Intelligent maintenance device for low-voltage ac power distribution system

Abstract

The application belongs to the technical field of automatic detection, and relates to a low-voltage alternating-current power distribution system intelligent maintenance device, which comprises: a customized compression force sensor, which is used for generating a voltage analog signal representing the compression force of a main contact and transmitting the voltage analog signal to a current transmitter; an alternating-current programmable constant-current power supply, which is used for outputting a preset current to the main contact and an internal main loop of a measured power distribution drawer; the current transmitter, which is used for collecting voltage analog signals of each main contact of the measured power distribution drawer and current analog signals flowing into the measured power distribution drawer and transmitting the voltage analog signals and the current analog signals to an analog quantity processing box; the analog quantity processing box, which is used for converting the voltage analog signals and the current analog signals into digital signals and transmitting the digital signals to an industrial personal computer through a serial port server and a switch; and the industrial personal computer, which is used for controlling the alternating-current programmable constant-current power supply to output the preset current, recording and displaying the digital signals, and recording the time of the output current of the alternating-current programmable constant-current power supply. The application has a wide application range, complete functions, high automation degree and convenient operation.

Description

Technical Field

[0001] This invention belongs to the field of automated detection technology, specifically relating to an intelligent maintenance device for low-voltage AC power distribution systems. Background Technology

[0002] The verification and maintenance of the distribution drawer in a low-voltage AC power distribution system generally includes verifying and maintaining the clamping force of the main contacts of the distribution drawer, verifying and maintaining the operating current and operating time of the thermal relay inside the distribution drawer, and verifying and maintaining the operating current and operating time of the leakage protection relay inside the distribution drawer.

[0003] Currently, the calibration and maintenance of distribution drawers in low-voltage AC power distribution systems requires personnel to equip themselves with a large number of instruments. These instruments are then connected to the drawers using wires. Personnel manually adjust the instruments according to testing procedures and manually enter the test data into tables. This process is inefficient and demands a high level of technical expertise from the personnel. Calibrating the clamping force of the main contacts of the distribution drawer requires personnel to use a handheld clamping force tester to measure multiple main contacts one by one. A typical three-phase distribution drawer requires at least six measurements. During each contact clamping force test, the tester's force point must be repeatedly aligned to avoid significant measurement errors. After measurement, data must be manually recorded, and the clamping force of each contact must be judged to be within acceptable limits. The clamping force measurement and calibration is particularly time-consuming. Furthermore, since the calibration of the thermal relays in the distribution drawers requires the application of currents of up to several hundred amps, manual calibration operations pose significant risks. With the advancement of automated testing technology, many intelligent maintenance devices for low-voltage AC power distribution systems have been developed, which have improved the automation level of power distribution drawer verification and maintenance to a certain extent. However, these devices generally have the following shortcomings: the verification and maintenance functions of the devices are incomplete, such as the lack of automatic testing and verification function for the main contact clamping force of the power distribution drawer; the degree of automation is insufficient, and human intervention is still required during the verification process, making it impossible to complete the testing and verification of the main contact clamping force of the power distribution drawer, the thermal relay, and the leakage protection relay in the same test slot. Summary of the Invention

[0004] The purpose of this invention is to provide an intelligent maintenance device for low-voltage AC power distribution systems. This device has a wide range of applications, complete functions, a high degree of automation, and is easy to operate.

[0005] Technical solution to achieve the purpose of this invention:

[0006] A smart maintenance device for a low-voltage AC power distribution system, the device comprising:

[0007] A custom clamping force sensor is used to clamp each main contact of the distribution drawer. Based on the pressure of each main contact of the clamped distribution drawer, a voltage analog signal representing the clamping force of the main contact is generated and transmitted to the current transmitter.

[0008] An AC programmable constant current power supply is used to output a preset current to the main contacts and internal main circuit of the power distribution drawer under test;

[0009] The current transmitter is used to acquire the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test, and transmit the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test to the analog quantity processing box.

[0010] The analog signal processing box is used to convert the analog voltage signals of each main contact of the power distribution drawer under test and the analog current signals of the power distribution drawer under test into digital signals, and then transmit the digital signals to the serial port server.

