Method and system for evaluating lightning stroke energy suppression of 10kV overhead transmission line

Abstract

The invention discloses a method and system for evaluating lightning stroke inhibition energy of a 10kV overhead transmission line, and relates to the technical field of lightning protection of overhead transmission lines, and the method comprises the steps: collecting the data of the overhead transmission line, and constructing a partial element equivalent circuit model of a short lead and a multi-conductor transmission line model of a long lead; the method comprises the following steps: for an overhead transmission line system with a long lead and a short lead simultaneously, carrying out hybrid modeling on the long lead and the short lead, and analyzing lightning surge of a distribution network overhead transmission line; and the optimal lightning arrester configuration scheme is determined by performing simulation evaluation on different configuration schemes. According to the hybrid modeling method, the multi-conductor transmission line equation of the long wire and the partial element equivalent circuit model of the short wire are combined, propagation of lightning stroke surge is accurately analyzed, the lightning protection performance of the system is improved, the overall cost is reduced, and efficient and economical lightning protection is achieved.

Description

Technical Field

[0001] The invention relates to the technical field of lightning protection for overhead power transmission lines, and in particular to a method and system for evaluating lightning energy suppression for a 10kV overhead power transmission line. Background Art

[0002] The complex line configuration of the actual distribution network makes its lightning protection work more and more difficult. The irregular environmental structure and uneven connection between the towers make each position on the line different. The risk of lightning strike also varies with the position of the line. In actual use, in order to reduce the damage caused by lightning strikes to the line, lightning arresters are usually installed on the overhead lines of the distribution network to achieve the function of line lightning protection. However, the inconvenience of installing lightning arresters on each pole will significantly increase the protection cost and maintenance difficulty of the lightning arrester. Therefore, how to economically and efficiently protect the distribution network from lightning under the condition of installing a limited number of lightning arresters has become the focus of the power industry. Issues of concern: In past studies, domestic and foreign scholars have explored the impact of the distance between poles and towers on the lightning protection performance of arresters, but have not considered the changes in lightning performance characteristics along the line. Therefore, the conclusions drawn may not be sufficient to obtain the optimal installation design of arresters for complex distribution lines. If quantitative indicators of the lightning performance of a single pole or line segment can be obtained, the pole positions of different arrester configurations can be determined more accurately, thereby achieving the purpose of optimizing the overall lightning protection design using arresters. Therefore, when considering differentiated flashover protection for overhead distribution lines, the main existing problem is the lack of an effective and reasonable numerical evaluation method to investigate the single-pole flashover number.

[0003] In subtropical regions, overhead transmission lines of medium-voltage distribution networks are prone to lightning strikes. As we all know, distribution transformers are the most vulnerable equipment on overhead transmission lines. In China, in order to protect these transformers, transformer-specific lightning arresters need to be installed on the primary side of the transformer. Such lightning arresters can effectively suppress lightning surges from the power grid system and ensure the safety and reliability of the low-voltage power supply network. However, during lightning strikes, transformer-specific lightning arresters may experience instantaneous, high-amplitude energy absorption, resulting in permanent damage or functional failure, which can easily cause the overall collapse of the distribution system. Therefore, in actual operation, how to control the lightning absorption energy of transformer-specific lightning arresters has become a key issue in distribution network lightning protection. Summary of the invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is: the existing lightning protection method for overhead transmission lines has unsatisfactory lightning protection effect, high cost, and complex maintenance, as well as the problem of how to effectively suppress lightning energy and protect the safety and reliability of transmission lines and their ancillary equipment.

[0006] To solve the above technical problems, the present invention provides the following technical solutions: a method for evaluating the lightning energy suppression of a 10kV overhead transmission line, comprising collecting overhead transmission line data, constructing a partial element equivalent circuit model of a short conductor and a multi-conductor transmission line model of a long conductor; for an overhead transmission line system with both long conductors and short conductors, performing mixed modeling of the long conductors and the short conductors, and analyzing the lightning surge of the distribution network overhead transmission line; and determining the optimal arrester configuration scheme by performing simulation evaluation on different configuration schemes.

