Fuse overload interruption method and apparatus

Abstract

The application relates to the technical field of power equipment detection, in particular to a fuse overload breaking method and device, which comprises the following steps: acquiring port voltage data and pre-arc time, combining a fuse resistance to calculate a critical melting voltage of a fuse; setting test parameters of the fuse based on the critical melting voltage; checking whether a test sample state meets a low-voltage loop condition; if yes, comparing and analyzing the port voltage data with the critical melting voltage; when the port voltage data approaches the critical melting voltage and a switching condition is met, switching the fuse from the low-voltage loop to a full-voltage test loop; if the fuse reaches a fuse breaking condition in the full-voltage test loop, the fuse is rapidly fused; if the test sample state does not meet the low-voltage loop condition, adjusting a contactor state to a target position for testing. Therefore, the problems of low success rate of fuse overload breaking experiments in the prior art are solved.

Description

Technical Field

[0001] This application relates to the field of power equipment testing technology, and in particular to a method and apparatus for overload breaking of a fuse. Background Technology

[0002] In power systems, the overload breaking capacity of low-voltage fuses is crucial for the safe and stable operation of the system. Industry standards clearly specify their core indicators such as rated values ​​and time-current characteristics. However, fuse performance is significantly affected by factors such as ambient temperature, altitude, installation conditions, and usage type. For example, high temperatures can change the breaking time, and high altitudes can affect the arc extinguishing effect.

[0003] Traditional overload breaking test equipment has limitations, including poor current loading accuracy and difficulty in simulating actual current changes. Its environmental simulation capabilities are also weak, failing to accurately reflect the impact of different environments on fuse performance and thus failing to meet the high-performance and high-reliability requirements of modern power systems.

[0004] With industrial development and the increasing scale and complexity of power systems, the performance requirements for fuses are rising, making intelligent control technology an inevitable trend. It can achieve automated testing and intelligent data analysis, improving testing efficiency and result accuracy, and supporting fuse performance optimization. Different application scenarios have significantly different requirements for fuse performance and testing, such as the complexity of industrial power grids and the unique operating conditions in the new energy field. Therefore, there is an urgent need for testing equipment and control methods with greater adaptability and specificity.

[0005] Currently, there are numerous studies on overload breaking tests of low-voltage fuses, with each invention having its own characteristics. Existing technology CN114594411A discloses a system for detecting the pre-arc time-current characteristics of a fuse element. This system determines the fusing time by detecting the characteristics of the fuse element, but it has limitations. It mainly relies on current feedback and does not consider the influence of multiple factors such as materials and environment on the fusing process. Furthermore, the data acquisition is singular, lacking the recording and analysis of key parameters. The fusing time measured under complex operating conditions is prone to deviation, making it difficult to provide comprehensive and reliable data support.

[0006] The existing technology, as disclosed in the journal "Analysis of Fuse Overload Breaking Test System and Test Method" by Li Saisai, Miao Benjian, Zhang Dafeng, et al., presents an analysis of the fuse overload breaking test system and test method. This system integrates a more comprehensive data acquisition system and provides a more complete analysis of parameters such as slope k and fusing time t. However, it only considers a few factors affecting fusing time, and the analysis of parameters is not detailed or thorough. This leads to poor accuracy in determining fusing time under complex and variable actual working conditions, with a significant deviation between the determined fusing time and the actual required fusing time, making it difficult to accurately and effectively protect the circuit. Furthermore, precise control of ∆t is quite challenging in practical applications. Therefore, while the research based on this theory has important guiding significance at the theoretical level, its application in actual working conditions is limited by objective factors that are difficult to precisely control, introducing a certain degree of error. Summary of the Invention

[0007] This application provides a method and apparatus for overload breaking of a fuse, in order to solve the problems of low success rate of overload breaking experiments of fuses in the prior art, inaccurate timing of the test sample switching from low voltage to full voltage circuit, and large error in test results.

[0008] The first aspect of this application provides a fuse overload breaking method, comprising the following steps: acquiring port voltage data and arc pre-arc time; calculating the critical melting voltage of the fuse based on the port voltage data and the arc pre-arc time, combined with the fuse element resistance; setting test parameters for different types of fuses based on the critical melting voltage, checking whether the test sample state meets the low-voltage circuit conditions; if the test sample state meets the low-voltage circuit conditions, comparing and analyzing the port voltage data with the critical melting voltage; when the port voltage data is close to the critical melting voltage and meets the switching conditions, closing KM1 and KM2, opening KM3 and KM4, and switching the fuse from the low-voltage circuit to the full-voltage test circuit; if the fuse reaches the melting condition in the full-voltage test circuit, it melts rapidly; if the test sample state does not meet the low-voltage circuit conditions, adjusting the contactor state to the target position for testing.

[0009] Optionally, based on the port voltage data and the pre-arc time, combined with the fuse resistance, the critical melting voltage of the fuse is calculated, and the specific formula for the critical melting voltage is as follows:

[0010] ;

[0011] in, For the expected test current, The resistivity of metals at room temperature Where is the melt radius, The length of the melt. For the index, Temperature coefficient of resistance For the arc pre-arc time, It is the specific heat capacity of the melt. The density of the melt. It is the voltage across the two ends of the melt at room temperature.

