Miniature circuit breaker magnetic trip characteristic test system

Abstract

The micro circuit breaker magnetic release characteristic test system relates to the technical field of magnetic release characteristic test, and comprises a control module, a power module, an IGBT module, a current transformer, an anti-parallel thyristor and a single-phase transformer. The control module is used for collecting the power voltage waveform of the power module, and controlling the IGBT module to work off when the waveform of the power voltage reaches a preset phase, so as to control the residual magnetism of the single-phase transformer to be minimum. The control module is also used for obtaining each excitation inrush current in the loop of the micro short circuit breaker under different closing angles, and obtaining the measured circuit breaker release current and the release time of the micro circuit breaker. The excitation inrush current generated during the no-load charging of the transformer is used as the micro circuit breaker release current, the different sizes of the excitation inrush current under different closing angles generate different sizes of the release current, and only the control of the thyristor conduction time is needed, so that the complexity of the operation of the combination of multiple resistances in series and parallel in the traditional magnetic release calibration device is avoided.

Description

Technical Field

[0001] This disclosure relates to the field of magnetic tripping characteristic testing technology, and in particular to a magnetic tripping characteristic testing system for miniature circuit breakers. Background Technology

[0002] Currently, the importance of DC power supply systems in power plants and substations as the power source for relay protection and safety automatic devices, speed governors, excitation, and switch control is self-evident. Most DC power supply systems adopt a radial power supply pattern, typically involving three levels of distribution from batteries to the electrical equipment. Each level usually uses DC circuit breakers as protective devices, with a coordination level of 2 to 4 levels. This raises the issue of coordination of selective protection between the upper and lower levels of DC circuit breakers, directly affecting whether DC power supply faults can be controlled to a minimum to prevent damage to the DC power supply system, the escalation of accidents, and equipment failure.

[0003] Currently, the magnetic tripping characteristic test of miniature circuit breakers is mainly achieved by connecting the DC circuit breaker in series with the load resistor and adjusting the load resistor to obtain a large current. This method results in a large circuit load current and a large amount of heat generation, which places high demands on power supply equipment, series resistors, cables, etc. The combination of series and parallel resistors is complex and poses certain safety risks. Summary of the Invention

[0004] This disclosure aims to at least partially address one of the technical problems in the related art.

[0005] The first aspect of this disclosure provides a magnetic tripping characteristic testing system for a miniature circuit breaker, comprising: a control module, a power supply module, an IGBT module, a current transformer, anti-parallel thyristors, and a single-phase transformer, wherein... The control module is used to acquire the power supply voltage waveform of the power supply module, and control the IGBT module to turn off when the power supply voltage waveform reaches a preset phase, and control the residual magnetism of the single-phase transformer to be minimized. The control module is also used to acquire the inrush currents in the circuit where the miniature circuit breaker under test is located at different closing angles, as well as the measured tripping current of the circuit breaker and the tripping time of the miniature circuit breaker under test.

[0006] Optionally, the control module includes a digital input acquisition unit, an analog input sampling unit, an output control unit, a microprocessor unit, and a host computer management unit. The microprocessor unit and the host computer management unit communicate via RS485. The digital input unit, the analog sampling unit, and the output control unit are connected to the microprocessor unit via an internal bus.

[0007] Optionally, the analog sampling unit is used to acquire the secondary current and power supply voltage of the current transformer and to perform analog-to-digital conversion; The switch quantity acquisition unit is used to acquire the on / off signals of the circuit breaker under test.

[0008] Optionally, the control output unit is used to receive the microprocessor signal sent by the microprocessor unit, and convert and amplify the microprocessor signal to drive and control the thyristor and IGBT semiconductor devices.

[0009] Optionally, the host computer management unit includes a touch screen and a keyboard, wherein, The host computer management unit is used for parameter setting, command issuance, and data display.

[0010] Optionally, the control module is further configured to: Obtain the inrush current of single-phase transformers of different capacities at different closing angles; Establish a mapping table for each of the single-phase transformers, wherein the mapping table contains the correspondence between the inrush current and the closing angle.

[0011] Optionally, the current transformer is connected to the analog sampling unit. The anti-parallel thyristor is connected to the output control unit.

[0012] Optionally, the microprocessor unit is used to receive the closing angle sent by the host computer management unit to close the circuit and record the inrush current in the circuit.

[0013] Optionally, the microprocessor unit is further configured to: After closing the circuit, the residual magnetism of the single-phase transformer is minimized.