[0007] As a preferred solution of the method for evaluating 10kV overhead transmission line lightning energy suppression described in the present invention, the overhead transmission line data includes line length, tower spacing, conductor parameters, shielding line position, height, distribution transformer position and related parameters.

[0008] As a preferred solution of the method for evaluating the lightning energy suppression of 10kV overhead transmission lines of the present invention, the partial element equivalent circuit model of the short conductor includes dividing the short conductor into segments, and using the association matrix A to represent the topological relationship between all the segments after segmentation. sw Indicates that a mutually coupled circuit network is established, based on the potential-based inductance matrix L sw And the coefficient matrix P sw Analyze mutual coupling, use low-frequency grounding model to model some element equivalent circuits, and eliminate L sw and P sw The relationship between the matrix and the frequency is divided into L by the time delay effect. o,sw , L d,sw and P d,sw , the subscript "o" indicates that the matrix retains entries without delay, and the subscript "d" indicates that the matrix retains entries with delay. Based on the voltage and current sources, the modified node network equation of the full-wave partial element equivalent circuit model is established, which is expressed as:

[0009]

[0010] Among them, R sw is the resistance matrix, which represents the resistance in the equivalent circuit model of the short wire part, V sw ,I sw are the node voltage and branch current respectively. The subscript “n” indicates that it is not affected by the delay, and the subscript “b” indicates that it is affected by the delay. n,sw (t) is the node voltage not affected by the delay, I b,sw (t) is the branch current affected by the time delay effect, represents the transpose of the incidence matrix, U s,sw (t) is the voltage source of the short wire, I s,,sw (t) is the current variable of the short wire, is the capacitance parameter matrix P of the short wire s,sw is the inverse matrix of , and τ is the inter-segment delay time.

[0011] As a preferred solution of the method for evaluating the 10kV overhead transmission line lightning energy suppression of the present invention, the multi-conductor transmission line model of the long conductor includes modeling the long parallel conductors with the multi-conductor transmission line equation, using the unit length inductance and capacitance, the subscript "lw" represents the parameters of the long conductor, the equation is discretized in space along the line, and the spatially discrete node voltage V is used. lw (t) and branch current I lw (t) description, by solving the lightning electromagnetic pulse of indirect lightning on the overhead transmission line, the time domain coupling equation of the Agrawal lossy model of the overhead transmission line is constructed, which is expressed as:

[0012]

[0013] Among them, i i (x,t) and is the lightning current vector and scattered voltage vector on the multi-conductor line, L ij is the inductance matrix per unit length, representing the inductive coupling between conductors in a multi-conductor line. is the horizontal electric field along the conductor induced by lightning at the conductor height h, ξ ij (x, t) is the approximate transient ground impedance matrix, ξ ij The (x, t) convolution represents the voltage drop along the line caused by the lossy grounding, C ij is the capacitance per unit length matrix, representing the capacitive coupling between conductors in a multi-conductor line.

[0014] As a preferred solution of the method for evaluating the 10kV overhead transmission line lightning energy suppression of the present invention, the hybrid modeling includes completing the mutual coupling in the system equation when there are long wires and short wires in the system, and constructing a hybrid network equation of unknown voltage and current on the long wire and the short wire, which is expressed as:

[0015]

[0016] Among them, A represents the coupling relationship between the long wire and the short wire, L lw Represents the inductance matrix per unit length of a long wire, L m,o The equivalent circuit parameter matrix of some elements representing long wires and short wires, The transpose of the equivalent circuit parameter matrix of the long and short wires, C lw is the capacitance matrix per unit length of the long wire, is the transpose of the capacitance parameter matrix of the short wire, The coefficient matrix P representing the short wire o,sw The inverse matrix, V lw (t) is the node voltage of the long wire, V sw (t) is the node voltage of the short wire, I lw (t) is the branch current of the long wire, I sw (t) is the branch current of the short conductor, U lw,s (t) is the voltage source of the long wire, ξ(t) is the time delay effect function, L m,d is the potential inductance matrix, describing the mutual coupling between long wires and short wires under the time delay effect, L sw,d is the inductance matrix of the short wire under the time delay effect, is the transpose of the potential matrix, P m is the capacitance parameter matrix of the short wire.