[0012] Optionally, the test parameters include recovery voltage, expected test current and current tolerance, and the low-voltage circuit condition is that contactors KM1 and KM2 are open and KM3 and KM4 are closed.

[0013] Optionally, the switching conditions include the port voltage being within a preset voltage threshold range corresponding to the fuse specification, the current change rate being within a preset reasonable range, and the arc pre-arc time reaching or approaching a preset arc pre-arc time threshold.

[0014] Optionally, the fusing conditions include electrical parameters, thermal effects, and time conditions, wherein the electrical parameters include, but are not limited to, fuse port voltage, current intensity, and current change rate; and the thermal effects include the melt temperature and its heat accumulation.

[0015] Optionally, switching the fuse from a low-voltage circuit to a full-voltage test circuit further includes: acquiring the voltage and current changes at the moment of disconnection; and automatically adjusting the absorption parameters based on the voltage and current changes to convert the excess energy generated during the disconnection process into electrical energy and store it in a matching energy storage device, or convert it into heat energy and dissipate it through a heat dissipation component.

[0016] A second aspect of this application provides a fuse overload breaking device, comprising: an acquisition module for acquiring port voltage data and arc pre-arc time; a calculation module for calculating the critical melting voltage of the fuse based on the port voltage data and the arc pre-arc time, combined with the fuse element resistance; and a fusing module for setting test parameters for different types of fuses based on the critical melting voltage, checking whether the test sample state meets the low-voltage circuit conditions, and if the test sample state meets the low-voltage circuit conditions, comparing the port voltage data with the critical melting voltage, and when the port voltage data is close to the critical melting voltage and meets the switching conditions, closing KM1 and KM2, opening KM3 and KM4, and switching the fuse from the low-voltage circuit to the full-voltage test circuit; if the fuse reaches the fusing condition in the full-voltage test circuit, it rapidly fuses; if the test sample state does not meet the low-voltage circuit conditions, adjusting the contactor state to the target position for testing.

[0017] Optionally, it also includes: a full-voltage circuit module, a conversion unit, and a low-voltage constant current source submodule. The full-voltage circuit module consists of a full-voltage side circuit breaker, an adjustable transformer, a rectifier cabinet, an adjustable load reactor, an adjustable load resistor, and a full-voltage side contactor group. The conversion unit includes four contactors: KM1 and KM2 control the on / off of the full-voltage side circuit, and KM3 and KM4 control the low-voltage constant current source side circuit. The low-voltage constant current source submodule is used to provide a stable current to the fuse, enabling the fuse to operate in a low-voltage, safe environment during the initial stage of the test, avoiding premature melting due to high-voltage surges, and ensuring stable and repeatable testing.

[0018] Therefore, this application has at least the following beneficial effects:

[0019] This application's embodiments calculate the critical melting voltage by acquiring port voltage data and arc pre-arc time, combined with the fuse resistance-temperature relationship, to accurately determine the switching timing. Customized test parameters are set for different types of fuses, effectively avoiding errors caused by improper switching timing and parameter mismatch, thus improving test accuracy and reliability. Before testing, the sample status is checked; if the low-voltage circuit conditions are not met, the contactor status is adjusted to ensure test safety. After switching to the full-voltage circuit, the fusing condition is monitored in real time, enabling rapid fusing detection and timely recording of key data. This not only reduces test result errors but also reduces manual intervention through automated operation, shortening the test cycle and improving test efficiency. Simultaneously, it enhances test versatility and flexibility, reducing development costs. Furthermore, it provides detailed evidence for fuse performance optimization, assisting researchers in targeted improvements to materials and structures, enhancing the overall performance and reliability of fuses. Therefore, it solves the problems of low success rate in fuse overload breaking tests, inaccurate timing of switching from low-voltage to full-voltage circuits, and large test result errors in existing technologies.

[0020] Additional aspects and advantages of this application 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 application. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the following description of the embodiments taken in conjunction with the accompanying drawings, wherein:

[0022] Figure 1 This is a flowchart of a fuse overload breaking method according to an embodiment of this application;

[0023] Figure 2 This is a schematic diagram of the current-voltage test results over 12 seconds according to an embodiment of this application;

[0024] Figure 3 This is a schematic diagram of the current-voltage test results at 18 seconds according to an embodiment of this application;

[0025] Figure 4 This is a schematic diagram of the current-voltage test results over 25 seconds according to an embodiment of this application;

[0026] Figure 5 This is a flowchart of a fuse overload breaking method according to an embodiment of this application;

[0027] Figure 6 This is a schematic diagram of a fuse overload breaking device according to an embodiment of this application;

[0028] Figure 7 This is a schematic diagram of a fuse overload breaking device according to an embodiment of this application. Detailed Implementation

[0029] The embodiments of this application are described in detail below. Examples of these embodiments are shown 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 application, and should not be construed as limiting this application.

