Method and device for predicting asymmetric short-circuit current breaking result of high-voltage SF6 circuit breaker and medium

Abstract

The invention relates to a high-voltage SF6 circuit breaker asymmetric short-circuit current breaking result prediction method, equipment and a medium. The method comprises the following steps: acquiring a plurality of groups of arc voltage and arc current test data obtained by performing a T100a test on a target circuit breaker under a first time constant; based on the test data, establishing a black box arc model, and fitting to obtain arc dissipation power and arc time constant corresponding to each group of test data through numerical solution and parameter optimization algorithms, thereby obtaining an on-off critical value; fitting is carried out in an arc breaking critical parameter fitting model, and values of a first parameter, a second parameter, a third parameter and a fourth parameter are determined; and obtaining a predicted value of an on-off value under the working condition through an arc on-off critical parameter fitting model, if the predicted value is greater than an on-off critical value, determining that on-off is successful, otherwise, determining that on-off is failed. Compared with the prior art, the method has the advantages of high accuracy, high practicability, simple process and the like.

Description

Technical Field

[0001] This invention relates to the field of high-voltage circuit breaker technology, and in particular to a method, device and medium for predicting the breaking results of asymmetrical short-circuit current in a high-voltage SF6 circuit breaker. Background Technology

[0002] With the continuous improvement of power system voltage levels and capacity, as well as the large-scale integration of high-voltage direct current transmission and new energy power generation, the level of short-circuit current in the power grid continues to increase. To limit the amplitude of short-circuit current, high-impedance transformers and current-limiting reactors are widely used in the system, resulting in a significant increase in the decay time constant of the DC component in the short-circuit current. The occurrence of asymmetrical short-circuit current and the extension of its time constant greatly increase the difficulty and complexity of circuit breaker interruption.

[0003] Currently, domestic and international research on the impact of the DC component of short-circuit current on circuit breaker breaking performance largely treats the breaking capacity of circuit breakers as a fixed parameter at the system level, lacking precise modeling and effective evaluation methods for the breaking process of asymmetric short-circuit currents. In circuit breaker breaking tests and simulation studies, the breaking nature of SF6 circuit breakers involves the dynamic evolution of gas arcs. Therefore, researchers have proposed various arc mathematical models, such as the Cassie model, Mayr model, and TP KEMA model—black-box models—which use differential equations to describe the changes in arc conductance to simulate the breaking process. While these models can reflect arc characteristics to some extent, they still have significant limitations.

[0004] In particular, some existing technologies employ simplified enthalpy-current models combined with black-box arc models for asymmetric breaking simulations, which suffer from insufficient accuracy in simulating arc voltage and current waveforms, making it difficult to realistically reproduce the arc behavior of circuit breakers during actual breaking processes. Furthermore, some black-box models have numerous parameters and high optimization dimensionality, leading to difficulties in parameter identification and impacting stability and prediction accuracy.

[0005] Chinese patent application CN112528586A discloses a method, medium, and system for evaluating the breaking performance of high-voltage circuit breakers. It employs a KEMA black-box arc model combined with modern optimization algorithms to extract parameters from the arc black-box model, establishing a circuit simulation model to simulate asymmetric short-circuit currents. The simulation generates arc current waveforms, and the asymmetric short-circuit current breaking capacity of the high-voltage circuit breaker is evaluated based on these waveforms. However, the simplified enthalpy-current model in this application simulates arc voltage and current waveforms with low accuracy, resulting in incomplete simulation of the circuit breaker's breaking operation and significantly impacting subsequent simulation errors. Furthermore, the KEMA black-box arc model has six arc parameters, and the global optimization results vary considerably in six-dimensional space, making parameter extraction difficult and affecting the accuracy of model predictions. Therefore, finding an accurate and reliable method to evaluate the breaking performance of high-voltage SF6 circuit breakers under asymmetric short-circuit current conditions, meeting the practical needs of power systems for precise evaluation of circuit breaker breaking capacity, and improving the stability and safety of power systems are technical problems that need to be solved. Summary of the Invention

[0006] The purpose of this invention is to overcome the defects of the existing technology and provide a method, device and medium for predicting the asymmetric short-circuit current interruption result of high-voltage SF6 circuit breakers. By accurately fitting the black box arc model, key parameters such as arc dissipation power and time constant are obtained. By introducing an arc interruption critical parameter fitting model that comprehensively considers the contact opening distance and the chamber gas pressure, the accurate prediction of the asymmetric short-circuit current interruption result can be achieved.