[0014] Optionally, the analog sampling unit is used to collect the circuit breaker tripping current flowing through the miniature circuit breaker under test, and to measure the circuit breaker tripping current and the tripping time of the miniature circuit breaker under test.

[0015] The magnetic tripping characteristic testing system for miniature circuit breakers disclosed herein has the following beneficial effects: The miniature circuit breaker magnetic tripping characteristic testing system in this embodiment utilizes the inrush current generated when the transformer is under no-load charging as the tripping current of the miniature circuit breaker. The inrush current has rapid decay, low circuit heat generation, low requirements for test equipment, and safe test process. Different tripping currents are generated by utilizing the different inrush currents at different closing angles. This can be achieved by simply controlling the thyristor conduction time, avoiding the complexity of traditional magnetic tripping verification devices that combine multiple resistors in series and parallel. By controlling the transformer opening time to adjust the transformer residual magnetism, the dispersion of the excitation current when the transformer is under no-load charging and closing at the same angle is small, improving test accuracy and success rate. The system can test a wide range of miniature circuit breaker tripping power supplies, and can achieve characteristic testing of circuit breakers of different capacity levels simply by changing the transformer of different capacity.

[0016] Additional aspects and advantages of this disclosure will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this disclosure. Attached Figure Description

[0017] The above and / or additional aspects and advantages of this disclosure will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram of the structure of a magnetic tripping characteristic testing system for a miniature circuit breaker provided in an embodiment of the present disclosure; Figure 2 This is a schematic diagram of the structure of another miniature circuit breaker magnetic tripping characteristic testing system provided in an embodiment of the present disclosure, wherein 1-power supply module; 2-circuit breaker under test; 4-current transformer; 5-anti-parallel thyristor; 6-single-phase transformer; 7-digital input unit; 8-analog sampling unit; 9-output control unit; 10-microprocessor unit; 11-host computer; 14-IGBT module; 15-control module. Detailed Implementation

[0018] Embodiments of this disclosure are described in detail below. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this disclosure, and should not be construed as limiting this disclosure.

[0019] The following description, with reference to the accompanying drawings, describes a miniature circuit breaker magnetic tripping characteristic testing system according to an embodiment of the present disclosure.

[0020] It should be noted that inrush current is caused by the inability of the magnetic flux in the core of a transformer to change abruptly when it is put into operation under no-load conditions. This results in the appearance of a non-periodic component of the magnetic flux, which saturates the transformer core and causes a sharp increase in the excitation current. The maximum value of the transformer inrush current can reach 6 to 8 times the rated current of the transformer, and is related to the transformer's capacity. The miniature circuit breaker magnetic trip characteristic testing system of this disclosure mainly achieves residual magnetism control and inrush current magnitude control by controlling the transformer's no-load opening angle and closing angle, thereby adjusting the current magnitude to test the magnetic trip characteristic of the miniature circuit breaker.

[0021] Figure 1 This is a schematic diagram of a magnetic tripping characteristic testing system for a miniature circuit breaker provided in an embodiment of this disclosure.

[0022] like Figure 1 As shown, the miniature circuit breaker magnetic tripping characteristic testing system includes: a control module 15, a power supply module 1, an IGBT module 14, a current transformer 4, an anti-parallel thyristor 5, and a single-phase transformer 6. The control module of the miniature circuit breaker magnetic trip characteristic test system is used to acquire the power supply voltage waveform of the power supply module of the miniature circuit breaker magnetic trip characteristic test system, and control the IGBT module of the miniature circuit breaker magnetic trip characteristic test system to cut off when the power supply voltage waveform of the miniature circuit breaker magnetic trip characteristic test system reaches the preset phase, and control the residual magnetism of the single-phase transformer of the miniature circuit breaker magnetic trip characteristic test system to be minimized.

[0023] The power supply voltage waveform can be an AC sine wave.

[0024] The preset phase can be a 90° phase, and there is no limitation here.

[0025] Specifically, the control module 15, power supply module 1, IGBT module 14, current transformer 4, anti-parallel thyristor 5, and single-phase transformer 6 can constitute the main test circuit.

[0026] An IGBT (Insulated Gate Bipolar Transistor) module is an electronic device that integrates an IGBT (Insulated Gate Bipolar Transistor) and other related components. To shut down an IGBT module, the following steps can be taken: Disconnect control signal: Disconnect the control or drive signal of the IGBT to stop applying control voltage to its gate. Disconnect power source: Cut off the power source on the IGBT module, usually the power switch in its power input line. Reduce temperature: IGBT modules generate heat during operation. To ensure safe shutdown, their temperature should be reduced to a safe range using appropriate heat dissipation mechanisms.