[0011] A serial port server is used to transmit digital signals to an industrial control all-in-one computer via a switch.

[0012] An industrial control all-in-one computer is used to control the output current of an AC programmable constant current power supply, record and display digital signals, and record the time of the AC programmable constant current power supply output current.

[0013] The AC programmable constant current power supply includes a three-phase AC power supply and a single-phase AC power supply; the three-phase AC power supply is used for thermal relay calibration with a three-phase 0-200A AC power supply; the single-phase AC power supply is used for leakage protection relays with a single-phase 0-10A AC power supply.

[0014] The device also includes a relay matrix, used to control the relays to close and open the contactor in this circuit, or to control the relays to supply and disconnect the auxiliary power supply in this circuit.

[0015] The device also includes test slots for accommodating the power distribution drawer under test, and a customized clamping force sensor is installed in the test slots; the test slots include 8E / 2 test component fixing positions, 4E test component fixing positions, 6E test component fixing positions, and 8E test component fixing positions.

[0016] The device also includes a power switch button and a power indicator light; the power switch button is used to power on and off the device; the power indicator light is used to indicate whether the device is connected to a working power source.

[0017] The device also includes a relay base and a banana plug; the relay base is used for corresponding intermediate relay verification; the banana plug is used for the interface of the leakage protection relay to the external current transformer.

[0018] The industrial control all-in-one computer includes:

[0019] The user management module is used to set and control the usage permissions of administrators and testers;

[0020] The tested component management module is used for managing drawer cabinets and intermediate relays;

[0021] The performance testing module is used to perform contact tension testing, thermal relay verification, leakage protection relay verification, and intermediate relay verification.

[0022] The data management module is used to save test data, test results and reports, view historical data, and export test data, test results and reports.

[0023] The device is used to verify the clamping force of the main contacts of the distribution drawer in a low-voltage AC power distribution system: Each main contact of the distribution drawer clamps the corresponding customized clamping force sensor of the intelligent maintenance device for the AC power distribution system. The strain gauge inside each customized pressure sensor is subjected to force, generating a corresponding voltage analog signal that is transmitted to the current transmitter. The current transmitter collects the voltage analog signal and transmits it to the analog signal processing box. The analog signal processing box processes the voltage analog signal representing the pressure and converts it into a digital signal. The analog signal processing box transmits the digital signal representing the clamping force of the main contacts to the industrial control all-in-one computer through a serial port server and switch. The industrial control all-in-one computer records and displays the pressure data and judges whether the clamping force is qualified according to the criteria.

[0024] The device is used to calibrate the thermal relay of a power distribution drawer: the industrial control computer of the power distribution drawer controls the AC programmable constant current power supply to output a preset current through a switch. This current value is the preset operating current value of the thermal relay. At this time, the main contact of the power distribution drawer is stuck in the test slot of the intelligent maintenance device for low-voltage AC power distribution system, which is a customized pressure sensor. The current output by the AC programmable constant current power supply passes through the contactor and the housing of the customized pressure sensor to the main contact and internal main circuit of the power distribution drawer under test. The industrial control computer records the time when the AC programmable constant current power supply outputs the current. At the same time, the current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to the analog signal processing box. The analog signal processing box processes the analog current signal and converts it into a digital signal. The analog signal processing box transmits the digital signal to the industrial control computer through a serial server and a switch. When the thermal relay of the power distribution drawer operates, that is, when the main circuit is disconnected, the industrial control computer detects that the current drops to zero through the current transmitter, stops the timing, and obtains the operating current and operating time of the thermal relay.

[0025] The device is used to verify the leakage current protection relay of the power distribution drawer: the industrial control computer of the power distribution drawer controls the AC programmable constant current power supply to output a preset three-phase unbalanced current through a switch. The sum of the three-phase currents is the preset operating value of the leakage current protection relay. The current passes through the housing of a customized pressure sensor and is connected to the main contacts of the power distribution drawer under test and the internal leakage current protection relay. The software of the industrial control computer records the time of the AC programmable constant current power supply outputting the current. At the same time, the current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to the analog quantity processing box. The analog quantity processing box converts the analog current signal into a digital signal and transmits it to the serial port server. The serial port server then transmits the digital signal to the industrial control computer through the switch. When the leakage current protection relay of the power distribution drawer operates, the industrial control computer detects that the current drops to zero through the current transmitter and stops timing, thus obtaining the operating current and operating time of the leakage current protection relay.