[0007] The objective of this invention can be achieved through the following technical solutions:

[0008] According to one aspect of the present invention, a method for predicting the breaking result of asymmetric short-circuit current of a high-voltage SF6 circuit breaker is provided, the specific steps of which include: S1, collecting several sets of arc voltage and arc current test data obtained by the target circuit breaker under a T100a test at a first time constant; S2, based on the test data, establishing a black box arc model, and fitting the arc dissipation power and arc time constant corresponding to each set of test data through numerical solution and parameter optimization algorithm, thereby obtaining the breaking critical value; S3, obtaining the contact opening distance and the main chamber gas pressure in the arc extinguishing chamber corresponding to each set of test data, and inputting them into the arc breaking critical parameter fitting model for fitting, and determining the values ​​of the first parameter, the second parameter, the third parameter, and the fourth parameter; S4, for the operating condition to be predicted, obtaining the second time constant and the arcing time, as well as the contact opening distance and the main chamber gas pressure in the arc extinguishing chamber under the operating condition; obtaining the predicted value of the breaking value under the operating condition through the arc breaking critical parameter fitting model, if the predicted value is greater than the breaking critical value, it is determined that the breaking is successful, otherwise it is determined that the breaking is unsuccessful.

[0009] Furthermore, the equation expression for the black-box arc model in S2 is as follows:

[0010]

[0011] Where g is the total arc conductance, u is the calculated arc voltage, t is time, T is the arc time constant, P is the arc dissipation power, and i is the arc current. The total arc conductance g and the calculated arc voltage u are unknowns to be solved.

[0012] Furthermore, the black box arc model is solved using the Runge-Kutta method.

[0013] Furthermore, after obtaining the total arc conductance g and the calculated arc voltage u, the error between the arc voltage test data and the calculated arc voltage is calculated; the error is used as the objective function, and the arc time constant and arc dissipation power that minimize the error are obtained through the particle swarm optimization algorithm, which are used as the critical parameters for breaking.

[0014] Furthermore, the breaking critical value is obtained from the breaking critical parameter, and its value is the product of the arc voltage change rate and the arc current change rate calculated from the breaking critical parameter, expressed as:

[0015]

[0016] Where K is the critical value for breaking, P′ is the optimized arc dissipation power, and T′ is the optimized arc time constant.

[0017] Furthermore, the arc breaking critical parameter fitting model includes an arc column segment model between arc contacts, a gas blowing arc cooling model, and a comprehensive influencing factor model. In the arc column segment model between arc contacts, the longer the contact distance, the longer the arc contact distance, the greater the chamber gas pressure, the better the arc cooling effect, the greater the arc resistance, and the higher the arc voltage extinguishing peak value, thus the greater the product of the arc voltage change rate and the arc current change rate. In the gas blowing arc cooling model, the arc elongation is caused by gas blowing arc cooling, while the gas flow is determined by the chamber gas pressure, i.e., the influence of chamber gas pressure on the product of the arc voltage change rate and the arc current change rate. The comprehensive influencing factor model includes the influence of other comprehensive influencing factors, besides the arc column segment between arc contacts and the gas blowing arc cooling model, on the product of the arc voltage change rate and the arc current change rate.

[0018] Furthermore, the expression for the arc breaking critical parameter fitting model is as follows:

[0019]

[0020] Where P is the optimized arc dissipation power, T is the optimized arc time constant, k1, k2, k3 and β are the first parameter, the second parameter, the third parameter and the fourth parameter, respectively, l is the contact opening distance corresponding to the breaking critical parameter, and p is the gas pressure of the main chamber in the arc extinguishing chamber corresponding to the breaking critical parameter.

[0021] Furthermore, the time constants of the test data in S1 are the same, but the arcing times are different.