[0027] Specifically, by minimizing the residual magnetism of a single-phase transformer, the dispersion of inrush current at the same angle can be minimized.

[0028] Optionally, the control module of the miniature circuit breaker magnetic tripping characteristic test system is also used to acquire the inrush currents in the circuit where the miniature circuit breaker under test is located at different closing angles, as well as the measured tripping current of the circuit breaker and the tripping time of the miniature circuit breaker under test in the miniature circuit breaker magnetic tripping characteristic test system.

[0029] Optionally, an inrush current test can be performed at each closing angle. Connect a current sensor or current clamp meter to the circuit containing the miniature circuit breaker under test, then close the circuit and record the corresponding inrush current value.

[0030] It should be noted that the microcontroller control module includes: a digital input acquisition unit, which acquires the on / off signals of the circuit breaker under test; an analog input sampling unit, which acquires the secondary current of the current transformer in the circuit and the power supply voltage and performs analog-to-digital conversion; an output control unit, which converts and amplifies the microprocessor signals to drive and control thyristors and IGBT semiconductor devices; a microprocessor unit, which mainly performs signal acquisition from upstream to downstream, power supply voltage phase detection, data processing, logic operations, and command output; and a host computer management unit, which mainly consists of a touch screen and a keyboard, and performs parameter setting, command issuance, and result and data display.

[0031] Optionally, the control module of the miniature circuit breaker magnetic tripping characteristic testing system includes a digital input acquisition unit, an analog input sampling unit, an output control unit, a microprocessor unit, and a host computer management unit. The microprocessor unit and the host computer management unit of the miniature circuit breaker magnetic tripping characteristic testing system communicate via RS485. The host computer management unit also communicates with the microcontroller control and testing module via RS485, uploading and displaying test data, sending preset parameters such as closing angles to the microcontroller testing module, and sending test control commands to the microcontroller control unit. RS485 is a serial communication protocol and a physical layer standard. It supports multi-point and long-distance communication and has strong anti-interference capabilities.

[0032] The digital input unit, analog sampling unit, and output control unit of the miniature circuit breaker magnetic tripping characteristic test system are connected to the microprocessor unit of the miniature circuit breaker magnetic tripping characteristic test system via an internal bus.

[0033] Optionally, the analog sampling unit of the miniature circuit breaker magnetic tripping characteristic test system is used to collect the secondary current and power supply voltage of the current transformer and realize analog-to-digital conversion. The switch quantity acquisition unit of the miniature circuit breaker magnetic tripping characteristic test system is used to acquire the on / off signals of the circuit breaker under test.

[0034] It should be noted that, in addition to the above, the magnitude of the inrush current is related to at least one of the following factors.

[0035] (1) Power supply voltage: After the transformer is switched on, the amplitude of the forced magnetic flux in the iron core is greater when the power supply voltage is higher, and the inrush current is greater.

[0036] (2) Closing angle: In an AC circuit, the magnetic flux Φ always lags the voltage U by 90° phase angle. When the closing phase angle = 0°, the inrush current is the largest. When the closing phase angle = 90°, the inrush current is zero.

[0037] (3) Residual magnetism: The greater the residual magnetism in the transformer core before closing, the greater the inrush current. In addition, the inrush current is greater when the direction of the residual magnetism is the same as the direction after closing.

[0038] It should be noted that the residual magnetism of the transformer core is related to the phase angle of the AC voltage at the moment of power failure. The residual magnetism is minimal when the phase angle is 90° and maximal when the phase angle is 0°.

[0039] Optionally, the control output unit of the miniature circuit breaker magnetic tripping characteristic test system is used to receive the microprocessor signal sent by the microprocessor unit of the miniature circuit breaker magnetic tripping characteristic test system, and convert and amplify the microprocessor signal of the miniature circuit breaker magnetic tripping characteristic test system to drive and control the thyristor and IGBT semiconductor devices.

