External multi-gap lightning arrester volt-second characteristic curve estimation method, device and medium

Abstract

The invention relates to an external multi-gap lightning arrester volt-second characteristic curve estimation method and device and a medium, and the method comprises the steps: selecting at least two different standard lightning pulses to carry out the lightning stroke test of an external multi-gap lightning arrester test system, and obtaining an initial initial voltage and a corresponding initial lightning stroke damage effect value; constructing each standard lightning pulse voltage-time curve, obtaining a damage effect integral function, and obtaining an initial external multi-gap lightning arrester voltage-time curve in combination with the initial initial voltage and the initial lightning damage effect value; based on the initial voltage-time curve of the external multi-gap lightning arrester, parameter optimization is carried out by utilizing a genetic algorithm, the voltage-time curve of the external multi-gap lightning arrester is obtained, and equipment and a medium are used for realizing the method. Compared with the prior art, the method has the advantages that the volt-second characteristic curve of the external multi-gap lightning arrester is directly estimated by using the genetic algorithm, and the characteristic curve capable of accurately reflecting the influence of the lightning stroke on the power distribution network is obtained through a simple estimation method.

Description

Technical Field

[0001] The invention relates to the field of lightning protection for distribution networks in high voltage and insulation technology, and in particular to a method, equipment and medium for estimating a volt-second characteristic curve of an external multi-gap lightning arrester. Background Art

[0002] Transmission and distribution systems deliver electricity from power plants to power demand centers, such as industries and cities, which are usually far away from centralized power generation. Power companies must guarantee the reliability of power supply, that is, they must maintain power supply regardless of any unforeseen events or disturbances inside or outside the grid. In this context, lightning strikes are one of the most difficult disturbances to deal with in distribution networks, which, especially transformers, are susceptible to direct and indirect lightning strikes. To address this problem, different protection schemes have been proposed, mainly including lightning protection devices (SPDs) or lightning arresters, grounding systems, and spatial shielding device schemes. Regardless of the protection measures adopted, the impact of lightning strikes must always be studied, and the effectiveness of the protection scheme must be evaluated through modeling and simulation to verify that the electrical stress imposed on the equipment during the lightning strike event remains within its support range. For these studies, all components need to be fully modeled. The accuracy of modeling directly affects the reliability of lightning research. Existing modeling objects for lightning research include line insulators, poles, grounding, transformers and protection devices. For example, China's invention patent application "CN105184070A" provides a piecewise fitting method for calculating the volt-second characteristic curve based on the voltage integration method. This method uses the voltage integration method as the insulator flashover criterion, and combines the numerical analysis method to piecewise calculate the volt-second characteristic curve of the insulator string under non-standard waveforms, and performs continuous piecewise fitting correction. Although the lightning resistance of the distribution network is studied through insulator flashover, in actual applications, insulator flashover usually occurs in areas with high electric field strength. Therefore, its volt-second characteristic curve reflects more the breakdown characteristics of the insulator under specific conditions, which makes it unable to accurately reflect the impact of lightning strikes on the distribution network. In addition, the method provided by the invention patent application "CN105184070A" is relatively cumbersome and requires multiple piecewise fitting corrections.

[0003] Therefore, it is a technical problem to be solved to provide a simple volt-second characteristic curve estimation method that can accurately reflect the impact of lightning strikes on distribution networks. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and to provide a method, device and medium for estimating the volt-second characteristic curve of an external multi-gap lightning arrester. By integrating the three-electrode external gap of a lightning-type pulse and adjusting the integral curve parameters using a genetic algorithm, a real and effective curve can be constructed, providing favorable support for high-precision lightning strike research.

[0005] The purpose of the present invention can be achieved by the following technical solutions: According to a first aspect of the present invention, a method for estimating a volt-second characteristic curve of an external multi-gap arrester is provided, the method comprising: Building an external multi-gap lightning arrester test system, selecting at least two different standard lightning pulses to perform a lightning strike test on the external multi-gap lightning arrester test system, and obtaining an initial starting voltage and a corresponding initial lightning strike damage effect value; Constructing each of the standard lightning pulse voltage-time curves, and obtaining a damage effect integral function, and obtaining an initial external multi-gap arrester voltage-time curve in combination with the initial starting voltage and the initial lightning damage effect value; Based on the initial external multi-gap arrester voltage-time curve, a genetic algorithm is used to perform parameter optimization to obtain the external multi-gap arrester voltage-time curve.