[0026] The beneficial technical effects of this invention are as follows:

[0027] 1. The present invention provides an intelligent maintenance device for a low-voltage AC power distribution system, which can automatically complete the verification of thermal relays, leakage protection relays, and main contact clamping force of the power distribution drawer.

[0028] 2. The intelligent maintenance device for low-voltage AC power distribution system provided by this invention completes the entire verification process in one test slot, eliminating the need to move the drawer being verified multiple times. This is convenient and fast, and it automatically generates a verification report and stores the verification data in a database for easy data statistical analysis.

[0029] 3. The industrial control integrated computer detection software in the intelligent maintenance device for low-voltage AC power distribution system provided by this invention has a user-friendly interface, is simple to operate, and is easy to use. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of an intelligent maintenance device for a low-voltage AC power distribution system provided by the present invention;

[0031] Figure 2 This is a block diagram of an intelligent maintenance device for a low-voltage AC power distribution system provided by the present invention;

[0032] Figure 3 The present invention provides a schematic diagram of the main contact clamping force verification principle of a low-voltage AC power distribution system intelligent maintenance device for power distribution drawers;

[0033] Figure 4 This invention provides a schematic diagram of the thermal relay verification principle for a low-voltage AC power distribution system intelligent maintenance device used in a power distribution drawer.

[0034] Figure 5The present invention provides a schematic diagram of the verification principle of a leakage protection relay for a distribution drawer in an intelligent maintenance device for a low-voltage AC power distribution system.

[0035] Figure 6 This is a block diagram of the integrated industrial control unit in an intelligent maintenance device for a low-voltage AC power distribution system provided by the present invention.

[0036] In the diagram: 1. Touch display; 2. Power switch button; 3. Power indicator light; 4. Relay base; 5. Banana head; 6. 8E / 2 Test Device mounting position; 7. 4E Test Device mounting position; 8. 6E Test Device mounting position; 9. 8E Test Device mounting position; 10. Single-phase AC power supply; 11. Three-phase AC power supply. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0038] The present invention provides an intelligent maintenance device for a low-voltage AC power distribution system, comprising: a customized clamping force sensor, an AC programmable constant current power supply, a current transmitter, an analog signal processing box, a serial port server, a switch, and an industrial control all-in-one computer.

[0039] A custom clamping force sensor is used to clamp each main contact of the distribution drawer. Based on the pressure of each main contact of the clamped distribution drawer, a voltage analog signal representing the clamping force of the main contact is generated and transmitted to the current transmitter.

[0040] An AC programmable constant current power supply is used to output a preset current to the main contacts and internal main circuit of the power distribution drawer under test;

[0041] The current transmitter is used to acquire the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test, and transmit the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test to the analog quantity processing box.

[0042] The analog signal processing box is used to convert the analog voltage signals of each main contact of the power distribution drawer under test and the analog current signals of the power distribution drawer under test into digital signals, and then transmit the digital signals to the serial port server.

[0043] A serial port server is used to transmit digital signals to an industrial control all-in-one computer via a switch.

[0044] An industrial control all-in-one computer is used to control the output current of an AC programmable constant current power supply, record and display digital signals, and record the time of the AC programmable constant current power supply output current.

[0045] The AC programmable constant current power supply includes a three-phase AC power supply 11 and a single-phase AC power supply 10; the three-phase AC power supply 11 is a three-phase 0-200A AC power supply used for thermal relay calibration; the single-phase AC power supply 10 is a single-phase 0-10A AC power supply used for leakage protection relays, such as... Figure 1 As shown.

[0046] The device of the present invention also includes a relay matrix, which is used to control the relays to complete the closing and opening of the contactor in this circuit, or to control the relays to complete the supply and disconnection of the auxiliary power supply in this circuit.