[0017] As a preferred solution of the method for evaluating the 10kV overhead transmission line for suppressing lightning energy described in the present invention, the lightning surge analysis of the distribution network overhead transmission line includes analyzing the composition and structure of the distribution network overhead transmission line, the overhead transmission line includes three-phase bare conductors and shielded wires, the overall length of the line is 1 km, the impedances at both ends are matched, the span between the towers is 60m, there are 17 in total, numbered P1 to P17, the distribution transformer is installed on the middle pole P9, it is a double-column structure, the main side of the transformer is protected by a transformer-specific lightning arrester T; the line configuration is analyzed, the phase line is supported by an insulator, the insulator is installed on a metal cross arm on a concrete pole, the bare conductor radius is 7mm, the shielded wire radius is 4mm, and the shielded wire is supported above the center phase line by 0. 5m, the phase line spacing s is fixed at 0.5m, the phase line height H is fixed at 10m, and the concrete column spacing on both sides of the distribution transformer area is 1.5m; the configuration of the lightning arrester and grounding system includes the distribution transformer and the transformer-specific lightning arrester are located at the height of 5m and 7m respectively, the cross arms of the phase line, distribution transformer line and transformer-specific lightning arrester line are connected to a common grounding lead, the grounding lead radius is 5mm, and the grounding electrode of each pole uses a vertical rod with a length of 2m and a radius of 0.02m. The soil conductivity of the wet ground is 0.01S / m; the flashover on the insulator is modeled as a controlled switch using a destructive effect model, and the lightning arrester is modeled using the IEEE circuit model. Based on the surge energy under medium voltage, the distribution transformer is represented by an equivalent capacitance of 0.5nF.

[0018] As a preferred scheme of the method for evaluating the 10kV overhead transmission line lightning energy suppression described in the present invention, wherein: the determination of the optimal lightning arrester configuration scheme includes using simulation software to simulate different configuration schemes, simulating the system response under different lightning strike scenarios, calculating the protection effect and cost of each configuration scheme, and selecting different lightning arrester configuration schemes based on lightning strike frequency, terrain, and environment, and conducting an evaluation of the lightning arrester lightning energy through simulation.

[0019] Another object of the present invention is to provide a system for evaluating the lightning energy suppression of 10kV overhead transmission lines, which can analyze the lightning surge of the distribution network overhead transmission lines by performing mixed modeling of long conductors and short conductors for the overhead transmission line system where long conductors and short conductors coexist, thereby solving the problem of low reliability of the current overhead transmission line lightning protection technology.

[0020] As a preferred solution for evaluating the 10kV overhead transmission line lightning energy suppression system described in the present invention, it includes: a data acquisition module, a hybrid modeling module, and a simulation evaluation module; the data acquisition module is used to collect overhead transmission line data, construct a partial element equivalent circuit model of short conductors and a multi-conductor transmission line model of long conductors; the hybrid modeling module is used to perform hybrid modeling of long conductors and short conductors for an overhead transmission line system with both long conductors and short conductors, and analyze the lightning surge of the distribution network overhead transmission line; the simulation evaluation module is used to determine the best arrester configuration scheme by performing simulation evaluation on different configuration schemes.

[0021] A computer device comprises a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps of a method for evaluating a 10 kV overhead transmission line for suppressing lightning energy.

[0022] A computer-readable storage medium stores a computer program, which, when executed by a processor, implements the steps of a method for evaluating a 10 kV overhead transmission line for suppressing lightning energy.

