each circuit, providing comprehensive equipment operation status information for operation and maintenance personnel.

(IV) Mechanisms for resolving technical issues:

4.1 Secondary device splitting and primary device integration:

The secondary circuit design of traditional switchgear is often complicated and cumbersome. The technical solution of the present invention simplifies the wiring structure by splitting the secondary devices (such as the measurement and protection module) and tightly integrating them with the primary devices (such as the molded case circuit breaker). This integration enables each circuit to have independent measurement and protection functions, reducing the connection points and complexity of the secondary circuit.

The measurement and protection module is directly installed on the incoming line side of the molded case circuit breaker, with a one-to-one physical and electrical connection relationship, which not only improves the reliability of the equipment, but also greatly simplifies the manufacturing and installation process.

4.2 Use touch screen graphics to replace traditional control and display devices:

Traditional switchgear usually uses a large number of physical buttons, indicators and meters to display the status of the equipment and control its operation. This approach not only takes up space, but is also relatively complicated to operate and maintain.

The technical solution of the present invention adopts a touch screen as the main interface for human-computer interaction, and displays the status and control options of the equipment in a graphical manner. The operation and maintenance personnel can intuitively view the electrical parameters, protection status and fault information of each circuit through the touch screen, and can also perform operations such as opening and closing the switch through the touch screen. The use of the touch screen greatly simplifies the operation interface of the equipment and improves the operation and maintenance efficiency. The operation and maintenance personnel do not need to be familiar with a large number of physical buttons and indicator lights, and can complete the monitoring and control of the equipment through simple touch operations.

4.3 Improve manufacturing and operation efficiency:

The manufacturing process of the equipment has been simplified due to the separation of secondary devices and their integration with primary devices, as well as the application of touch screen graphical interfaces. Manufacturers can assemble and debug equipment faster, improving production efficiency. For operation and maintenance personnel, the simple and intuitive touch screen interface reduces the possibility of misoperation, while providing richer equipment status information, making troubleshooting and maintenance faster and more accurate.

Compared with the prior art, the present invention has the following beneficial effects:

1. Simplify wiring and improve reliability: The present invention uses highly integrated and modular design, and the technical solution significantly simplifies the wiring process of the switchgear. The number of connection points of each module is reduced, and the wiring is more intuitive and concise. This not only reduces the error rate during installation, but also greatly improves installation efficiency. Due to the reduction of complex secondary lines and connection points, the overall reliability of the equipment has been significantly improved. At the same time, the built-in sensors of the measurement and protection module can monitor electrical parameters in real time. Once an abnormality is found, the protection measures will be triggered immediately to ensure the safety of equipment and personnel.

2. Intelligent monitoring and fault diagnosis: The technical solution of the present invention incorporates intelligent monitoring functions, and the operating status, electrical parameters and fault information of the equipment can be viewed in real time through the display and control unit. This intelligent management method helps operation and maintenance personnel to quickly locate and solve problems, reduce downtime and improve production efficiency.

3. Improve operation and maintenance efficiency: The present invention uses a touch screen as a human-machine interaction interface, making the operation of the device more intuitive and convenient. The operation and maintenance personnel do not need to tediously search and read a large number of physical buttons and indicator lights, and can quickly complete the monitoring and control of the equipment through the touch screen. In addition, the remote monitoring function also allows the operation and maintenance personnel to monitor and maintain the equipment at any location, further improving the operation and maintenance efficiency.

4. Flexibility and low cost: The modular design of the present invention makes the equipment highly flexible and scalable. According to different application requirements, the number of modules can be easily increased or decreased to meet the requirements of power systems of different scales and complexities. The simplified wiring, installation and operation and maintenance process means reduced investment in manpower, material resources and time, thereby reducing overall costs. In addition, the highly integrated design also reduces the use of materials, further saving costs.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

FIG1 is a schematic diagram of the layout of components and quick wiring connections of a power distribution circuit according to the present invention;

FIG2 is a schematic diagram of the prefabricated wiring of the measurement, control and protection module 4 of the present invention;

FIG3 is a schematic diagram of the layout of components and quick wiring connections of a motor protection circuit according to the present invention;

FIG4 is a schematic diagram of the prefabricated wiring of the measurement, control and protection module 8 of the present invention;

DETAILED DESCRIPTION

In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below;

It should be noted that the term "N" in this specification refers to a plurality of quantitative features.

It should be noted that the various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part description.