[0022] According to a second aspect of the present invention, an electronic device is provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the program to implement the method described thereon.

[0023] According to a third aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, which, when executed by a processor, implements the method described thereon.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) Constructing a fitting model for critical parameters of arc breaking to improve prediction accuracy: A structured fitting model for critical parameters of arc breaking was established. The expression directly characterizes the energy dissipation characteristics of the arc column segment between the arc contacts, clearly reflects the synergistic enhancement effect of the square of the contact gap and the power of the chamber pressure on the arc resistance and the peak voltage of the arc extinguishing. Considering the arc elongation effect caused by gas blowing and cooling, the key influence of pressure on driving airflow and enhancing cooling to improve breaking capacity is highlighted. In addition, the comprehensive compensation term covers other influencing factors that are not clearly modeled but actually exist, ensuring the completeness of the model. The fitting model for critical parameters of arc breaking enables the model to simultaneously and quantitatively capture the combined influence of the two key arc extinguishing chamber state parameters, contact gap and gas pressure, on the critical parameters of breaking. This overcomes the limitations of traditional methods that rely solely on current and voltage waveforms or single physical quantities for prediction, and improves the accuracy of breaking result prediction under different structural parameters and operating conditions.

[0026] (2) Significantly improves the reliability and practicality of breaking performance prediction: By establishing a black box arc model and based on real T100a test data, the key parameters such as arc dissipation power and time constant are accurately fitted by numerical solution and parameter optimization algorithm. This effectively overcomes the simulation error caused by the simplification of the model and the difficulty in parameter identification in the prior art. By introducing an arc breaking critical parameter fitting model that comprehensively considers the contact opening distance and the chamber gas pressure, it can more realistically reflect the physical characteristics of the arc and the working state of the arc extinguishing chamber, thereby achieving accurate prediction of the breaking result of asymmetric short circuit current. This avoids the cumbersome process of establishing a complex circuit simulation model and making indirect judgments based on the simulation current waveform in the prior art, greatly simplifies the evaluation process, reduces the computational complexity and dependence on professional simulation software, and makes it easier for engineering technicians to apply and promote in actual research and development and testing.

[0027] (3) A complete, efficient and easy-to-use systematic solution has been formed: This invention only requires one test data of T100a with a specific time constant to calibrate the model. After that, for new time constants or arcing time conditions, it is only necessary to obtain the contact opening distance and gas pressure through physical simulation and substitute them into the calibrated empirical formula to quickly predict the breaking result. There is no need to repeat the complex circuit simulation or arc modeling, which greatly simplifies the prediction process and improves the evaluation efficiency. Attached Figure Description

[0028] Figure 1 Flowchart of the method for predicting the interruption results of asymmetrical short-circuit current of high-voltage SF6 circuit breakers;

[0029] Figure 2 This is a schematic diagram of the physical simulation geometric model. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0031] Example 1

[0032] like Figure 1 As shown, a method for predicting the breaking result of asymmetrical short-circuit current in a high-voltage SF6 circuit breaker includes the following specific steps:

[0033] S1. Collect several sets of arc voltage and arc current test data obtained from the T100a test of the target circuit breaker under the first time constant; S2. Based on the test data, establish a black box arc model, and obtain the arc dissipation power and arc time constant corresponding to each set of test data through numerical solution and parameter optimization algorithm, and then obtain the breaking critical value; S3. Obtain the contact opening distance and the main chamber gas pressure in the arc extinguishing chamber corresponding to each set of test data, and input them into the arc breaking critical parameter fitting model for fitting, and determine the values ​​of the first parameter, the second parameter, the third parameter and the fourth parameter; S4. For the predicted working condition, obtain the second time constant and arcing time, as well as the contact opening distance and the main chamber gas pressure in the arc extinguishing chamber under the working condition; obtain the predicted value of the breaking value under the working condition through the arc breaking critical parameter fitting model. If the predicted value is greater than the breaking critical value, it is determined that the breaking is successful; otherwise, it is determined that the breaking is unsuccessful.

[0034] In S1, the target circuit breaker to be predicted has undergone a T100a test under the first time constant, thereby obtaining at least four sets of test data on arc voltage and arc current with the same time constant but different arcing times. Circuit breakers are generally subjected to a T100a type test at the factory.