[0023] Beneficial effects of the present invention: The method for evaluating the suppression of lightning strike energy of 10kV overhead transmission lines provided by the present invention can describe the electromagnetic behavior in the system in detail by constructing a partial element equivalent circuit model of a short conductor and a multi-conductor transmission line model of a long conductor, ensure the accuracy and reliability of the model, and make subsequent simulation and analysis have higher precision, thereby improving the protection effect of the system. The hybrid modeling method combines the multi-conductor transmission line equation of the long conductor and the partial element equivalent circuit model of the short conductor to accurately analyze the propagation of the lightning surge. This modeling method can capture the behavioral characteristics of different types of conductors under lightning surges, help identify and analyze potential risk points, and better formulate protection strategies to ensure the stability and safety of transmission lines under lightning strikes. The system response under different lightning strike scenarios is simulated by simulation software, and the protection effect and cost-effectiveness of each configuration scheme are evaluated, which not only improves the lightning protection performance of the system, but also reduces the overall cost, and realizes efficient and economical lightning protection. The present invention achieves better results in terms of reliability, safety and cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0025] Figure 1 An overall flow chart of a method for evaluating lightning energy suppression for a 10kV overhead transmission line provided in the first embodiment of the present invention.

[0026] Figure 2 An overhead distribution line configuration diagram with a distribution transformer at a concrete pole P9 for evaluating a method for suppressing lightning strike energy of a 10kV overhead transmission line provided in a first embodiment of the present invention.

[0027] Figure 3 An equivalent circuit diagram of a lightning arrester for evaluating a method for suppressing lightning energy of a 10kV overhead transmission line provided in the first embodiment of the present invention.

[0028] Figure 4 A VI characteristic diagram of a nonlinear resistor for evaluating a method for suppressing lightning energy of a 10kV overhead transmission line provided in the first embodiment of the present invention.

[0029] Figure 5 An overall flow chart of a system for evaluating 10kV overhead transmission line lightning energy suppression provided in the third embodiment of the present invention. DETAILED DESCRIPTION

[0030] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the drawings of the specification. Obviously, the described embodiments are part of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in the art without creative work should fall within the scope of protection of the present invention.

[0031] Example 1, reference Figure 1-Figure 4 , which is an embodiment of the present invention, provides a method for evaluating the lightning energy suppression of a 10kV overhead transmission line, comprising:

[0032] S1: Collect overhead transmission line data and construct partial element equivalent circuit models for short conductors and multi-conductor transmission line models for long conductors.

[0033] Furthermore, the overhead transmission line data includes line length, tower spacing, conductor parameters, shield wire location, height, distribution transformer location and related parameters.

[0034] It should be noted that the partial element equivalent circuit model of the short wire includes dividing the short wire into segments and expressing the topological relationship between all the segments using the association matrix A sw Indicates that a mutually coupled circuit network is established, based on the potential-based inductance matrix L sw And the coefficient matrix P sw Analyze mutual coupling, use low-frequency grounding model to model some element equivalent circuits, and eliminate L sw and P sw The relationship between the matrix and the frequency is divided into L by the time delay effect. o,sw , L d,sw and P d,sw , the subscript "o" indicates that the matrix retains entries without delay, and the subscript "d" indicates that the matrix retains entries with delay. Based on the voltage and current sources, the modified node network equation of the full-wave partial element equivalent circuit model is established, which is expressed as:

[0035]

[0036] Among them, R sw is the resistance matrix, which represents the resistance in the equivalent circuit model of the short wire part, V sw ,I sw are the node voltage and branch current respectively. The subscript “n” indicates that it is not affected by the delay, and the subscript “b” indicates that it is affected by the delay. n,sw (t) is the node voltage not affected by the delay, I b,sw (t) is the branch current affected by the time delay effect, represents the transpose of the incidence matrix, Us,sw (t) is the voltage source of the short wire, I s,,sw (t) is the current variable of the short wire, is the capacitance parameter matrix P of the short wire s,sw is the inverse matrix of , and τ is the inter-segment delay time.