[0006] As a preferred technical solution, the expression of the standard lightning pulse voltage-time curve is: , in, represents the peak voltage generated by the standard lightning pulse; A and B are both constants to be solved.

[0007] As a preferred technical solution, the method for solving the unknown constants A and B is: The objective function is to minimize the derivative of the double exponential function with respect to time, and its expression is: , Based on the objective function, the constants A and B are solved by the simplex search method, and the double exponential wave function is substituted to obtain the standard lightning pulse voltage-time curve.

[0008] As a preferred technical solution, the damage effect integral function expression is: , in, express moment; Indicates the breakdown time; Indicates the applied voltage due to a standard lightning pulse; Starting voltage; , represents an undetermined parameter, and k represents a constant.

[0009] As a preferred technical solution, the method for obtaining the initial external multi-gap arrester voltage-time curve includes: Based on the standard lightning pulse voltage-time curve, all standard lightning pulse voltage-time curves are obtained and plotted in the same coordinate system; Obtain the abscissa value of the intersection point of each standard lightning pulse voltage-time curve and the initial starting voltage, which is the abscissa value in the damage effect integral function. The value is combined with the corresponding initial lightning damage effect value, and the breakdown time of each standard lightning pulse is obtained by using the damage effect integral function, that is, value; Substitute the breakdown time into the standard lightning pulse voltage-time curve to obtain the horizontal coordinate: The vertical coordinate value of the value is used to obtain the target coordinate point; Connect all target coordinate points to obtain the initial external multi-gap arrester voltage-time curve.

[0010] As a preferred technical solution, the method for obtaining the voltage-time curve of the external multi-gap arrester includes: The curve parameters to be optimized are used as genes to encode chromosomes, and multiple chromosomes are randomly generated and initialized within the constraints. When , the genetic algorithm chromosome gene has only one, which is the starting voltage; when When , the genetic algorithm chromosome gene is the starting voltage and the parameters to be determined, and the starting voltage is the first gene of the chromosome.

[0011] Select at least two data points in the initial external multi-gap arrester voltage-time curve located in a preset time interval, and use the difference between the damage effect values ​​of the two data points as the fitness function; Calculating the fitness value of each chromosome based on the fitness function and performing selection, crossover and mutation based on the fitness value to generate a new population; Determine whether the new population meets the iteration termination condition. If so, the current new population is the optimal parameter set of the starting voltage and the parameters to be determined; otherwise, continue to iterate and solve.

[0012] As a preferred technical solution, the restriction condition includes coefficient constraint, which is expressed as: , And the starting voltage constraint, its expression is: ,in, The destructive discharge voltage indicating a 50% breakdown probability is a known value; express The standard deviation of the normal distribution.

[0013] As a preferred technical solution, the preset time interval is 1.5µs to 8µs.

[0014] According to a second aspect of the present invention, there is provided an electronic device, comprising a memory and a processor, wherein a computer program is stored in the memory, and the method described above is implemented when the processor executes the program.

[0015] According to a third aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the program implements the method described above when executed by a processor.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1) The volt-second characteristic curve of the multi-gap arrester is estimated by combining the integral method and the genetic algorithm, and the starting voltage and the undetermined parameter α in the destructive effect integral function or only the starting voltage is iteratively optimized by the genetic algorithm to obtain the optimal solution of the curve parameters. Compared with the existing technology of combining the integral method with the piecewise curve fitting method to obtain the volt-second characteristic curve, it is simpler and can find the global optimal solution, thereby improving the reliability and accuracy of the volt-second characteristic curve.

[0017] 2) The present invention directly estimates the volt-second characteristic curve of the multi-gap arrester, which can intuitively reflect the impact of lightning impulse on the distribution network, and is of great significance for evaluating the protection performance of the arrester. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a flow chart of the method of the present invention; Figure 2 It is a standard lightning impulse voltage-time curve diagram of the present invention; Figure 3 A schematic diagram of a chromosome of the genetic algorithm of the present invention; Figure 4 A circuit diagram of a three-stage gap arrester system in an embodiment of the present invention; Figure 5 The figure is a curve diagram of the verification results of the method of the present invention. DETAILED DESCRIPTION

[0019] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present invention.