Example 1: Please refer to Figures 1 to 4:

The present embodiment discloses a switch cabinet for a power distribution circuit solution, including a knife-type isolator, a primary bus, a molded case circuit breaker, a measurement and protection module, and an AC contactor arranged in the cabinet; a display and control unit is provided outside the cabinet and is electrically connected to multiple measurement and protection modules in the cabinet, thereby forming a one-to-many master-slave data interaction with the devices in the cabinet.

In this embodiment, the core components include:

(1) Knife-type isolator 1: As the primary protection element of the power distribution circuit, the knife-type isolator 1 plays a key role in ensuring the safety of maintenance personnel. It can quickly cut off the power supply when maintenance personnel need it, providing a safe working environment for maintenance personnel.

(2) Primary bus 3: The primary bus 3 is the core conductive part in the distribution circuit and is responsible for transmitting electrical energy from the power source to each branch circuit.

(3) Measurement and protection modules: These modules are the "intelligent brain" of the power distribution circuit. They have built-in advanced sensors and microprocessors that can monitor the electrical parameters of the circuit in real time, such as voltage and current. Once an abnormal situation is found, such as overload or short circuit, the measurement and protection module will immediately trigger protection measures to cut off the power supply to the faulty part, thereby preventing the fault from expanding. In practice, corresponding circuit sensor devices can be selected.

(4) Molded case circuit breaker 5: As an important protection device in the power distribution circuit, the molded case circuit breaker 5 can quickly cut off the circuit when the current exceeds the set value to prevent the equipment and lines from being damaged due to overload. Its sturdy shell and excellent performance enable it to work reliably in various harsh environments.

In this embodiment, the electrical connection method is that the following elements are connected in series in sequence:

The three A/B/C incoming voltage sampling prefabricated wires and the A phase outgoing voltage sampling prefabricated wire are directly electrically connected to the molded case circuit breaker 5. This connection method not only simplifies the wiring process, but also improves the reliability and safety of the electrical connection. Through these prefabricated wires, the measurement and protection module can collect the voltage data of the circuit in real time, providing an accurate basis for fault diagnosis and protection action.

In this embodiment, regarding the efficient signal transmission and processing system: a group of signal input and output modules are installed inside the switch cabinet, and the modules are connected to all measurement and protection modules in a daisy chain manner through prefabricated wires. This connection method enables signals to be efficiently transmitted between modules, realizing one-to-many data interaction between the master device and the slave devices. In addition, the cabinet is also equipped with a signal input and output expansion unit, which is provided with multiple optically coupled multi-channel relays for receiving and sending external input and output signals respectively. This design enables the switch cabinet to seamlessly connect with external devices and realizes the intelligent management of the power system.

In this embodiment, regarding the user-friendly operation and display interface: in order to facilitate user operation and monitoring of the operating status of the power distribution circuit, a display and control unit is provided on the outside of the switch cabinet. The display and control unit is provided with a touch screen interface, and the user can intuitively view the various electrical parameters and protection action information of the circuit. At the same time, the touch screen also supports the setting of soft buttons and indicator lights in partitions or split screens, making the operation more convenient. In addition, the display and control unit can also cyclically display the key information such as three-phase voltage, three-phase current, power factor, power, frequency, etc. of multiple circuits of the power distribution circuit scheme or the motor protection circuit scheme, helping users to fully understand the operating status of the power system.

Embodiment 2: Please refer to Figures 1 to 4: This embodiment discloses a switch cabinet for a motor protection circuit solution, including a knife-type isolator, a primary bus, a molded case circuit breaker, a measurement and protection module and an AC contactor arranged in the cabinet; a display and control unit is provided outside the cabinet, which is electrically connected to multiple measurement and protection modules in the cabinet, thereby forming a one-to-many master-slave data interaction with the devices in the cabinet.

In this embodiment, the core components and their connection methods are as follows:

(1) Knife-type isolator 1: As the main switch of the motor protection circuit, the knife-type isolator can quickly cut off the power supply when necessary to ensure the safety of maintenance and operating personnel.

(2) Primary bus 3: It plays the role of distributing electric energy in the circuit. It stably transmits electric energy from the power source to each branch circuit, providing a continuous and stable power supply for the motor.

(3) Measurement and protection modules: These modules are intelligent components in the motor protection circuit. They have built-in sensors and microprocessors and are responsible for real-time monitoring of the electrical parameters of the circuit. In the motor protection circuit solution, multiple measurement and protection modules are connected in series, and each module has a one-to-one physical and electrical connection relationship with a molded case circuit breaker 5. This design allows each motor branch circuit to be independently monitored and protected.