[0037] It should also be noted that the multi-conductor transmission line model for long conductors includes modeling long parallel conductors using the multi-conductor transmission line equations, using unit length inductance and capacitance, the subscript "lw" represents the parameters of the long conductor, the equations are discretized in space along the line, and the spatially discretized node voltages V lw (t) and branch current I lw (t) description, by solving the lightning electromagnetic pulse of indirect lightning on the overhead transmission line, the time domain coupling equation of the Agrawal lossy model of the overhead transmission line is constructed, which is expressed as:

[0038]

[0039] Among them, i i (x,t) and is the lightning current vector and scattered voltage vector on the multi-conductor line, L ij is the inductance matrix per unit length, representing the inductive coupling between conductors in a multi-conductor line. is the horizontal electric field along the conductor induced by lightning at the conductor height h, ξ ij (x, t) is the approximate transient ground impedance matrix, ξ ij The (x, t) convolution represents the voltage drop along the line caused by the lossy grounding, C ij is the capacitance per unit length matrix, representing the capacitive coupling between conductors in a multi-conductor line.

[0040] It should also be noted that the overhead transmission line system can be composed of two types of conductors, long conductors and short conductors. Overhead conductors are considered to be long conductors, such as phase lines and shielding lines, which are relatively long, parallel to each other and to the ground, and are described using multi-conductor transmission line equations. Short conductors include metal components of poles and cross arms, ground leads, grounding grids, and metal structures of nearby buildings of concern. These short conductors can only be modeled using the partial element equivalent circuit method and cannot be obtained using the multi-conductor transmission line equations.

[0041] S2: For overhead transmission line systems with both long and short conductors, hybrid modeling of long and short conductors is performed to analyze lightning surges on distribution network overhead transmission lines.

[0042] Furthermore, hybrid modeling includes completing the coupling between the long and short wires in the system equations when there are both long and short wires in the system, and constructing the hybrid network equations of the unknown voltage and current on the long and short wires, which can be expressed as:

[0043]

[0044] Among them, A represents the coupling relationship between the long wire and the short wire, L lw Represents the inductance matrix per unit length of a long wire, L m,o The equivalent circuit parameter matrix of some elements representing long wires and short wires, The transpose of the equivalent circuit parameter matrix of the long and short wires, C lw is the capacitance matrix per unit length of the long wire, is the transpose of the capacitance parameter matrix of the short wire, The coefficient matrix P representing the short wire o,sw The inverse matrix, V lw (t) is the node voltage of the long wire, V sw (t) is the node voltage of the short wire, I lw (t) is the branch current of the long wire, I sw (t) is the branch current of the short conductor, U lw,s (t) is the voltage source of the long wire, ξ(t) is the time delay effect function, L m,d is the potential inductance matrix, describing the mutual coupling between long wires and short wires under the time delay effect, L sw,d is the inductance matrix of the short wire under the time delay effect, is the transpose of the potential matrix, P m is the capacitance parameter matrix of the short wire.

[0045] It should be noted that the analysis of lightning surges on overhead transmission lines of distribution networks includes the analysis of the composition and structure of overhead transmission lines of distribution networks. Overhead transmission lines include three-phase bare conductors and shielded wires. The overall length of the line is 1 km. The impedances at both ends are matched. The span between towers is 60m. There are 17 poles in total, numbered P1 to P17. The distribution transformer is installed on the middle pole P9, which is a double-column structure. The main side of the transformer is protected by a special arrester T for the transformer. Figure 2The configuration of a section of line at P9 is shown; the line configuration is analyzed, the phase line is supported by an insulator, and the insulator is installed on a metal cross arm on a concrete pole. The radius of the bare conductor is 7mm, the radius of the shielded wire is 4mm, and the shielded wire is supported 0.5m above the central phase line. The phase line spacing s is fixed at 0.5m, the phase line height H is fixed at 10m, and the spacing between concrete columns on both sides of the distribution transformer area is 1.5m; the configuration of the lightning arrester and grounding system includes the distribution transformer and the transformer-specific lightning arrester at heights of 5m and 7m respectively, the cross arms of the phase line, distribution transformer line and transformer-specific lightning arrester line are connected to a common ground lead, the radius of the ground lead is 5mm, and the grounding electrode of each pole uses a vertical rod with a length of 2m and a radius of 0.02m. The soil conductivity of the wet ground is 0.01S / m; the flashover on the insulator is modeled as a controlled switch using a destructive effect model, and the lightning arrester is modeled using the IEEE circuit model. Based on the surge energy under medium voltage, the distribution transformer is represented by an equivalent capacitance of 0.5nF, Figure 3-Figure 4 The adopted circuit and its VI characteristics of nonlinear resistors are shown.