[0035] The equation expression for the black-box arc model in S2 is:

[0036]

[0037] Where g is the total arc conductance, u is the calculated arc voltage, t is time, T is the arc time constant, P is the arc dissipation power, and i is the arc current. The total arc conductance g and the calculated arc voltage u are unknowns to be solved. The parameters required for optimal fitting are the arc dissipation power P and the arc time constant T.

[0038] The black-box arc model is solved using the Runge-Kutta method. Based on the arc conductance, arc current, and arc voltage at the current sampling point, the arc conductance and arc voltage at each subsequent sampling point are calculated progressively. The discrete form expression of the black-box arc model obtained using the Runge-Kutta method is as follows:

[0039]

[0040] in, This is the functional form of the equations for the black-box arc model. Let h be the arc conductance, and h be the current time t. n Arc conductance state The time interval used to advance to the next moment. and The first, second, third, and fourth intermediate slopes are used to estimate the average rate of change of arc conductance within one step.

[0041] Through iterative calculations, based on the black-box model differential equations, experimental current data, and a set of candidate arc parameters, the corresponding arc voltage waveform is simulated and calculated. Then, the arc parameters are continuously adjusted using an optimization algorithm to ultimately find the optimal set of parameters that best reproduces the actual experimental data. After obtaining the total arc conductance g and the calculated arc voltage u, the error between the experimental arc voltage data and the calculated arc voltage is calculated. Using this error as the objective function, a particle swarm optimization algorithm is used to obtain the arc time constant and arc dissipation power that minimize the error, which are then used as the critical parameters for interruption.

[0042] The breaking critical value is obtained from the breaking critical parameter, and its value is the product of the rate of change of arc voltage and the rate of change of arc current calculated from the breaking critical parameter. The expression is:

[0043]

[0044] Where K is the critical value for breaking, P′ is the optimized arc dissipation power, and T′ is the optimized arc time constant.

[0045] Multiphysics simulation software was used to model the physical arc of the target circuit breaker. Parameters were set based on actual test conditions to obtain the contact opening distance and the gas pressure in the main chamber of the arc-extinguishing chamber for each test group. The purpose of physical modeling was to simulate and obtain the corresponding contact opening distance and gas pressure in the arc-extinguishing chamber for each group. For self-energized circuit breakers, the change in pressure in the thermal expansion chamber has a more significant impact on the circuit breaker's breaking performance; therefore, the gas pressure in the main chamber can be the pressure in the thermal expansion chamber at the moment of circuit breaker breaking. For compressed air circuit breakers, the change in pressure in the compressed air chamber has a more significant impact on the circuit breaker's breaking performance; therefore, the gas pressure in the main chamber can be the pressure in the compressed air chamber at the moment of circuit breaker breaking.

[0046] The fitting model for the critical parameters of arc breaking includes the arc column segment model between the arc contacts, the gas blowing and cooling model, and the comprehensive influencing factor model. In the arc column segment model between the arc contacts, the longer the contact distance, the longer the arc contact distance, the greater the chamber gas pressure, the better the arc cooling effect, the greater the arc resistance, and the higher the peak value of the arc voltage extinguishing, the greater the product of the arc voltage change rate and the arc current change rate. In the gas blowing and cooling model, the arc elongation is caused by gas blowing and cooling, while the gas flow is determined by the chamber gas pressure, i.e., the influence of the chamber gas pressure on the product of the arc voltage change rate and the arc current change rate. The comprehensive influencing factor model includes the influence of other comprehensive influencing factors, excluding the arc column segment between the arc contacts and the gas blowing and cooling model, on the product of the arc voltage change rate and the arc current change rate.

[0047] The expression for the fitting model of the critical parameters for arc breaking is:

[0048]

[0049] Where P is the optimized arc dissipation power, T is the optimized arc time constant, k1, k2, k3 and β are the first parameter, the second parameter, the third parameter and the fourth parameter, respectively, l is the contact opening distance corresponding to the breaking critical parameter, and p is the gas pressure of the main chamber in the arc extinguishing chamber corresponding to the breaking critical parameter.