[0020] Unless otherwise defined, the technical terms or scientific terms involved in this application should be understood by people with ordinary skills in the technical field to which this application belongs. The words "one", "a", "a", "the" and the like involved in this application do not indicate a quantitative limitation, and may represent the singular or plural. The terms "include", "comprise", "have" and any of their variations involved in this application are intended to cover non-exclusive inclusions; for example, a process, method, system, product or device that includes a series of steps or modules (units) is not limited to the listed steps or units, but may also include steps or units that are not listed, or may also include other steps or units inherent to these processes, methods, products or devices. The words "connect", "connected", "coupled" and the like involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. The "multiple" involved in this application refers to two or more. "And / or" describes the association relationship of associated objects, indicating that there may be three relationships, for example, "A and / or B" can represent: A exists alone, A and B exist at the same time, and B exists alone. The character " / " generally indicates that the objects before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific ordering of the objects.

[0021] Example 1 In order to solve the problem of lack of intuitive and accurate methods in the prior art to realize lightning strike research, this embodiment provides a method for estimating the volt-second characteristic curve of an external multi-gap lightning arrester. The process of the method is as follows: Figure 1 As shown, specifically including: S1. Build an external multi-gap lightning arrester test system, select at least two different standard lightning pulses (two different standard lightning pulses are selected in this embodiment) to perform a lightning strike test on the external multi-gap lightning arrester test system, and obtain the initial starting voltage and the corresponding initial lightning strike damage effect value.

[0022] S2. Construct each standard lightning pulse voltage-time curve and obtain the destructive effect integral function, and obtain the initial external multi-gap arrester voltage-time curve by combining the initial starting voltage and the initial lightning damage effect value.

[0023] S21. Construct standard lightning pulse voltage-time curve: The interruption or arc between the terminals caused by the 1.2 / 50µs standard voltage pulse applied to the multi-gap is modeled using the double exponential wave formula. Specifically, the expression of the double exponential wave formula is: , in, represents the peak voltage generated by the standard lightning pulse; A and B are both constants to be solved, and the solution method is: S211. Taking the minimization of the derivative of the double exponential function with respect to time as the objective function, its expression is: , S212. Based on the objective function, the simplex search method is used to solve the constants A and B, and the double exponential wave function is substituted to obtain the standard lightning pulse voltage-time curve.

[0024] After solving the above steps, we can get Figure 2 The center line is a solid line + dotted line standard lightning impulse 1 and standard lightning impulse 2 curve.

[0025] S22. Obtain the damage effect integral function: The discharge process in gaseous, liquid, and solid insulation depends on the magnitude and duration of the impulse voltage. Electric utilities must establish acceptable methods to evaluate the effects of nonstandard waveform voltage impulses on the electrical insulation of equipment. Any method ultimately adopted should be verified by laboratory testing. The discharge process that will lead to insulation breakdown is called the destructive effect (DE) of the applied impulse. An integral method has been proposed for the evaluation of DE for nonstandard voltage waveforms in oil-insulated transformers. In the literature, the DE of an insulation system voltage impulse is defined as , where e(t) is the applied voltage pulse, expressed as a function of time; K1 and K2 are constants that depend on the transformer surge test results.

[0026] The above formula is based on the premise that the transformer insulation can withstand a given voltage level K1 for a long time without significantly affecting its service life. DE is a function of voltage amplitude and time, and these two factors should not be given the same weight, and the constant K2 is introduced to allow some changes in the relative weight of voltage amplitude or time. The constants K1 and K2 of the transformer insulation system can be estimated by standard lightning pulse tests. The definition of this constant makes the integration method highly flexible; that is, when the values ​​of K1 and K2 are appropriate, the voltage-time curve is very close to the measured value and consistent with the observed data. Under this assumption, the expression of the integral function of the destructive effect is: , in which DE is a constant that depends on the type of insulation system and the applied voltage; Indicates the applied voltage caused by the standard lightning pulse; U0 The starting voltage, which depends on the type of gap and the applied pulse voltage; express moment; represents the breakdown time; k represents a constant, and in this embodiment, it is assumed that k=1.

[0027] In addition to the above formula, this embodiment also provides another damage effect integral function, which is expressed as follows: , represents the undetermined coefficient.

[0028] In this embodiment, the above two damage effect integral function forms are uniformly set as: ,in, , Represents the unknown parameter, k represents a constant, and the formula is derived by the integration method to evaluate DE. Its working principle is related to the energy required for dielectric breakdown. Therefore, it can be applied to multi-gap modeling under non-standard pulses.