[0046] It should also be noted that at present, transient simulation modeling for distribution network systems is mostly done by simulation software such as LIOV, CiLIV, TIDA, and ERM, all of which are developed from multi-transmission line models. The computational efficiency of these tools is generally high, but the coupling effect between different types of units is not well considered. The modeling method of the present invention mainly adopts multi-conductor transmission line model and partial equivalent element circuit model for modeling. The former is mainly for modeling long conductors such as overhead transmission lines and shielding lines, and the latter is mainly for modeling short conductors such as towers and grounding grids. This can more comprehensively analyze the coupling effect between different types of units. In lightning fault analysis, the analysis method used is relatively complex and does not have the characteristics of rapid positioning. At the same time, if the lightning energy of the entire overhead transmission line is to be more comprehensively evaluated, the operating calculation cost is relatively high. The calculation and analysis method of the present invention can not only more comprehensively evaluate the overall lightning energy with the advantage of low cost, but also complete the overall analysis with faster efficiency and higher accuracy. Traditional methods often only model a single type of conductor and ignore the interaction between long conductors and short conductors. The present invention uses hybrid modeling to comprehensively consider the electromagnetic characteristics and mutual coupling of different types of conductors, thereby improving the accuracy and reliability of lightning surge analysis.

[0047] S3: Determine the best arrester configuration scheme by simulating and evaluating different configuration schemes.

[0048] Furthermore, determining the best lightning arrester configuration scheme includes using simulation software to simulate different configuration schemes, simulating the system response under different lightning strike scenarios, calculating the protection effect and cost of each configuration scheme, selecting different lightning arrester configuration schemes based on lightning strike frequency, terrain, and environment, and evaluating the lightning strike energy of the lightning arrester through simulation.

[0049] It should be noted that reasonable protection and prevention of 10kV overhead transmission lines to suppress lightning energy must not only meet protection expectations, but also follow the principle of cost optimization. The present invention can analyze the impact of different lightning protection configurations on an overhead transmission line, and the absorption of lightning energy by transformer-specific lightning arresters under different protection schemes, including the impact of shielding wires, additional lightning arresters and grounding impedance.

[0050] It should also be noted that there is currently no clear guidance on the protection measures and installation rules for lightning arresters. The method of the present invention can guide the reasonable allocation of the number and location of lightning arresters to maximize the economic benefits of protection. Traditional lightning arrester configuration schemes often lack scientific simulation evaluation, which makes it difficult to balance protection effects and costs. The present invention scientifically determines the optimal lightning arrester configuration scheme through detailed simulation evaluation, thereby optimizing protection effects and costs.

[0051] Example 2, reference Figure 2-Figure 5 , which is an embodiment of the present invention, provides a method for evaluating the lightning energy suppression of a 10kV overhead transmission line. In order to verify the beneficial effects of the present invention, scientific demonstration is carried out through economic benefit calculation and simulation experiments.