[0030] The following description, with reference to the accompanying drawings, describes a fuse overload breaking method and apparatus according to embodiments of this application. Addressing the problem of large test result errors mentioned in the background art, this application provides a fuse overload breaking method. In this method, by acquiring port voltage data and arc pre-arc time, and combining this with the fuse resistance-temperature relationship to calculate the critical melting voltage, the switching timing is accurately determined. Customized test parameters are set for different types of fuses, effectively avoiding errors caused by improper switching timing and parameter mismatch, thus improving test accuracy and reliability. Before testing, the sample state is checked; if the low-voltage circuit conditions are not met, the contactor state is adjusted to ensure test safety. After switching to the full-voltage circuit, the fusing condition is monitored in real time, achieving rapid fusing detection and timely recording of key data. This not only reduces test result errors but also reduces manual intervention through automated operation, shortens the test cycle, and improves test efficiency. Simultaneously, it enhances test versatility and flexibility, reduces development costs, and provides detailed evidence for fuse performance optimization, assisting researchers in targeted improvements to materials and structures, thereby enhancing the overall performance and reliability of the fuse. This solves the problems in existing technologies, such as low success rate of fuse overload breaking tests, inaccurate timing of test samples switching from low voltage to full voltage circuit, and large error in test results.

[0031] The following description, with reference to the accompanying drawings, describes a fuse overload breaking method and apparatus according to embodiments of this application.

[0032] Specifically, Figure 1 This is a schematic flowchart of a fuse overload breaking method provided in an embodiment of this application.

[0033] like Figure 1 As shown, the overload breaking method of this fuse includes the following steps:

[0034] In step S101, port voltage data and arc pre-arc time are acquired.

[0035] Among them, port voltage data refers to the voltage value and its changes obtained through a specific measurement point (port) in the fuse test circuit, and arc pre-arc time is the time interval from when the current reaches a certain value (such as the current value at which the fuse element begins to heat up) to when the fuse element melts and generates an arc under fault conditions such as fuse overload or short circuit.

[0036] It is understood that the embodiments of this application obtain the voltage value and changes at the port of the fuse test circuit through specific measurement methods, and record the time interval from when the current reaches a specific value to when the fuse melts and no arc is generated, so as to provide key data support for subsequent analysis of fuse performance and accurate determination of test links.

[0037] In step S102, the critical melting voltage of the fuse is calculated based on the port voltage data and the pre-arc time, combined with the fuse resistance.

[0038] The critical melting voltage refers to the minimum voltage threshold across the port (or contact) of a fuse when the molten element inside the fuse reaches its melting temperature due to the current heating effect and is about to melt under specific test conditions (such as ambient temperature, current waveform, load type, etc.).

[0039] It is understood that the embodiments of this application, by integrating port voltage data and pre-arc time, and linking fuse resistance and temperature parameters to calculate the critical melting voltage of the fuse, can accurately capture the key performance indicators of the fuse under complex operating conditions, effectively improve the scientificity and accuracy of fuse performance evaluation, provide core data support for optimizing fuse design, ensuring the reliability of circuit overload protection, and reducing the risk of electrical faults, and help the electrical system operate safely and stably.

[0040] In this embodiment, based on the port voltage data and the arc pre-arc time, combined with the fuse resistance, the critical melting voltage of the fuse is calculated. The specific formula for the critical melting voltage is as follows:

[0041] ;

[0042] in, For the expected test current, The resistivity of metals at room temperature Where is the melt radius, The length of the melt. For the index, Temperature coefficient of resistance For the arc pre-arc time, It is the specific heat capacity of the melt. The density of the melt. It is the voltage across the two ends of the melt at room temperature.

[0043] Specifically, by connecting a device with voltage monitoring function to the platform to collect data, multiple sets of tests were conducted on the RT28-32“g” type fuse. Voltage data of different specifications under different operating conditions were collected to verify the accuracy of parameters such as the theoretically derived formula for fuse voltage and time and critical melting voltage. The feasibility and reliability of the theoretical design were verified through actual operation. The two are interdependent and work together to serve the research and verification of overload breaking tests of low-voltage fuses.

[0044] In the early stages of the experiment, the sampling rate of the equipment was set uniformly to ensure that the collected data had a strict correspondence in the time dimension, which would facilitate subsequent analysis.

[0045] The relationship between melt resistance R and temperature is as follows:

[0046] ;

[0047] in, Let T be the resistivity of the metal at temperature T. The initial temperature of the melt. The ambient temperature.

[0048] The common formulas for "g" type AC / DC fuses are as follows:

[0049] ;

[0050] The rated current of the fuse. For the expected test current, Set the current for the fuse.

[0051] By Ohm's Law

[0052] U=RI;

[0053] have to

[0054] ;

[0055] The formula for the voltage across the melt is derived through calculation.

[0056] ;

[0057] Therefore, the simplified formula

[0058] ;

[0059] Where t is the change over time.

[0060] Furthermore, during the experimental process, it is necessary to solve for the parameters x and y, as well as And continuously verify its accuracy. It is the voltage across the fuse at room temperature, and it changes with the rated current and rated voltage of the fuse.

[0061] In step S103, test parameters are set for different types of fuses based on the critical melting voltage. The test sample status is checked to see if it meets the low-voltage circuit conditions. If the test sample status meets the low-voltage circuit conditions, the port voltage data is compared and analyzed with the critical melting voltage. When the port voltage data is close to the critical melting voltage and meets the switching conditions, KM1 and KM2 are closed, and KM3 and KM4 are opened, switching the fuse from the low-voltage circuit to the full-voltage test circuit. If the fuse reaches the melting condition in the full-voltage test circuit, it melts rapidly. If the test sample status does not meet the low-voltage circuit conditions, the contactor status is adjusted to the target position for testing.