[0050] The arc breaking critical parameter fitting model covers various arc conditions under different contact opening distances and gas pressures. It is obtained through in-depth analysis and fitting of these rich data, making the formula highly reliable and applicable. It can effectively describe and reflect the relationship between arc-related parameters, providing support and assistance for the theoretical research and engineering practice of circuit breaker breaking.

[0051] This embodiment uses real experimental data to calculate the critical value for breaking the circuit as the basis for judgment, which is more accurate than the current and voltage data obtained from simulation, making the judgment more convincing. The calculated value of the product of the arc voltage change rate and the arc current change rate under the condition to be predicted is compared with the critical value to predict the breaking result. There is no need to build a complicated circuit simulation model to judge based on the current waveform, which simplifies the evaluation process and improves engineering practicality.

[0052] With the development of ultra-high voltage (UHV) power transmission technology and the increasing proportion of new energy power generation (such as wind and solar power) in the power grid, the characteristics of short-circuit currents in power systems have become more complex and diverse, and asymmetrical short-circuit currents are occurring more frequently. This invention utilizes physical simulation to obtain key parameters such as contact gap and main chamber pressure, and combines this with formulas for deviation correction. This provides accurate data support for the research and development of UHV SF6 circuit breakers and new circuit breakers suitable for new energy grid integration. By accurately predicting breaking results, key components of the circuit breaker, such as the arc-extinguishing chamber structure and contact materials, can be improved in a targeted manner, enhancing the breaking performance of the circuit breaker under complex operating conditions and ensuring the safe and stable operation of UHV power transmission systems and new energy grid integration.

[0053] In the field of power system short-circuit fault analysis, the interruption result prediction method provided in this embodiment can significantly improve the accuracy of assessing the power system's fault response capability. By accurately predicting the interruption result of high-voltage SF6 circuit breakers under asymmetrical short-circuit current, the stability changes of the system under fault conditions can be predicted in advance. When the circuit breaker effectively interrupts the fault, it can prevent the fault from spreading and maintain the stable operation of the power grid; and if a situation where ineffective interruption is predicted, the system operation mode can be adjusted in time or other protective measures can be taken in advance, effectively reducing the impact of short-circuit faults on the entire power system, reducing the scope and duration of power outages, and improving the reliability and security of the power grid.

[0054] This embodiment offers significant guidance for the selection and optimization of power equipment. By using real experimental data to calculate the breaking critical value of the product of the arc voltage change rate and the arc current change rate as a judgment criterion, the selection of high-voltage SF6 circuit breakers can be more accurately based on the short-circuit current characteristics of the actual power system. This avoids the use of circuit breakers based on simulation data that may have inaccuracies, leading to ineffective short-circuit current interruption in actual operation, causing equipment damage or even more serious accidents. Furthermore, based on accurate prediction results, the performance parameters of the circuit breakers can be optimized, improving their breaking capacity in the face of asymmetrical short-circuit currents, extending equipment lifespan, and reducing the replacement costs of power system equipment.

[0055] Example 2

[0056] This embodiment uses a 40.5kV self-energized high-voltage SF6 circuit breaker as an example to evaluate it using this evaluation method. The target circuit breaker has undergone a T100a test with a time constant of 75ms, and five sets of test data on arc voltage and arc current with the same time constant but different arcing times have been obtained. The test results are shown in Table 1.

[0057] Table 1. Experimental Results

[0058]

[0059] The calculation results of the arc parameters are shown in Table 2. Therefore, the critical value of breaking K is taken as 1.65.

[0060] Table 2 Calculation results of arc parameters

[0061]

[0062] Multiphysics simulation software was used to perform physical arc simulation modeling on the target circuit breaker. The geometric model was simplified based on the complex structure of the target circuit breaker, such as... Figure 2 As shown, considering the connection relationship between each gas chamber and setting parameters according to the actual test conditions, the contact opening distance and the gas pressure of the main chamber in the arc extinguishing chamber corresponding to each test group are obtained. The physical simulation data of the test group are shown in Table 3.