[0040] Optionally, the host computer management unit of the miniature circuit breaker magnetic tripping characteristic testing system includes a touch screen and a keyboard. The host computer management unit refers to the unit within the control module responsible for communication with the host computer, data processing, and control operations. As the main control core of the entire control module, it undertakes the functions of data exchange, monitoring, and control with the host computer. The main functions and features of the host computer management unit are as follows: Communication with the host computer: The host computer management unit communicates with the host computer through various communication interfaces (such as Ethernet, serial port, etc.) to achieve data transmission and exchange. It can receive commands, parameter settings, and data requests from the host computer, and send status, monitoring data, and alarm information to the host computer. Data processing and storage: The host computer management unit can process and analyze data collected from the lower-level devices. It can perform statistical analysis, calculation, filtering, and storage of data, generating reports or trend curves for reference by the host computer or operators. Control and scheduling: The host computer management unit has the ability to control lower-level devices, executing corresponding control operations such as switching devices on and off and adjusting parameters under the instructions issued by the host computer. It can also execute automated control and scheduling tasks according to preset logic and strategies. Real-time monitoring and remote access: The host computer management unit can monitor the status, operating data, and alarm information of the slave devices in real time and display this information to the operators through the host computer. In addition, it supports remote access, allowing remote monitoring and operation of slave devices via network connection. Fault diagnosis and fault recording: The host computer management unit is equipped with fault diagnosis function, which can automatically detect, diagnose, and record faults in the system and equipment, provide fault alarms and maintenance prompts, help quickly troubleshoot faults, and improve the reliability and maintainability of the system. The host computer management unit of the miniature circuit breaker magnetic tripping characteristic testing system is used for parameter setting, command issuance, and data display.

[0041] Optionally, the control module of the miniature circuit breaker magnetic tripping characteristic testing system is also used for: Obtain the inrush current of single-phase transformers of different capacities at different closing angles; Establish a mapping table for the single-phase transformer of each miniature circuit breaker magnetic trip characteristic test system. The mapping table of miniature circuit breaker magnetic trip characteristic test system contains the correspondence between the inrush current and the closing angle of the miniature circuit breaker magnetic trip characteristic test system.

[0042] Optionally, the current transformer of the miniature circuit breaker magnetic tripping characteristic test system is connected to the analog sampling unit of the miniature circuit breaker magnetic tripping characteristic test system. The anti-parallel thyristor of the miniature circuit breaker magnetic tripping characteristic test system is connected to the output control unit of the miniature circuit breaker magnetic tripping characteristic test system.

[0043] Optionally, the microprocessor unit of the miniature circuit breaker magnetic trip characteristic test system receives the closing angle of the miniature circuit breaker magnetic trip characteristic test system sent by the host computer management unit and performs closing, and records the inrush current in the circuit of the miniature circuit breaker magnetic trip characteristic test system. The microprocessor module receives different closing angles from the host computer management unit to achieve single-phase transformer closing at different phase angles. The main circuit current at the moment of closing is collected by the current transformer and sent to the analog sampling unit. The analog sampling unit processes the data through analog-to-digital conversion and transmits it to the processor module, thus obtaining the current (inrush current) of different magnitudes obtained in the test main circuit at the moment of closing. For the same single-phase transformer, the inrush current at different closing angles is obtained through multiple tests, thereby quantitatively obtaining the correspondence between the inrush current and the closing angle. After each single-phase transformer closing, residual magnetism control should be repeated to reduce the residual magnetism of the single-phase transformer as quickly as possible.

[0044] The method can first acquire the on / off signal of the circuit breaker under test by the switch quantity acquisition unit, and acquire the current flowing through the miniature circuit breaker when it trips by the analog quantity sampling unit. The on / off signal of the miniature circuit breaker under test is transmitted to the microprocessor module through the switch quantity acquisition unit. Then, the relationship between the closing phase angle and the inrush current is tested. Different closing times (closing phase angles) are set in the host computer management unit. The closing phase angle is gradually adjusted from 90° to 0° until the miniature circuit breaker trips. The tripping current of the circuit breaker and the tripping time of the miniature circuit breaker are measured. The magnetic tripping characteristics of the miniature circuit breaker are obtained by repeated testing.

[0045] Optionally, the microprocessor unit of the miniature circuit breaker magnetic tripping characteristic testing system is also used for: After closing the circuit, the single-phase transformer with the minimum residual magnetism was controlled by the magnetic tripping characteristic test system of the miniature circuit breaker.

[0046] Optionally, the analog sampling unit of the miniature circuit breaker magnetic tripping characteristic test system is used to collect the circuit breaker tripping current flowing through the miniature circuit breaker under test in the miniature circuit breaker magnetic tripping characteristic test system, and to measure the circuit breaker tripping current and tripping time of the miniature circuit breaker under test in the miniature circuit breaker magnetic tripping characteristic test system.