[0029] S23. Obtain the initial external multi-gap arrester voltage-time curve: S231. Obtain all standard lightning pulse voltage-time curves based on the standard lightning pulse voltage-time curve, and plot them in the same coordinate system. The effect is as follows: Figure 2 shown.

[0030] S232, obtain the abscissa value of the intersection point of each standard lightning pulse voltage-time curve and the straight line where the initial starting voltage (known) is located, and the abscissa value is the destructive effect integral function Value Figure 2 In and , combined with the corresponding initial lightning damage effect value (known), namely Figure 2 At this time, since the corresponding standard lightning impulse voltage-time curve is known, the damage effect integral function can be used to calculate the breakdown time of each standard lightning pulse, that is, Value correspondence Figure 2 In and .

[0031] S233, substitute the breakdown time into the standard lightning pulse voltage-time curve, and obtain the horizontal coordinate The vertical coordinate value of the value is used to obtain the target coordinate point.

[0032] S234, connect all the target coordinate points to obtain the initial external multi-gap arrester voltage-time curve, that is, Figure 2 The "Ut curve" in .

[0033] S3. Based on the initial external multi-gap arrester voltage-time curve, a genetic algorithm is used to perform parameter optimization to obtain the external multi-gap arrester voltage-time curve.

[0034] S31. The curve parameters to be optimized are used as genes to encode and generate chromosomes. 50 chromosomes are randomly generated and initialized within the constraints. Specifically, the encoding effect is as follows: Figure 3 As shown, when When , the genetic algorithm chromosome gene has only one, which is Figure 3 The starting voltage in When , the genetic algorithm chromosome gene is the starting voltage and the parameters to be determined, and the starting voltage is the first gene of the chromosome.

[0035] Specifically, the restrictions include: The coefficient constraint expression is: , and the starting voltage constraint is expressed as: ,in, The destructive discharge voltage indicating a 50% breakdown probability is a known value; express The standard deviation of the normal distribution.

[0036] Among them, the method for determining the starting voltage constraint is to fit the experimental measurement value and its corresponding normal distribution. The results shown in Table 1 are obtained by fitting the experimental results of the positive polarity pulse presented to the normal distribution and following the procedure established in Section 15 of the IEEE4-2013 standard. In this case, corresponds to the standard deviation, while the confidence interval for the 95th percentile is shown in square brackets, and the p-value from the Kolmogorov-Smirnov test is 0.12.

[0037] Table 1 Analysis of positive pulse test results

[0038] Combining Table 1, we can see that The search space is defined as .

[0039] S32, select at least two data points in the interval of 1.5µs to 8µs from the initial external multi-gap arrester voltage-time curve. In this embodiment, two data points (Upa, tba) and (Upb, tbb) are selected, and the difference between the damage effect values ​​of the two data points is used as the fitness function, that is, .

[0040] S33. Based on the fitness function, the fitness value of each chromosome is calculated and selection, crossover and mutation are performed based on the fitness value to generate a new population. The mutation rate and selection rate are 0.4 and 0.5 respectively; the parent generation is selected using the tournament method to perform crossover to generate new individuals of the next generation.

[0041] S34, judging whether the new population satisfies the iteration termination condition, if so, the current new population is the optimal parameter set of the starting voltage and the undetermined parameters; otherwise, continuing the iteration solution.

[0042] Example 2 In order to verify the feasibility of the method proposed in Example 1, this embodiment compares the simulation results with the experimental measurement results. An external multi-gap arrester test system is built, and the experimental results corresponding to the 0.1m spacing under the positive polarity standard lightning pulse are considered. In this embodiment, the U50 and standard deviation used are 94kV and 3.1kV, respectively. The verification experiment measurement is carried out using a 400kv, 10kj four-stage Marx pulse generator, and a digital peak voltmeter is used to measure the impulse voltage through a 400kV resistor divider. The response time is less than 60ns, and the measurement accuracy is within the range of + / -3%. The breakdown time is directly measured by an oscilloscope recorded by a Yokogawa DL1520 digital oscilloscope with a bandwidth of 150MHz and a sampling rate of 200MS / s. The breakdown frequency and standard deviation of the flashover voltage for each voltage level are determined by 10 to 20 applied pulses. The applied voltage difference of consecutive intervals does not exceed 3% of the expected 50% interference discharge voltage.

[0043] The data points selected in this embodiment are (117.4 kV, 1.5 µs) and (184.3 kV, 0.76 µs). Based on the above two data points, the volt-second characteristic curve is estimated using the estimation method provided in Example 1. Specifically, the estimation results are shown in Table 2.