[0063] Table 3 Physical simulation results

[0064]

[0065]

[0066] The final values ​​obtained are: k1 = -1.3424E+15; k2 = 2.9659E+18; k3 = -8.4311E+16; b = -1.9000. For self-energized circuit breakers, the change in pressure in the thermal expansion chamber has a more significant impact on the circuit breaker's breaking performance; therefore, the main chamber gas pressure can be the pressure of the thermal expansion chamber at the moment the circuit breaker breaks. For compressed air circuit breakers, the change in pressure in the compressed air chamber has a more significant impact on the circuit breaker's breaking performance; therefore, the main chamber gas pressure can be the pressure of the compressed air chamber at the moment the circuit breaker breaks.

[0067] Physical simulation was used to determine the circuit breaker under the predicted conditions (e.g., a 120ms time constant and 4 arcing times t). arc By substituting the contact gap and the gas in the main chamber (below) into the fitted formula, the product of the arc voltage change rate and the arc current change rate can be calculated.

[0068] The calculated product of the arc voltage change rate and the arc current change rate under the conditions to be predicted is compared with the critical value K to predict the breaking result. If it is less than the critical value K, the breaking fails; if it is greater than the critical value K, the breaking succeeds. The physical simulation calculation results and prediction results under the conditions to be predicted are shown in Table 4.

[0069] Table 4 Simulation Calculation and Prediction Results

[0070]

[0071] Subsequent experiments were conducted under the conditions to be predicted, and the results were compared and verified with the prediction results. The prediction accuracy reached 100%, indicating that the evaluation method proposed in this patent is accurate and feasible.

[0072] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the described module can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0073] The electronic device of this invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in read-only memory (ROM) or loaded from a storage unit into random access memory (RAM). The RAM may also store various programs and data required for device operation. The CPU, ROM, and RAM are interconnected via a bus. Input / output (I / O) interfaces are also connected to the bus.

[0074] Multiple components in the device are connected to an I / O interface, including: input units such as a keyboard, mouse, etc.; output units such as various types of displays, speakers, etc.; storage units such as disks, optical disks, etc.; and communication units such as network interface cards, modems, wireless transceivers, etc. The communication unit allows the device to exchange information / data with other devices through computer networks such as the Internet and / or various telecommunications networks. The processing unit performs the various methods and processes described above, such as the method of the present invention. For example, in some embodiments, the method of the present invention may be implemented as a computer software program tangibly contained in a machine-readable medium, such as a storage unit. In some embodiments, part or all of the computer program may be loaded and / or installed on the device via ROM and / or the communication unit. When the computer program is loaded into RAM and executed by the CPU, one or more steps of the method of the present invention described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute the method of the present invention by any other suitable means (e.g., by means of firmware).

[0075] The functions described above in this document can be performed, at least in part, by one or more hardware logic components. For example, exemplary types of hardware logic components that can be used, without limitation, include: Field Programmable Gate Arrays (FPGAs), Application-Specific Integrated Circuits (ASICs), Application Standard Products (ASSPs), System-on-Chip (SoCs), Complex Programmable Logic Devices (CPLDs), and so on.

[0076] The program code used to implement the methods of the present invention can be written in any combination of one or more programming languages. This program code can be provided to a processor or controller of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that when executed by the processor or controller, the program code causes the functions / operations specified in the flowcharts and / or block diagrams to be implemented. The program code can be executed entirely on the machine, partially on the machine, as a standalone software package partially on the machine and partially on a remote machine, or entirely on a remote machine or server.

[0077] In the context of this invention, a machine-readable medium can be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, apparatus, or device. A machine-readable medium can be a machine-readable signal medium or a machine-readable storage medium. Machine-readable media can include, but are not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, apparatus, or devices, or any suitable combination of the foregoing. More specific examples of machine-readable storage media include electrical connections based on one or more wires, portable computer disks, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), optical fibers, portable compact disk read-only memory (CD-ROM), optical storage devices, magnetic storage devices, or any suitable combination of the foregoing.