(4) Molded case circuit breaker 5: Multiple molded case circuit breakers are configured in the circuit, and each circuit breaker corresponds to a measurement and protection module. When the measurement and protection module detects abnormal electrical parameters, it will trigger the corresponding molded case circuit breaker to trip, thereby cutting off the fault circuit and protecting the motor from damage.

(5) AC contactor: A key component that controls the start, stop, and forward and reverse rotation of the motor. In the motor protection circuit solution, the AC contactor is connected to the measurement and control protection module through prefabricated wires to achieve remote control and status monitoring.

In this embodiment, the detailed functions of the measurement, control and protection module are as follows:

(1) Voltage sampling: The measurement, control and protection module collects three-phase voltage values in real time through the three incoming voltage sampling prefabricated lines A/B/C, which serves as one of the signal sources for power distribution measurement and motor protection.

(2) Current sampling and temperature monitoring: The measurement and control protection module has multiple built-in current transformers to collect current signals of each phase. At the same time, the module is also equipped with digital temperature sensors corresponding to the number of current transformers to monitor the temperature of the contacts in real time. These current and temperature data provide important basis for judging motor overload, short circuit and other faults.

(3) Protection and control signal output: When the measurement and control protection module detects an abnormality, it will send a control signal to the AC contactor through the two output prefabricated lines A1/A2 to achieve operations such as rapid shutdown or reversal of the motor. At the same time, the three status signal acquisition prefabricated lines NO/NC/COM are used to monitor the status of the AC contactor in real time to ensure the accurate execution of control instructions.

In this embodiment, regarding the intelligent management of the display and control unit:

As an external monitoring device for the motor protection circuit solution, the display and control unit has the following functions:

(1) Touch screen operation interface: The display and control unit is equipped with a touch screen, and the operation interface is intuitive and easy to use. Users can view various electrical parameters of the circuit, protection action information, and the operating status of the motor through the touch screen.

(2) Multi-circuit cyclic display: The display and control unit can cyclically display key information such as three-phase voltage, three-phase current, power factor, power, frequency, etc. of multiple circuits of the power distribution circuit scheme or motor protection circuit scheme. This helps users fully understand the operating status of the entire electrical system.

(3) Fault alarm and recording: When a fault occurs in the motor protection circuit, the display and control unit will immediately send out an alarm signal and record the fault information, providing strong support for users to quickly locate the cause of the fault and take corresponding measures.

Application example: Based on the switch cabinet disclosed in embodiments 1 and 2, this example will further disclose its actual installation method and principle details. Please refer to Figures 1 to 4:

In this embodiment, regarding the application method of the power distribution circuit solution: as shown in FIG1 , the lower end of the knife-shaped isolator 1 is electrically connected to the upper end of the primary bus 3. The primary bus 3 is set accordingly according to the number of molded case circuit breakers 5, and passes through N measurement and protection modules 4 to be electrically connected to the incoming line side of the N molded case circuit breakers 5. The outgoing line side of the molded case circuit breaker 5 is connected to N distribution loads.

Specifically, data communication and interaction include: a prefabricated wiring harness 7, including a set of 24V power lines, a set of shielded twisted pair cables and a quick-plug connector, for data communication between modules. It starts from the measurement and control protection module 4 farthest from the signal input and output module 2, and is connected to the input and output modules 2 one by one in a daisy chain manner.

The display and control unit 6 is installed on the cabinet door outside the power distribution equipment cabinet, and exchanges data with the measurement and protection module 4 through a 1-to-N wireless communication method, and is equipped with a gain antenna to enhance the signal.

Specifically, the measurement and protection functions include: a measurement and control protection module 4, which has at least three incoming voltage sampling lines A/B/C preset and is electrically connected to the incoming terminal of the molded case circuit breaker 5 for collecting three-phase voltage. The module 4 has three built-in current transformers and a digital temperature sensor for collecting operating current and contact temperature, which will serve as the basic signal source for measurement, protection and display of the distribution circuit.

Specifically, the display and control include: a display control unit 6, equipped with a touch screen, which can graphically set soft buttons and indicator lights to replace traditional opening and closing buttons and status indicator lights. The three-phase voltage, current, power factor, power, frequency, contact temperature and protection action information of each circuit can be displayed cyclically. The display control unit 6 has two priority fixed display modes: highlighting according to the current proportion or fault alarm time.