[0044] Table 2 Parameter estimation results of volt-second curve

[0045] And construct as Figure 4 The circuit shown reproduces the volt-second characteristic curve obtained in Table 2. The inductance is the inductance of the source high voltage side connection circuit and its value is 10µH; the value of the breakdown gap channel inductance is 1µH / m. Figure 4 The control module in the circuit is a switch that allows control of the simulated dielectric breakdown, and the reproduction result is shown in Figure 5. It can be seen that the Ut curves reproduced by the two curves are very close to the characteristic curves measured experimentally, and the average difference between the experimental value and the calculated value of curve 1 is 0.051µs, and the average difference between curve 2 is 0.049µs, which are both smaller than the average difference in the prior art. Figure 5 It can be seen that between 130 kV and 165 kV, the model of curve 2 performs better than that of curve 1, while the opposite is true between 100 kV and 120 kV.

[0046] In summary, the method proposed in Example 1 is reliable and has a smaller error than the results obtained by the prior art methods.

[0047] Example 3 In order to verify the method provided in Example 1, this embodiment conducted a test experiment, and firstly modeled the positive polarity pulse (instead of the standard lightning impulse) used for the test experiment. For each polarity and voltage level, 15 tests were conducted, and it was found that the difference in the basic insulation level (BIL) of the three-electrode gap under the two polarities was less than 4%, as shown in Table 3.

[0048] Table 3 Summary of three-electrode gap measurement results under standard positive polarity pulse

[0049] It can be seen that the basic insulation level (BIL) of the device does not depend on the polarity of the applied pulse. Therefore, this study only considers positive polarity pulses. A standard positive polarity pulse voltage-time curve is constructed based on the data in Table 3, and two data points are selected. In this embodiment, the data points corresponding to Level 4 and Level 7 are selected because their relative frequencies allow the assumption that the random behavior of the dielectric breakdown process can be ignored, namely (56.3 kV, 4.236µs) and (61.2 kV, 2.630µs). The method provided in Example 1 is used for parameter estimation, and the data shown in Table 4 can be obtained.

[0050] Table 4. Results of volt-second curve estimation parameters

[0051] From Table 4, we can see that the starting voltage values ​​obtained by the two curves are detailed and differ by 4.311%. In addition, in both cases, the value of the objective function is less than , which proves that the volt-second characteristic curve estimated by the method provided in Example 1 can more accurately reproduce the actual situation.

[0052] Example 4 The electronic device of the present invention includes a central processing unit (CPU), which can perform various appropriate actions and processes according to computer program instructions stored in a read-only memory (ROM) or loaded from a storage unit into a random access memory (RAM). In the RAM, various programs and data required for device operation can also be stored. The CPU, ROM and RAM are connected to each other via a bus. An input / output (I / O) interface is also connected to the bus.

[0053] Multiple components in the device are connected to the I / O interface, including: input units, such as keyboards, mice, 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 cards, modems, wireless communication 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 telecommunication networks.

[0054] The processing unit performs the various methods and processes described above, such as methods S1 to S3. For example, in some embodiments, methods S1 to S3 may be implemented as a computer software program, which is 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 a ROM and / or a communication unit. When the computer program is loaded into the RAM and executed by the CPU, one or more steps of methods S1 to S3 described above may be performed. Alternatively, in other embodiments, the CPU may be configured to execute methods S1 to S3 in any other appropriate manner (e.g., by means of firmware).

[0055] The functions described above herein may be performed at least in part by one or more hardware logic components. For example, without limitation, exemplary types of hardware logic components that may be used include: field programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), application specific standard products (ASSPs), systems on chips (SOCs), complex programmable logic devices (CPLDs), and the like.

[0056] The program code for implementing the method of the present invention can be written in any combination of one or more programming languages. These program codes can be provided to a processor or controller of a general-purpose computer, a special-purpose computer or other programmable data processing device, so that the program code, when executed by the processor or controller, enables the functions / operations specified in the flow chart and / or block diagram to be implemented. The program code can be executed entirely on the machine, partially on the machine, partially on the machine as a stand-alone software package and partially on a remote machine, or entirely on a remote machine or server.