[0047] The miniature circuit breaker magnetic tripping characteristic testing system in this embodiment utilizes the inrush current generated when the transformer is under no-load charging as the tripping current of the miniature circuit breaker. The inrush current has rapid decay, low circuit heat generation, low requirements for test equipment, and safe test process. Different tripping currents are generated by utilizing the different inrush currents at different closing angles. This can be achieved by simply controlling the thyristor conduction time, avoiding the complexity of traditional magnetic tripping verification devices that combine multiple resistors in series and parallel. By controlling the transformer opening time to adjust the transformer residual magnetism, the dispersion of the excitation current when the transformer is under no-load charging and closing at the same angle is small, improving test accuracy and success rate. The system can test a wide range of miniature circuit breaker tripping power supplies, and can achieve characteristic testing of circuit breakers of different capacity levels simply by changing the transformer of different capacity.

[0048] It should be understood that various parts of this disclosure can be implemented in hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods can be implemented in software or firmware stored in memory and executed by a suitable instruction execution system. For example, if implemented in hardware as in another embodiment, it can be implemented using any one or a combination of the following techniques known in the art: discrete logic circuits having logic gates for implementing logical functions on data signals, application-specific integrated circuits (ASICs) having suitable combinational logic gates, programmable gate arrays (PGAs), field-programmable gate arrays (FPGAs), etc.

[0049] Those skilled in the art will understand that all or part of the steps of the methods in the above embodiments can be implemented by a program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, the program includes one or a combination of the steps of the method embodiments.

[0050] Furthermore, the functional units in the various embodiments of this disclosure can be integrated into a processing module, or each unit can exist physically separately, or two or more units can be integrated into a module. The integrated module can be implemented in hardware or as a software functional module. If the integrated module is implemented as a software functional module and sold or used as an independent product, it can also be stored in a computer-readable storage medium.

[0051] The storage medium mentioned above can be a read-only memory, a disk, or an optical disk, etc. Although embodiments of the present disclosure have been shown and described above, it is to be understood that the above embodiments are exemplary and should not be construed as limiting the present disclosure. Those skilled in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present disclosure.

Claims

1. A magnetic tripping characteristic testing system for miniature circuit breakers, characterized in that, include: The system includes a control module, a power supply module, an IGBT module, a current transformer, anti-parallel thyristors, and a single-phase transformer. The power module is used to provide power voltage; The control module is used to acquire the power supply voltage waveform of the power supply module, and control the IGBT module to turn off when the power supply voltage waveform reaches a preset phase, and control the residual magnetism of the single-phase transformer to be minimized. The control module is also used to acquire the inrush currents in the circuit of the miniature circuit breaker under test at different closing angles of the single-phase transformer, as well as the measured tripping current of the circuit breaker and the tripping time of the miniature circuit breaker under test. The control module includes a digital input acquisition unit, an analog input sampling unit, an output control unit, a microprocessor unit, and a host computer management unit. The microprocessor unit and the host computer management unit communicate via RS485. The digital input acquisition unit, the analog input sampling unit, and the output control unit are connected to the microprocessor unit via an internal bus. The microprocessor unit is used for acquiring signals from above and below, detecting power supply voltage phase, processing data, performing logic operations, and outputting commands. The current transformer is connected to the analog quantity sampling unit. The anti-parallel thyristor is connected to the output control unit; The analog sampling unit is used to collect the secondary current and power supply voltage of the current transformer and to perform analog-to-digital conversion. The switch quantity acquisition unit is used to acquire the on / off signal of the circuit breaker under test; The output control unit is used to receive the microprocessor signal sent by the microprocessor unit, and convert and amplify the microprocessor signal to drive and control the thyristor and IGBT semiconductor devices.

2. The system according to claim 1, characterized in that, in, The host computer management unit includes a touch screen and a keyboard, wherein, The host computer management unit is used for parameter setting, command issuance, and data display.

3. The system according to claim 1, characterized in that, The control module is also used for: Obtain the inrush current of single-phase transformers of different capacities at different closing angles; Establish a mapping table for each of the single-phase transformers, wherein the mapping table contains the correspondence between the inrush current and the closing angle.

4. The system according to claim 1, characterized in that, The microprocessor unit is used to receive the closing angle sent by the host computer management unit to close the circuit and record the inrush current in the circuit.

5. The system according to claim 4, characterized in that, The microprocessor unit is also used for: After closing the circuit, the residual magnetism of the single-phase transformer is minimized.

6. The system according to claim 1, characterized in that, The analog sampling unit is used to collect the circuit breaker tripping current flowing through the miniature circuit breaker under test, and to measure the circuit breaker tripping current and the tripping time of the miniature circuit breaker under test.

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