[0062] The test parameters may include recovery voltage, expected test current and current tolerance. The low-voltage circuit conditions are that contactors KM1 and KM2 are open and KM3 and KM4 are closed. The switching conditions may include that the port voltage is within the preset voltage threshold range corresponding to the fuse specification, the current change rate is within the preset reasonable range, and the arc pre-arc time reaches or is close to the preset arc pre-arc time threshold. The fusing conditions may include electrical parameters, thermal effects and time conditions. The electrical parameters include, but are not limited to, fuse port voltage, current intensity and current change rate; the thermal effects include the fusible element temperature and its heat accumulation.

[0063] It is understood that the embodiments of this application take the critical melting voltage as the core basis, accurately set test parameters such as recovery voltage, expected test current and current tolerance, and determine whether the test sample meets the low-voltage circuit conditions of contactors KM1 and KM2 being open and KM3 and KM4 being closed by carefully checking the state of the test sample. If the low-voltage circuit conditions are met, the port voltage data is further compared with the critical melting voltage. When the switching conditions are met, such as the port voltage being within the preset voltage threshold range corresponding to the fuse specifications, the current change rate being within a reasonable range, and the arc pre-arc time reaching or approaching the preset threshold, KM1 and KM2 are promptly closed, and KM3 and KM4 are opened, smoothly switching the fuse to the full-voltage test circuit. Subsequently, based on electrical parameters including port voltage, current intensity, and current change rate, as well as thermal effect factors such as fuse temperature and heat accumulation, combined with the melting conditions formed by time conditions, it is determined whether the fuse melts rapidly. If the test sample does not meet the low-voltage circuit conditions, the contactor state is flexibly adjusted to the target position for retesting, ensuring the accuracy and standardization of the entire fuse testing process. This not only simulates complex and realistic operating scenarios but also effectively improves testing efficiency and result reliability, providing solid data support and technical assurance for fuse product performance optimization and safe operation of electrical systems.

[0064] Specifically, taking the 500V-10A, 16A, and 32A "g" type fuses as an example, multiple sets of tests were conducted on the RT28-32 "g" type fuses of 10A, 16A, and 32A specifications, as shown in Table 1 below.

[0065]

[0066] This invention utilizes the critical melting voltage As a switching criterion, precise control of fuses of different specifications is achieved. For example... Figure 2 , Figure 3 and Figure 4 As shown, in the 32A fuse test, the switching voltage stabilized at 3.15V when the arc pre-time was 12-25 seconds, and the full-voltage fusing time was 0.18-0.21 seconds; for the 16A fuse, the switching voltage was 1.15V when the arc pre-time was 57-98 seconds, and the full-voltage fusing time was 0.16-0.22 seconds; for the 10A fuse, the switching voltage was 0.60V when the arc pre-time was 121-203 seconds, and the full-voltage fusing time was 0.15-0.19 seconds. The full-voltage fusing time was consistently below 300ms, verifying the scientific validity of the critical melting voltage criterion, the accuracy of the switching device response, and the reliability of the system design.

[0067] In this embodiment of the application, switching the fuse from the low-voltage circuit to the full-voltage test circuit further includes: acquiring the voltage and current changes at the moment of disconnection; and automatically adjusting the absorption parameters based on the voltage and current changes to convert the excess energy generated during the disconnection process into electrical energy and store it in a matching energy storage device, or convert it into heat energy and dissipate it through a heat dissipation component.

[0068] The energy storage equipment can be lithium battery packs, supercapacitors, or lead-acid batteries, etc.

[0069] It is understood that the embodiments of this application achieve intelligent management of excess energy during the breaking process by acquiring the voltage and current changes at the instant of breaking in real time and automatically adjusting the absorption parameters accordingly. On the one hand, excess energy is converted into electrical energy and stored in a matching energy storage device, realizing energy recovery and reuse, improving energy utilization efficiency, and reducing system operating costs. On the other hand, energy is converted into heat energy and dissipated through heat dissipation components, avoiding problems such as overvoltage and overcurrent caused by the accumulation of excess energy, effectively protecting the test equipment and circuit system, enhancing the safety and stability of the fuse testing process, and ensuring the accuracy and reliability of the test results.

[0070] Specifically, in the scenario of fuse testing in a power system, when a fuse switches from a low-voltage circuit to a full-voltage test circuit, an overvoltage of up to several thousand volts and an inrush current of tens of amperes may be generated at the instant of disconnection. At this time, the system rapidly acquires voltage and current change data. If energy storage is chosen, a supercapacitor can be used as the energy storage device. Due to its high power density and rapid charge / discharge characteristics, a supercapacitor can absorb excess electrical energy generated during disconnection within milliseconds. The stored energy can then power auxiliary systems of the test equipment, such as for controlling circuit operation. If heat dissipation is chosen, a high-power resistor can be set in the circuit as an energy-dissipating element. When excess energy is generated at the instant of disconnection, the absorption parameters are automatically adjusted to allow the energy to flow through the high-power resistor, converting electrical energy into heat energy. This heat is then dissipated to the surrounding environment through a heat dissipation assembly consisting of a heat sink and a fan, preventing damage to other components of the test system from overvoltage and overcurrent, and ensuring the safe and stable operation of the entire test process.