[0047] like Figure 1 As shown, the device of the present invention includes test slots for accommodating the electrical distribution drawer under test, and a customized clamping force sensor is installed in the test slot. The test slots include an 8E / 2 test piece fixing position 6, a 4E test piece fixing position 7, a 6E test piece fixing position 8, and an 8E test piece fixing position 9. The 8E / 2 test piece fixing position 6 is used to fix the 8E / 2 test piece for testing; the 4E test piece fixing position 7 is used to fix the 4E test piece for testing; the 6E test piece fixing position 8 is used to fix the 6E test piece for testing; and the 8E test piece fixing position 9 is used to fix the 8E test piece for testing.

[0048] like Figure 1 As shown, the device of the present invention also includes a power switch button 2 and a power indicator light 3; the power switch button 2 is used to power on and power off the device; the power indicator light 3 is used to indicate whether the device is connected to a working power source.

[0049] like Figure 1 As shown, the device of the present invention also includes a relay base 4 and a banana plug 5; the relay base 4 is used for corresponding intermediate relay verification; the banana plug 5 is used for the interface of the leakage protection relay to the external current transformer.

[0050] like Figure 1 As shown, the industrial control all-in-one computer in the device of the present invention is a touch display 1.

[0051] In one specific embodiment, the present invention provides an intelligent maintenance device for a low-voltage AC power distribution system, comprising: an industrial control integrated computer, two analog signal acquisition modules, an AC programmable constant current power supply, three contactors, three current transmitters, 18 customized pressure sensors, three AC contactors, a power relay, a DC power supply, a serial port server, a switch, and a cabinet, such as... Figure 2 As shown.

[0052] The present invention provides an intelligent maintenance device for low-voltage AC power distribution systems. During maintenance, the power distribution drawer to be checked is inserted into a test slot of the intelligent maintenance device. The main contacts of the drawer engage a customized clamping force sensor installed in the test slot. The calibration process can then be initiated automatically, proceeding item by item, via an industrial control computer.

[0053] The present invention provides an intelligent maintenance device for low-voltage AC power distribution systems, which is used to verify the clamping force of the main contacts of the distribution drawer in a low-voltage AC power distribution system. Each main contact of the distribution drawer clamps the corresponding customized clamping force sensor of the intelligent maintenance device for the AC power distribution system. The strain gauge inside each customized pressure sensor is subjected to force, generating a corresponding voltage analog signal that is transmitted to a current transmitter. The current transmitter collects the voltage analog signal and transmits it to an analog signal processing box. The analog signal processing box processes the voltage analog signal representing the pressure and converts it into a digital signal. The analog signal processing box transmits the digital signal representing the clamping force of the main contacts to an industrial control all-in-one computer through a serial port server and a switch. The industrial control all-in-one computer records and displays the pressure data and judges whether the clamping force is qualified according to the criteria.

[0054] like Figure 3 As shown, the test principle and process for verifying the clamping force of the main contacts of the distribution drawer using the intelligent maintenance device for low-voltage AC power distribution systems provided by this invention are as follows:

[0055] Step 1: Insert the drawer into the test slot;

[0056] Step 2: Use the industrial control all-in-one computer to preset parameters, including setting or selecting the test drawer type, and start the test;

[0057] Step 3: The industrial control all-in-one computer sends a read command through the LAN port according to the preset parameters, and the transmitter collects the voltage signal generated by the customized pressure sensor at this time;

[0058] Step 4: The industrial control all-in-one computer converts the voltage signal data collected by the transmitter into a digital signal corresponding to the actual contact tension through the analog signal processing box. The analog signal processing box transmits the digital signal to the industrial control all-in-one computer through the serial port server and switch.

[0059] Step 5: The industrial control all-in-one computer displays the test force value and records it in the test report;

[0060] Step 6: The test is complete. Pull the drawer out of the test slot or continue with other test items.