[0057] In the context of the present invention, a machine-readable medium may be a tangible medium that may contain or store a program for use by or in conjunction with an instruction execution system, device, or equipment. A machine-readable medium may be a machine-readable signal medium or a machine-readable storage medium. A machine-readable medium may include, but is not limited to, electronic, magnetic, optical, electromagnetic, infrared, or semiconductor systems, devices, or equipment, or any suitable combination of the foregoing. A more specific example of a machine-readable storage medium may include an electrical connection based on one or more lines, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disk read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

[0058] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can easily think of various equivalent modifications or replacements within the technical scope disclosed by the present invention, and these modifications or replacements should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be based on the protection scope of the claims.

Claims

1. A method for estimating the volt-second characteristic curve of an external multi-gap arrester, characterized in that: The method includes: Building an external multi-gap lightning arrester test system, selecting at least two different standard lightning pulses to perform a lightning strike test on the external multi-gap lightning arrester test system, and obtaining an initial starting voltage and a corresponding initial lightning strike damage effect value; Constructing each of the standard lightning pulse voltage-time curves, and obtaining a damage effect integral function, and combining the initial starting voltage and the initial lightning damage effect value to obtain an initial external multi-gap arrester voltage-time curve; Based on the initial external multi-gap arrester voltage-time curve, a genetic algorithm is used to perform parameter optimization to obtain the external multi-gap arrester voltage-time curve.

2. A method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 1, characterized in that: The expression of the standard lightning pulse voltage-time curve is: ， in, represents the peak voltage generated by the standard lightning pulse; A and B are both constants to be solved.

3. A method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 2, characterized in that: The method to solve the unknown constants A and B is: The objective function is to minimize the derivative of the double exponential function with respect to time, and its expression is: ， Based on the objective function, the constants A and B are solved by the simplex search method, and the double exponential wave function is substituted to obtain the standard lightning pulse voltage-time curve.

4. The method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 1, characterized in that: The damage effect integral function expression is: ， in, express moment; Indicates the breakdown time; Indicates the applied voltage due to a standard lightning pulse; Starting voltage; , represents an undetermined parameter, and k represents a constant.

5. A method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 4, characterized in that: The method for obtaining the initial external multi-gap arrester voltage-time curve comprises: Based on the standard lightning pulse voltage-time curve, all standard lightning pulse voltage-time curves are obtained and plotted in the same coordinate system; Obtain the abscissa value of the intersection point of each standard lightning pulse voltage-time curve and the initial starting voltage, which is the abscissa value in the damage effect integral function. The value is combined with the corresponding initial lightning damage effect value, and the breakdown time of each standard lightning pulse is obtained by using the damage effect integral function, that is, value; Substitute the breakdown time into the standard lightning pulse voltage-time curve to obtain the horizontal coordinate: The vertical coordinate value of the value is used to obtain the target coordinate point; Connect all target coordinate points to obtain the initial external multi-gap arrester voltage-time curve.

6. The method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 1, characterized in that: The method for obtaining the voltage-time curve of the external multi-gap arrester includes: The curve parameters to be optimized are used as genes to encode chromosomes, and multiple chromosomes are randomly generated and initialized within the constraints. When , the genetic algorithm chromosome gene has only one, which is the starting voltage; when When , the genetic algorithm chromosome gene is the starting voltage and the parameters to be determined, and the starting voltage is the first gene of the chromosome; Select at least two data points in the initial external multi-gap arrester voltage-time curve located in a preset time interval, and use the difference between the damage effect values ​​of the two data points as the fitness function; Calculating the fitness value of each chromosome based on the fitness function and performing selection, crossover and mutation based on the fitness value to generate a new population; Determine whether the new population meets the iteration termination condition. If so, the current new population is the optimal parameter set of the starting voltage and the parameters to be determined; otherwise, continue to iterate and solve.

7. A method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 6, characterized in that: The restriction conditions include coefficient constraints, which are expressed as follows: , And the starting voltage constraint, its expression is: ,in, The destructive discharge voltage indicating a 50% breakdown probability is a known value; express The standard deviation of the normal distribution.

8. A method for estimating the volt-second characteristic curve of an external multi-gap arrester according to claim 6, characterized in that: The preset time interval is 1.5µs to 8µs.

9. An electronic device for estimating the volt-second characteristic curve of an external multi-gap lightning arrester, comprising a memory and a processor, wherein a computer program is stored in the memory, characterized in that: When the processor executes the program, the method according to any one of claims 1 to 8 is implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method according to any one of claims 1 to 8 is implemented.

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