[0071] The fuse overload breaking method proposed in this application obtains port voltage data and arc pre-arc time, and calculates the critical melting voltage by combining the resistance-temperature relationship of the fuse element. This allows for precise determination of the switching timing. Customized test parameters are set for different types of fuses, effectively avoiding errors caused by improper switching timing and parameter mismatch, thus improving test accuracy and reliability. Before testing, the sample status is checked; if the low-voltage circuit conditions are not met, the contactor status is adjusted to ensure test safety. After switching to the full-voltage circuit, the fusing conditions are monitored in real time to achieve rapid fusing detection and timely recording of key data. This not only reduces test result errors but also reduces manual intervention through automated operation, shortens the test cycle, and improves test efficiency. Simultaneously, it enhances test versatility and flexibility, reduces development costs, and provides detailed evidence for fuse performance optimization, assisting researchers in targeted improvements to materials and structures, thereby enhancing the overall performance and reliability of fuses. Therefore, it solves the problems of low success rate in fuse overload breaking experiments, inaccurate timing of switching test samples from low-voltage to full-voltage circuits, and large test result errors in existing technologies.

[0072] The following will illustrate the overload breaking method of a fuse through a specific embodiment, such as... Figure 5 As shown, it includes:

[0073] S1: The test sample is connected to the test circuit.

[0074] S2: Preliminary preparation, preheat the low-voltage circuit, collect sample voltage data until it melts under low voltage, keep recording the voltage U and time t under low voltage, and calculate the values ​​of x, y and U0 in the formula.

[0075] Specifically, a voltage monitoring device with high resolution, high sampling frequency and strong anti-interference capability is used to perform real-time and uninterrupted precise monitoring of the voltage across the fuse, collect sample voltage data until the fuse is broken under low voltage, and record the change of the port voltage U-fusing time t under low voltage.

[0076] By connecting a device with voltage monitoring function to the platform to collect data, multiple sets of tests were conducted on the RT28-32“g” type fuse. Voltage data of different specifications under different working conditions were collected to verify the accuracy of the theoretically derived formulas for fuse voltage and time, critical melting voltage, and other parameters. The feasibility and reliability of the theoretical design were verified through actual operation. The two are interdependent and work together to serve the research and verification of overload breaking tests of low-voltage fuses.

[0077] In the early stages of the experiment, the sampling rate of the equipment was set uniformly to ensure that the collected data had a strict correspondence in the time dimension, which would facilitate subsequent analysis.

[0078] The relationship between melt resistance R and temperature is as follows:

[0079] ;

[0080] in, Let T be the resistivity of the metal at temperature T. For ambient temperature

[0081] The common formulas for "g" type AC / DC fuses are as follows:

[0082] ;

[0083] The rated current of the fuse. For the expected test current, Set the current for the fuse.

[0084] By Ohm's Law

[0085] U=RI;

[0086] have to

[0087] ;

[0088] The formula for the voltage across the melt is derived through calculation.

[0089] ;

[0090] Therefore, the simplified formula

[0091] ;

[0092] Where t is the change over time.

[0093] Furthermore, during the experimental process, it is necessary to solve for the parameters x and y, as well as And continuously verify its accuracy. It is the voltage at the fuse port when the current exceeds the test current, and it changes with the rated current and rated voltage of the fuse.

[0094] S3: Combine the voltage across the melt with the arc pre-arc time Combined, the critical melting voltage is determined. .

[0095] S4: Set the test parameters.

[0096] Taking the RT28-32“g” type fuse as an example, the test parameters for different specifications of fuses were determined according to the GB / T13539.1-2015 standard.

[0097] For 10A and 16A fuses, the breaking capacity tests for both DC and AC fuses must clearly define parameters such as recovery voltage, expected test current, and current tolerance. Based on the obtained melting voltage... According to the type of fuse, the test parameter Vtest is precisely set in strict accordance with relevant standards such as GB / T13539.1-2015.

[0098] S5: The testing phase has officially begun, and the new sample has been connected to the test circuit.

[0099] S6: Check the status of the test sample to ensure that the low-voltage circuits KM1 and KM2 are open and KM3 and KM4 are closed in order to proceed with the next test.

[0100] S7: The test sample enters the low-voltage circuit preheating stage.

[0101] S8: Check if the voltage has reached the set test voltage Vtest.

[0102] Specifically, during the test, high-sensitivity voltage monitoring equipment continuously collects voltage data across the fuse terminals, which is then processed by an algorithm and compared with the critical melting voltage formula. The critical melting voltage is used as the core criterion for judgment, combined with factors such as the voltage threshold range, current, and pre-arc time of the corresponding specification for comprehensive evaluation. The voltage across the fuse terminals is continuously monitored. When the voltage approaches the critical melting voltage and the switching conditions are met, the process switches to S9 to switch to the full-voltage circuit; if the switching conditions are not met, it returns to S7 to continue preheating. When the voltage is deemed acceptable, it indicates that the fuse is about to cross the critical threshold between normal operation and the melting state, entering the melting stage. At this point, the control switching device switches the fuse from the low-voltage circuit to the full-voltage circuit, causing the fuse to melt rapidly under high voltage, thus effectively testing the fuse's overload breaking performance.

[0103] S9: Close KM1 and KM2, open KM3 and KM4, and switch to the full-voltage circuit.