[0061] The present invention provides an intelligent maintenance device for low-voltage AC power distribution systems, used for calibrating the thermal relay of a power distribution drawer. The industrial control computer of the power distribution drawer controls an AC programmable constant current power supply via a switch to output a preset current. This current value is the preset operating current value of the thermal relay. At this time, the main contacts of the power distribution drawer are engaged with a custom pressure sensor inside the test slot of the intelligent maintenance device for low-voltage AC power distribution systems. The current output by the AC programmable constant current power supply passes through a contactor and the housing of the custom pressure sensor to the main contacts and internal main circuit of the power distribution drawer under test. The industrial control computer records the time of the AC programmable constant current power supply outputting the current. Simultaneously, a current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to an analog signal processing box. The analog signal processing box processes the analog current signal and converts it into a digital signal. The analog signal processing box transmits the digital signal to the industrial control computer via a serial server and a switch. When the thermal relay of the power distribution drawer activates, i.e., disconnects the main circuit, the industrial control computer detects that the current drops to zero via the current transmitter and stops timing, thus obtaining the operating current and operating time of the thermal relay.

[0062] like Figure 4 As shown, the test principle and process for verifying the thermal relay of the distribution drawer using the intelligent maintenance device for low-voltage AC power distribution system provided by this invention are as follows:

[0063] Step 1: Insert the drawer into the test slot;

[0064] Step 2: Use the industrial control all-in-one computer to preset the parameters, including setting or selecting the test drawer type and the thermal relay calibration current, and start the test;

[0065] Step 3: The industrial control all-in-one computer sends the current setting value to the three-phase AC power supply through the LAN port according to the preset parameters, and then controls the relays through the relay matrix to complete the closing of the contactor in this circuit;

[0066] Step 4: The industrial control all-in-one computer starts the three-phase AC power supply through the LAN port to provide a large current to the drawer and starts timing. At the same time, the Hall current transmitter and the analog quantity acquisition card continuously collect the current value and send it to the industrial control all-in-one computer.

[0067] Step 5: The high current continues until the drawer thermal relay trips, the drawer circuit breaker disconnects the test main circuit, the current becomes zero, and the industrial control all-in-one computer records the moment the current disconnects.

[0068] Step 6: Timing the thermal relay's operating time to generate test results and a report;

[0069] Step 7: After the test is completed, the industrial control all-in-one computer controls the relays through the LAN port and relay matrix to disconnect the contactor in this circuit;

[0070] Step 8: The industrial control all-in-one computer displays that the test is complete. Pull the drawer out of the test slot or continue with other test items.

[0071] The present invention provides an intelligent maintenance device for low-voltage AC power distribution systems, used to verify the leakage current protection relay of a power distribution drawer: The industrial control computer of the power distribution drawer controls an AC programmable constant current power supply via a switch to output a preset three-phase unbalanced current. The sum of the three-phase currents is the preset operating value of the leakage current protection relay. The current passes through a customized pressure sensor housing and connects to the main contacts of the power distribution drawer under test and the internal leakage current protection relay. The software of the industrial control computer records the time for the AC programmable constant current power supply to output the current. At the same time, a current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to an analog signal processing box. The analog signal processing box converts the analog current signal into a digital signal and transmits it to a serial port server. The serial port server then transmits the digital signal to the industrial control computer via a switch. When the leakage current protection relay of the power distribution drawer operates, the industrial control computer detects that the current drops to zero through the current transmitter and stops timing, thus obtaining the operating current and operating time of the leakage current protection relay.

[0072] like Figure 5 As shown, the test principle and process for verifying the leakage protection relay of the distribution drawer using the intelligent maintenance device for low-voltage AC power distribution system provided by this invention are as follows:

[0073] Step 1: Insert the drawer into the test slot;

[0074] Step 2: Use the current transformer test cable to connect the leakage current transformer to the signal interface on the cabinet;

[0075] Step 3: Use the industrial control all-in-one computer to preset the parameters. The preset parameters include setting or selecting the test drawer type and the verification current of the leakage current transformer, and start the test.

[0076] Step 4: The industrial control all-in-one computer sends the current setting value to the single-phase AC power supply through the LAN port according to the preset parameters, and controls the relays through the LAN port and the relay matrix to complete the power supply of this auxiliary power supply.

[0077] Step 5: The industrial control all-in-one computer starts the single-phase AC power supply through the LAN port to provide current to the drawer and starts timing at the same time. Meanwhile, the Hall current transmitter and the analog quantity acquisition card continuously collect the current value and the on / off status of the main circuit and transmit them to the industrial control all-in-one computer.