In this embodiment, regarding the application method of the motor protection circuit solution: similar to the power distribution circuit, the connection method of the knife-shaped isolator 1, the primary busbar 3, the measurement protection module 8 and the molded case circuit breaker 5 is consistent. The difference is that the outgoing line side of the molded case circuit breaker 5 is connected to the upper end of N AC contactors 9, and the lower end of the AC contactor 9 is connected to the motor load. The communication method is the same as the power distribution circuit, using a prefabricated wiring harness 7 for wired communication and a display and control unit 6 for wireless communication.

Specifically, in addition to collecting three-phase voltage, the measurement and control protection module 8 also presets prefabricated lines related to the AC contactor 9 to control the start, hold, release and status signal collection of the contactor. It also has built-in current transformers and digital temperature sensors, and the collected data is used for motor measurement and protection. The function of the display and control unit 6 is similar to that of the power distribution circuit, but it can display information specific to the motor protection circuit and control the related operations of the AC contactor 9. It also has two priority fixed display modes to quickly identify high-load or faulty circuits.

All the above embodiments only express the implementation methods of the relevant practical applications of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be based on the attached claims.

For those skilled in the art, it can be further appreciated that the units and algorithm steps of each example described in conjunction with the embodiments disclosed herein can be implemented in electronic hardware, computer software, or a combination of the two. In order to clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described in the above description according to function. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professional and technical personnel can use different methods to implement the described functions for each specific application, but such implementation should not be considered to be beyond the scope of the present invention.

Claims (10)

1. A fast-wiring fixed low-voltage power distribution switch cabinet, comprising a knife-type isolator, a primary busbar, a molded case circuit breaker, a measurement and protection module and an AC contactor arranged in the cabinet according to a power distribution circuit scheme or a motor protection circuit scheme; characterized in that: A display and control unit is provided outside the cabinet and is electrically connected to multiple measurement and protection modules inside the cabinet, thereby forming a one-to-many master-slave data interaction with the devices inside the cabinet. 2. The fixed low-voltage power distribution switch cabinet according to claim 1 is characterized in that: the power distribution circuit scheme is composed of the following elements connected in series: A knife-type isolator, a primary busbar, a plurality of the measurement and protection modules and a plurality of molded case circuit breakers. 3. The fixed low-voltage power distribution switch cabinet according to claim 2 is characterized in that: the power distribution circuit scheme also includes three preset A/B/C incoming line voltage sampling prefabricated wires and one A-phase outgoing line voltage sampling prefabricated wire, which are electrically connected to the molded case circuit breaker. 4. The fixed low-voltage power distribution switch cabinet according to claim 1 is characterized in that: the motor protection circuit scheme is composed of the following elements connected in series: Knife-type isolator, primary busbar, multiple measurement and protection modules, multiple molded case circuit breakers and multiple AC contactors. 5. The fixed low-voltage power distribution switch cabinet according to claim 4 is characterized in that: the motor protection circuit solution also includes three A/B/C incoming line voltage sampling prefabricated wires preset by the measurement and control protection module, which are electrically connected to the molded case circuit breaker; The plurality of measurement, control and protection modules are installed on the incoming line sides of the plurality of molded case circuit breakers and have a one-to-one corresponding physical and electrical connection relationship. 6. The fixed low-voltage power distribution switch cabinet according to claim 5 is characterized in that: in the motor protection circuit scheme, the measurement and control protection module is also preset with two output prefabricated wires A1/A2 and three status signal acquisition prefabricated wires NO/NC/COM that are electrically connected to the AC contactor. 7. The fixed low-voltage power distribution switch cabinet according to claim 1, 2 or 4 is characterized in that a group of signal input and output modules are also installed inside the cabinet, and are daisy-chain connected to all the measurement and protection modules through prefabricated wires. 8. The fixed low-voltage power distribution switch cabinet according to claim 7 is characterized in that it also includes a signal input and output expansion unit provided with multiple optically coupled multi-way relays and used to receive and send external input and output signals respectively, which is electrically connected to the external signal through terminals. 9. The fixed low-voltage power distribution switch cabinet according to claim 4 or 6 is characterized in that: the measurement, control and protection module is equipped with multiple current transformers and digital temperature sensors corresponding to the number; the current transformer collects current signals as one of the measurement and protection signal sources, and together with the three-phase voltage value and the three contact temperature values, serves as a signal source for power distribution measurement and motor protection. 10. The fixed low-voltage power distribution switch cabinet according to claim 1, 2, 4 or 5, characterized in that: the display and control unit is provided with a touch screen, and soft buttons and indicator lights are provided in partitions or split screens; The display and control unit cyclically displays the three-phase voltage, three-phase current, power factor, power, frequency and protection action information of multiple circuits of the power distribution circuit scheme or the motor protection circuit scheme.