[0078] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A method for predicting the asymmetric short-circuit current breaking result of a high-voltage SF6 circuit breaker, characterized in that, The specific steps include: S1, collecting a plurality of sets of arc voltage and arc current test data obtained by a target circuit breaker in a T100a test at a first time constant; S2, based on the test data, establishing a black box arc model, and through a numerical solution and a parameter optimization algorithm, fitting to obtain arc dissipation power and arc time constant corresponding to each set of test data, and then obtaining an opening critical value; S3, obtaining the contact opening distance and the main chamber gas pressure in the arc chamber corresponding to each set of test data, and inputting the arc opening critical parameter fitting model for fitting to determine the values of the first parameter, the second parameter, the third parameter and the fourth parameter; S4, for a to-be-predicted working condition, obtaining a second time constant and an arc time, and the contact opening distance and the main chamber gas pressure in the arc chamber under the working condition; through the arc opening critical parameter fitting model, obtaining a predicted value of the opening value under the working condition, and if the predicted value is greater than the opening critical value, it is determined that the opening is successful, otherwise, it is determined that the opening fails.

2. The method according to claim 1, wherein the asymmetric short-circuit current breaking result of the high-voltage SF6 circuit breaker is predicted. The equation expression of the black box arc model in S2 is: Wherein, g is the total arc conductance, u is the calculated arc voltage, t is the time, T is the arc time constant, P is the arc dissipation power, i is the arc current, and the total arc conductance g and the calculated arc voltage u in the formula are unknown quantities to be solved.

3. The method for predicting the asymmetrical short-circuit current interruption result of a high-voltage SF6 circuit breaker according to claim 2, characterized in that, The black box arc model is solved by using the Runge-Kutta method.

4. The method for predicting the asymmetrical short-circuit current interruption result of a high-voltage SF6 circuit breaker according to claim 2, characterized in that, After obtaining the total arc conductance g and the calculated arc voltage u, the error between the arc voltage test data and the calculated arc voltage is calculated; the error is taken as the objective function, and the arc time constant and the arc dissipation power that minimize the error are obtained by using the particle swarm algorithm as the opening critical parameters.

5. The method for predicting the asymmetrical short-circuit current interruption result of a high-voltage SF6 circuit breaker according to claim 4, characterized in that, The opening critical value is obtained from the opening critical parameters, and the value is the product of the arc voltage change rate and the arc current change rate calculated from the opening critical parameters, and the expression is: where K is the open-circuit threshold, P ′ is the optimized arc dissipation power, T ′ is the optimized arc time constant.

6. The method of claim 1, wherein the method is characterized by: The arc opening critical parameter fitting model includes an arc column segment model between arc contacts, a gas arc cooling model and a comprehensive influence factor model; in the arc column segment model between arc contacts, the longer the contact opening distance, the longer the arc contact distance, the greater the chamber gas pressure, the better the arc cooling effect, the greater the arc resistance, and the higher the arc voltage extinction peak value, and the product of the arc voltage change rate and the arc current change rate is greater; in the gas arc cooling model, the elongation of the arc is caused by the gas arc cooling, and the gas flow is determined by the chamber gas pressure, that is, the influence of the chamber gas pressure on the product of the arc voltage change rate and the arc current change rate; the comprehensive influence factor model includes the influence of other comprehensive influence factors on the product of the arc voltage change rate and the arc current change rate in addition to the arc column segment and the gas arc cooling model.

7. The method of claim 1, wherein the method further comprises: determining a ratio of the maximum current to the minimum current; and determining the ratio of the maximum current to the minimum current is less than 1.

2. The expression of the arc opening critical parameter fitting model is: Wherein, P is the optimized arc dissipation power, T is the optimized arc time constant, k1, k2, k3 and β are the first parameter, the second parameter, the third parameter and the fourth parameter respectively, l is the contact opening distance corresponding to the opening critical parameter, and p is the main chamber gas pressure in the arc chamber corresponding to the opening critical parameter.

8. The method of claim 1, wherein the method is characterized by: The time constants of the test data in S1 are the same, but the arc times are different.

9. An electronic device comprising a memory and a processor, said memory having stored thereon a computer program, characterized in that, The program, when executed by the processor, implements the method of any one of claims 1-8.

10. A computer-readable storage medium having stored thereon a computer program, characterized in that, The program, when executed by the processor, implements the method of any one of claims 1-8.

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