[0104] When the voltage across the fuse is detected to be close to its critical melting voltage, the switching unit responds rapidly. Contactors KM1-KM4 operate precisely according to a strict timing sequence and operational logic, with KM1 and KM2 closing and KM3 and KM4 opening. Through this precise operation, the switching unit quickly switches the fuse from the low-voltage circuit to the full-voltage test circuit, ensuring that the fuse can achieve instantaneous and rapid melting under full-voltage conditions when it is nearing its critical melting state, thereby effectively testing the fuse's overload breaking performance.

[0105] S10: Full-voltage fuse and data recording.

[0106] After the fuse is switched to the full-voltage test circuit, the full-voltage circuit module should be able to provide sufficiently high voltage and energy, with a high-voltage fusing time of less than 250ms, rapidly reaching the fusing condition under high-voltage conditions to achieve rapid fusing. The full-voltage circuit module must provide sufficiently high voltage and energy to ensure the fuse blows during the high-voltage phase, ensuring the fuse effectively disconnects the circuit.

[0107] This invention proposes a method based on the critical melting voltage as the core judgment, and designs the control logic and protection mechanism of the test system. When the voltage across the fuse is detected to be close to the critical melting voltage, the fuse is switched from the low-voltage circuit to the full-voltage circuit through a switching device, so that the fuse can achieve instantaneous rapid melting under high voltage. After multiple actual tests, it has been proven that this method can significantly improve the test success rate to 95%, ensuring that the fuse switches back to high voltage for rapid melting in the near melting stage. This not only improves the test efficiency but also reduces the test cost, and has important theoretical and practical value.

[0108] Among them, using the critical melting voltage as the core criterion for judging the switch of a fuse from low voltage to full voltage circuit has a solid theoretical basis, significant technical advantages, and reliable practical verification.

[0109] In overload breaking tests of low-voltage fuses, precise control of the transition timing from low-voltage to full-voltage circuits is crucial. Traditional methods, which set the breaking time t as a threshold, exhibit a negative correlation between the voltage slope k and the threshold voltage. This results in long and highly variable breaking times for the fuse under low overload current conditions, making it impossible to accurately determine the optimal transition moment. Consequently, test results are often inaccurate, inefficient, and costly. This invention uses the critical melting voltage... As a basis for judgment, it can monitor the voltage across the fuse in real time. When the voltage is close, it quickly triggers the switching device to precisely switch the fuse from the low-voltage circuit to the full-voltage test circuit, so that the fuse can achieve instantaneous and rapid melting under high voltage.

[0110] Based on this, the critical melting voltage A switching control method was designed as a key basis for judging the critical state of fuse failure.

[0111] Unlike existing technologies that rely on fixed-time threshold switching methods, which cannot accurately control the timing of the low-voltage to full-voltage circuit under low overload current conditions due to the fuse's breaking characteristics, resulting in large errors and low reliability in test results and seriously affecting power system protection schemes, this invention determines the critical melting voltage by deeply analyzing the important parameters of the fuse during the melting process. As a reliable and effective test criterion, a corresponding switching control method was designed. Multiple practical tests have proven that this method can significantly improve the test success rate to 95%, ensuring that the fuse rapidly melts when switched back to high voltage near the melting point. This not only improves test efficiency but also reduces test costs. Theoretically, this invention establishes the critical melting voltage as a reliable switching criterion, greatly improving test accuracy and enabling accurate evaluation of the actual performance of the fuse, thus enhancing the scientific nature of power system protection schemes. In terms of hardware design, the modules work closely together to achieve accurate simulation of the full-voltage circuit, reliable switching of the switching device, and stable current supply from the low-voltage constant current source, improving system stability and reducing failure rate and maintenance costs. Regarding experimental methods, the entire process has been optimized, from initialization and parameter setting to monitoring, switching, and data analysis, improving test efficiency, reducing resource consumption, and accelerating fuse research and development and quality improvement. It has significant theoretical and practical value, providing strong support for the development of power system protection technology and the improvement of fuse product quality.

[0112] Next, referring to the accompanying drawings, an overload breaking device for a fuse according to an embodiment of this application is described.

[0113] Figure 6 This is a block diagram of a fuse overload breaking device according to an embodiment of this application.

[0114] like Figure 6 As shown, the fuse overload breaking device 10 includes: an acquisition module 100, a calculation module 200, and a fuse breaking module 300.

[0115] The acquisition module 100 is used to acquire port voltage data and arc pre-arc time; the calculation module 200 is used to calculate the critical melting voltage of the fuse based on the port voltage data and arc pre-arc time, combined with the fuse resistance; the fusing module 300 is used to set test parameters for different types of fuses based on the critical melting voltage, check whether the test sample status meets the low-voltage circuit conditions, if the test sample status meets the low-voltage circuit conditions, compare and analyze the port voltage data with the critical melting voltage, when the port voltage data is close to the critical melting voltage and meets the switching conditions, close KM1 and KM2, open KM3 and KM4, and switch the fuse from the low-voltage circuit to the full-voltage test circuit. If the fuse reaches the fusing condition in the full-voltage test circuit, it will fuse rapidly; if the test sample status does not meet the low-voltage circuit conditions, adjust the contactor status to the target position for testing.

[0116] In this embodiment, it also includes: a full-voltage circuit module, a conversion device unit, and a low-voltage constant current source submodule.