[0078] Step 6: The current continues until the drawer leakage protection relay trips, the drawer circuit breaker disconnects the test main circuit, the main circuit is in the open state, and the industrial control all-in-one computer records the moment the main circuit is disconnected.

[0079] Step 7: Time the operation time and operating current of the leakage current protection relay, and generate test results and reports;

[0080] Step 8: After the test is completed, the industrial control all-in-one computer controls the relays through the LAN port and relay matrix to disconnect the auxiliary power supply for this circuit;

[0081] Step 9: The industrial control all-in-one computer displays that the test is complete. Pull the drawer out of the test slot and disconnect the leakage current transformer wiring.

[0082] The industrial control all-in-one computer uses a Windows operating system and a LabVIEW development environment. It includes: a user management module, a device under test (DUT) management module, a performance testing module, and a data management module, such as... Figure 6 As shown.

[0083] The user management module is used to set and control the usage permissions of administrators and testers;

[0084] The Test Component Management module is used for managing drawer cabinets and intermediate relays;

[0085] The performance testing module is used to perform contact tension testing, thermal relay calibration, leakage protection relay calibration, and intermediate relay calibration.

[0086] The data management module is used to save test data, test results and reports, view historical data, and export test data, test results and reports.

[0087] The intelligent maintenance device for low-voltage AC power distribution systems provided by this invention is used to perform intelligent maintenance on low-voltage AC power distribution systems, specifically including the following steps:

[0088] Step 1: Power on

[0089] Press the power button on the control panel. The maintenance device is powered on, and the login interface is displayed on the industrial control computer screen.

[0090] Step 2: Account Login

[0091] Log in using the username and password assigned by the administrator. After logging in, you can complete your basic personal information in the user settings.

[0092] Step 3: Insert the test piece

[0093] Depending on whether the device under test is a drawer cabinet or an intermediate relay, select the corresponding interface position. For drawer cabinets, insert the interface with the matching specification at the bottom; for intermediate relays, insert the interface on the upper right intermediate relay base.

[0094] Step 4: Automatic Detection

[0095] Once you enter the performance testing interface, select the model of the component under test from the drop-down menu, and click "Start Testing". The system will then automatically begin a comprehensive test based on the test cases. The system will apply the corresponding stimuli to the inputs in sequence and measure the output results. The testing process displays the progress of the test and the information of the current test item.

[0096] Step 5: Generate a report

[0097] After a comprehensive test is completed, the test results data can be automatically generated into a Word version test report, which can be printed on A4 paper by connecting to a printer; or exported using a USB interface.

[0098] Step 6: End shutdown

[0099] After the test is completed, remove the power distribution drawer or intermediate relay, click the power off button on the software interface to shut down the system computer, and press the power switch on the table to cut off the power supply to the test system.

[0100] The present invention has been described in detail above with reference to the accompanying drawings and embodiments. However, the present invention is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the spirit of the present invention. All contents not described in detail in the present invention can be derived from existing technologies.