[0117] The full-voltage circuit module consists of a full-voltage side circuit breaker, an adjustable transformer, a rectifier cabinet, an adjustable load reactor, an adjustable load resistor, and a full-voltage side contactor group. The conversion unit includes four contactors: KM1 and KM2 control the on / off of the full-voltage side circuit, and KM3 and KM4 control the low-voltage constant current source side circuit. The low-voltage constant current source submodule is used to provide a stable current to the fuse, so that the fuse operates in a low-voltage, safe environment in the initial stage of the test, avoiding premature melting caused by high-voltage impact, and ensuring stable and repeatable testing.

[0118] It is understood that the embodiments of this application, through the collaborative design of a full-voltage circuit module, a conversion device unit, and a low-voltage constant current source submodule, integrate various electrical devices. The full-voltage circuit module can flexibly adjust parameters such as voltage and current required for testing, simulating real and complex full-voltage operating conditions. The conversion device unit uses four contactors to precisely control the circuit's on / off state, achieving safe switching between the full-voltage side and the low-voltage constant current source side. The low-voltage constant current source submodule provides a stable low-voltage current in the initial stage of the test, preventing the fuse from prematurely blowing due to high-voltage impact, ensuring the safety, stability, and repeatability of the testing process. The three components work together to not only improve the accuracy and reliability of fuse testing but also comprehensively and realistically evaluate fuse performance, providing a solid guarantee for the research, development, production, and quality inspection of electrical equipment, and effectively reducing the risk of electrical faults caused by poor fuse performance.

[0119] It should be noted that the foregoing explanation of the fuse overload breaking method embodiment also applies to the fuse overload breaking device of this embodiment, and will not be repeated here.

[0120] The fuse overload breaking device proposed in this application calculates the critical melting voltage by acquiring port voltage data and arc pre-arc time, combined with the fuse resistance-temperature relationship, to accurately determine the switching timing. Customized test parameters are set for different types of fuses, effectively avoiding errors caused by improper switching timing and parameter mismatch, thus improving test accuracy and reliability. Before testing, the sample condition is checked; if the low-voltage circuit conditions are not met, the contactor condition is adjusted to ensure test safety. After switching to the full-voltage circuit, the fusing condition is monitored in real time, enabling rapid fusing detection and timely recording of key data. This not only reduces test result errors but also reduces manual intervention through automated operation, shortening the test cycle and improving test efficiency. Simultaneously, it enhances test versatility and flexibility, reduces development costs, and provides detailed evidence for fuse performance optimization, assisting researchers in targeted improvements to materials and structures, thereby enhancing the overall performance and reliability of the fuse. Therefore, it solves the problems of low success rate in fuse overload breaking experiments, inaccurate timing of switching from low-voltage to full-voltage circuits, and large test result errors in existing technologies.

[0121] The following is a detailed description of a fuse overload breaking device through a specific embodiment:

[0122] like Figure 7 As shown, the full-voltage circuit module, conversion unit, low-voltage constant current source subsystem, and monitoring module work together.

[0123] Full-voltage circuit module: The full-voltage circuit module consists of a full-voltage side circuit breaker QF0, an adjustable transformer T, a rectifier cabinet TB, an adjustable load reactor L, an adjustable load resistor R, and a full-voltage side contactor group. QF0 controls the circuit to open and close and protects the circuit; T adjusts the voltage amplitude to meet test requirements; TB converts AC to DC; L and R work together to regulate the load characteristics.

[0124] Switching Unit: The switching unit contains four contactors responsible for the precise switching of the fuse between the low-voltage and full-voltage circuits. Among them, KM1 and KM2 control the on / off of the full-voltage side circuit, while KM3 and KM4 control the low-voltage constant current source side circuit, ensuring rapid and precise circuit switching when the fuse approaches the critical melting point.

[0125] Low-voltage constant current source submodule: The low-voltage constant current source submodule provides a stable current to the fuse, enabling the fuse to operate in a low-voltage, safe environment during the initial stage of the test, avoiding premature melting caused by high-voltage surges, and ensuring stable and repeatable testing.

[0126] Monitoring and Control Module: The monitoring and control module is equipped with a voltage sensor V, a Hall effect current transformer A, and a specific voltage monitoring device. V and A monitor voltage and current signals respectively, while the voltage monitoring device monitors the voltage across the fuse in real time and accurately. The monitored voltage is compared with the critical melting voltage in real time. When the voltage approaches the critical value, the switching device unit is triggered, controlling the fuse to switch from the low-voltage circuit to the full-voltage test circuit.

[0127] In summary, the embodiments of this application construct a system including a full-voltage circuit to provide a high-voltage environment that meets the test requirements, ensuring reliable conduction and disconnection of the full-voltage side circuit; a switching device to achieve precise switching of the fuse between the low-voltage and full-voltage circuits; a low-voltage constant current source system to provide a stable low current to the fuse, enabling the fuse to operate in a low-current, safe environment at the beginning of the test; and other auxiliary hardware to monitor the real-time voltage and current of the fuse. In multiple field tests, this system demonstrated excellent performance, not only improving the test success rate and ensuring the fuse rapidly melts back to high voltage near the melting point, but also improving test efficiency and reducing test costs. It possesses significant economic benefits and practical value, promoting the development of related research and applications.

[0128] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0129] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0130] Any process or method described in the flowchart or otherwise herein can be understood as representing a module, segment, or portion of code comprising one or N executable instructions for implementing custom logic functions or processes, and the scope of the preferred embodiments of this application includes additional implementations in which functions may be performed not in the order shown or discussed, including substantially simultaneously or in reverse order depending on the functions involved, as should be understood by those skilled in the art to which embodiments of this application pertain.

[0131] It should be understood that the various parts of this application can be implemented using hardware, software, firmware, or a combination thereof. In the above embodiments, the N steps or methods can be implemented using 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 more 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.

[0132] Those skilled in the art will understand that all or part of the steps of the methods described 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, it includes one or a combination of the steps of the method embodiments.

Claims

1. A method of overload interruption by a fuse, characterized by, The method comprises the following steps: acquiring port voltage data and arc-before time; calculating critical melting voltage of the fuse based on the port voltage data and the arc-before time in combination with the melt resistance, wherein the specific formula of the critical melting voltage is: ； wherein, is the expected test current, is the room temperature metal resistivity, is the melt radius, is the melt length, e is the exponential, is the temperature coefficient of resistance, is the pre-arc time, is the specific heat capacity of the melt, is the density of the melt, is the pre-arc time, is the two-terminal voltage at room temperature of the melt; setting test parameters for different types of fuses based on the critical melting voltage, checking whether the test sample state meets the low-voltage loop condition, wherein the test parameters include recovery voltage, expected test current and current tolerance, the low-voltage loop condition is that contactors KM1 and KM2 are disconnected, and KM3 and KM4 are closed, if the test sample state meets the low-voltage loop condition, the port voltage data is compared and analyzed with the critical melting voltage, when the port voltage data approaches the critical melting voltage and meets the switching condition, wherein the switching condition includes that the port voltage is within the preset voltage threshold range corresponding to the fuse specification, the current rate of change is within the preset reasonable range, and the arc-before time reaches or approaches the preset arc-before time threshold, KM1 and KM2 are closed, and KM3 and KM4 are disconnected, and the fuse is switched from the low-voltage loop to the full-voltage test loop, wherein switching the fuse from the low-voltage loop to the full-voltage test loop further comprises: acquiring voltage and current changes at the breaking moment; based on the voltage and current changes, automatically adjusting the absorption parameters, converting the excess energy generated in the breaking process into electrical energy and storing it in the matching energy storage device, or converting it into heat energy and dissipating it through the heat dissipation assembly; if the fuse reaches the fuse condition in the full-voltage test loop, it is rapidly fused; if the test sample state does not meet the low-voltage loop condition, adjust the contactor state to the target position for testing.

2. The fuse overload interruption method of claim 1, wherein, The fuse condition includes electrical parameters, thermal effects, and time conditions, wherein the electrical parameters include but are not limited to fuse port voltage, current intensity, and current rate of change; the thermal effects include melt temperature and thermal accumulation.

3. A fuse overload interrupting device characterized by, comprises: an acquisition module for acquiring port voltage data and arc-before time; a calculation module for calculating critical melting voltage of the fuse based on the port voltage data and the arc-before time in combination with the melt resistance, wherein the specific formula of the critical melting voltage is: ； wherein, is the expected test current, is the room temperature metal resistivity, is the melt radius, is the melt length, e is an exponent, is the temperature coefficient of resistance, is the pre-arc time, is the specific heat capacity of the melt, is the density of the melt, is the pre-arc time, is the two-terminal voltage at room temperature of the melt; The fuse module is used to set test parameters for different types of fuses based on the critical melting voltage, and check whether the test sample state meets the low-voltage loop condition, wherein the test parameters include recovery voltage, expected test current and current tolerance, the low-voltage loop condition is that the contactors KM1 and KM2 are disconnected, and KM3 and KM4 are closed, if the test sample state meets the low-voltage loop condition, the port voltage data is compared with the critical melting voltage, when the port voltage data approaches the critical melting voltage and meets the switching condition, wherein the switching condition includes that the port voltage is in the preset voltage threshold range corresponding to the fuse specification, the current change rate is in the preset reasonable range, and the pre-arcing time reaches or approaches the preset pre-arcing time threshold, KM1 and KM2 are closed, and KM3 and KM4 are disconnected, and the fuse is switched from the low-voltage loop to the full-voltage test loop, wherein switching the fuse from the low-voltage loop to the full-voltage test loop further comprises: obtaining voltage and current changes at the breaking moment; based on the voltage and current changes, automatically adjusting the absorption parameters, converting the excess energy generated in the breaking process into electrical energy and storing it in the matching energy storage device, or converting it into heat energy and dissipating it through the heat dissipation assembly; if the fuse reaches the melting condition in the full-voltage test loop, it will melt rapidly; if the test sample state does not meet the low-voltage loop condition, adjust the contactor state to the target position for testing.

4. The fuse overload interrupt device of claim 3, wherein, Also includes: Full-voltage circuit module, conversion device unit and low-voltage constant current source submodule, wherein The full-voltage circuit module is composed of a full-voltage side circuit breaker, an adjustable transformer, a rectifier cabinet, an adjustable load reactor, an adjustable load resistor and a full-voltage side contactor group; The conversion device unit includes four contactors, KM1 and KM2 control the on-off of the full-voltage side circuit, and KM3 and KM4 control the low-voltage constant current source side circuit; The low-voltage constant current source submodule is used to provide stable current for the fuse, so that the fuse operates in a low-voltage and safe environment in the initial stage of the test, avoids premature melting caused by high-voltage impact, and ensures stable and repeatable testing.

Images