Claims

1. An intelligent maintenance device for a low-voltage AC power distribution system, characterized in that, The device includes: A custom pressure sensor is used to hold the main contacts of the distribution drawer in place. Based on the pressure of the main contacts of the distribution drawer being held in place, a voltage analog signal representing the clamping force of the main contacts is generated and transmitted to the current transmitter. An AC programmable constant current power supply is used to output a preset current to the main contacts and internal main circuit of the power distribution drawer under test; The current transmitter is used to acquire the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test, and transmit the voltage analog signal of each main contact of the power distribution drawer under test and the current analog signal flowing into the power distribution drawer under test to the analog quantity processing box. The analog signal processing box is used to convert the analog voltage signals of each main contact of the power distribution drawer under test and the analog current signals of the power distribution drawer under test into digital signals, and then transmit the digital signals to the serial port server. A serial port server is used to transmit digital signals to an industrial control all-in-one computer via a switch. An industrial control all-in-one computer is used to control the output current of an AC programmable constant current power supply, record and display digital signals, and record the time of the AC programmable constant current power supply output current. The device is used to verify the clamping force of the main contacts of the distribution drawer in a low-voltage AC power distribution system: each main contact of the distribution drawer clamps the corresponding customized pressure sensor of the intelligent maintenance device of the AC power distribution system. The strain gauge inside each customized pressure sensor is subjected to force, generating a corresponding voltage analog signal that is transmitted to the current transmitter. The current transmitter collects the voltage analog signal and transmits it to the analog quantity processing box. The analog quantity processing box processes the voltage analog signal representing the pressure and converts it into a digital signal. The analog quantity processing box transmits the digital signal representing the clamping force of the main contacts to the industrial control all-in-one computer through a serial port server and switch. The industrial control all-in-one computer records and displays the pressure data and judges whether the clamping force is qualified according to the criteria. The device is used to calibrate the thermal relay of a power distribution drawer: the industrial control computer of the power distribution drawer controls the AC programmable constant current power supply to output a preset current through a switch. The preset current value is the preset operating current value of the thermal relay. At this time, the main contact of the power distribution drawer is stuck in the test slot of the intelligent maintenance device for low-voltage AC power distribution system, which is a customized pressure sensor. The current output by the AC programmable constant current power supply passes through the contactor and the housing of the customized pressure sensor to the main contact and internal main circuit of the power distribution drawer under test. The industrial control computer records the time when the AC programmable constant current power supply outputs the current. At the same time, the current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to the analog signal processing box. The analog signal processing box processes the analog current signal and converts it into a digital signal. The analog signal processing box transmits the digital signal to the industrial control computer through a serial server and a switch. When the thermal relay of the power distribution drawer operates, that is, when the main circuit is disconnected, the industrial control computer detects that the current drops to zero through the current transmitter and stops timing, thus obtaining the operating current and operating time of the thermal relay. The device is used to verify the leakage current protection relay of the power distribution drawer: the industrial control computer of the power distribution drawer controls the AC programmable constant current power supply to output a preset three-phase unbalanced current through a switch. The sum of the three-phase currents is the preset operating value of the leakage current protection relay. The current passes through the housing of a customized pressure sensor and is connected to the main contacts of the power distribution drawer under test and the internal leakage current protection relay. The software of the industrial control computer records the time of the AC programmable constant current power supply outputting the current. At the same time, the current transmitter collects the analog current signal flowing into the power distribution drawer under test and transmits it to the analog quantity processing box. The analog quantity processing box converts the analog current signal into a digital signal and transmits it to the serial port server. The serial port server then transmits the digital signal to the industrial control computer through the switch. When the leakage current protection relay of the power distribution drawer operates, the industrial control computer detects that the current drops to zero through the current transmitter and stops timing, thus obtaining the operating current and operating time of the leakage current protection relay.

2. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The AC programmable constant current power supply includes a three-phase AC power supply and a single-phase AC power supply; the three-phase AC power supply is a three-phase 0~200A AC power supply used for thermal relay calibration; the single-phase AC power supply is a single-phase 0~10A AC power supply used for leakage protection relays.

3. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The device also includes a relay matrix, used to control the relays to close and open the contactor in this circuit, or to control the relays to supply and disconnect the auxiliary power supply in this circuit.

4. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The device also includes test slots for accommodating the power distribution drawer under test, and a custom pressure sensor is installed in the test slots; the test slots include 8E / 2 test device fixing positions, 4E test device fixing positions, 6E test device fixing positions, and 8E test device fixing positions.

5. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The device also includes a power switch button and a power indicator light; the power switch button is used to power on and off the device; the power indicator light is used to indicate whether the device is connected to a working power source.

6. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The device also includes a relay base and a banana plug; the relay base is used for calibrating the intermediate relay; the banana plug is used for the interface of the leakage protection relay to the external current transformer.

7. The intelligent maintenance device for a low-voltage AC power distribution system according to claim 1, characterized in that, The industrial control all-in-one computer includes: The user management module is used to set and control the usage permissions of administrators and testers; The tested component management module is used for managing drawer cabinets and intermediate relays; The performance testing module is used to perform contact tension testing, thermal relay verification, leakage protection relay verification, and intermediate relay verification. The data management module is used to save test data, test results and reports, view historical data, and export test data, test results and reports.

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