[0052] First, the data of overhead transmission lines are collected. The data collection includes the physical and electrical parameters of overhead transmission lines. The specific parameters include line length (1 km), tower spacing (60 meters), conductor parameters (bare conductor radius 7 mm, shielding wire radius 4 mm), shielding wire position (0.5 meters above the center phase line), distribution transformer location and related parameters (installed on P9 tower, double-column structure, the main side is protected by transformer-specific lightning arrester T), the short conductor is segmented, and the correlation matrix A is used. sw Represents the topological relationship between all small segments, based on the potential distribution matrix L sw And the coefficient matrix P sw Analyze mutual coupling, use low-frequency grounding model to model some element equivalent circuits, and eliminate L sw and P swThe relationship between voltage and frequency is analyzed. The multi-conductor transmission line equation is used to model the long conductor. The electrical characteristics of the long conductor are described by the inductance and capacitance per unit length. The time domain coupling equation of the Agrawal lossy model is constructed. For the overhead transmission line system with both long and short conductors, hybrid modeling is performed. The coupling between the long conductor and the short conductor is completed in the system equation. The hybrid network equation of the unknown voltage and current on the long conductor and the short conductor is constructed. The lightning surge of the distribution network overhead transmission line is analyzed in detail through this model, and the impact of the lightning surge on the system is evaluated. Different configuration schemes are simulated and evaluated using simulation software, and the system response under different lightning strike scenarios is simulated. The protection effect and cost of each configuration scheme are calculated, and its economy and effectiveness are evaluated. Based on the simulation results, the optimal lightning arrester configuration scheme is determined to ensure that the cost is optimized while meeting the protection requirements. Refer to Table 1 to record and analyze the data.

[0053] Table 1 Data record table

[0054]

[0055] By comparison, it can be seen that configuration scheme 4 has the best protection effect, but the cost is also the highest, and it is suitable for use in specific high-risk areas; while configuration schemes 2 and 5 have a good balance between protection effect and cost, and are suitable for use in general areas. Overall, configuration scheme 6 performs well in all indicators, has high practicality and economy, and is recommended as the best lightning arrester configuration scheme in most cases.

[0056] Example 3, reference Figure 5 , as an embodiment of the present invention, provides a system for evaluating 10kV overhead transmission line lightning energy suppression, including a data acquisition module, a hybrid modeling module, and a simulation evaluation module.

[0057] The data acquisition module is used to collect overhead transmission line data, construct a partial element equivalent circuit model of short conductors and a multi-conductor transmission line model of long conductors; the hybrid modeling module is used to perform hybrid modeling of long and short conductors for overhead transmission line systems with both long and short conductors, and analyze lightning surges on distribution network overhead transmission lines; the simulation evaluation module is used to determine the optimal arrester configuration scheme by performing simulation evaluation on different configuration schemes.

[0058] If the function is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or the part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0059] The logic and / or steps represented in the flowchart or otherwise described herein, for example, can be considered as an ordered list of executable instructions for implementing logical functions, and can be embodied in any computer-readable medium for use by an instruction execution system, device or apparatus (such as a computer-based system, a system including a processor, or other system that can fetch instructions from an instruction execution system, device or apparatus and execute instructions), or in conjunction with such instruction execution systems, devices or apparatuses. For the purposes of this specification, "computer-readable medium" can be any device that can contain, store, communicate, propagate or transmit a program for use by an instruction execution system, device or apparatus, or in conjunction with such instruction execution systems, devices or apparatuses.

[0060] More specific examples of computer-readable media (a non-exhaustive list) include the following: an electrical connection with one or more wires (electronic device), a portable computer disk case (magnetic device), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disk read-only memory (CDROM). In addition, the computer-readable medium may even be a paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, followed by editing, deciphering, or processing in another suitable manner as necessary, and then stored in a computer memory.

[0061] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, multiple steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc. It should be noted that the above embodiments are only used to illustrate the technical solution of the present invention and are not limited. Although the present invention is described in detail with reference to the preferred embodiments, it should be understood by those skilled in the art that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

[0062] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A method for evaluating the lightning energy suppression of a 10kV overhead transmission line, characterized in that: include: Collect overhead transmission line data and construct partial element equivalent circuit models for short conductors and multi-conductor transmission line models for long conductors; For overhead transmission line systems with both long and short conductors, hybrid modeling of long and short conductors is performed to analyze lightning surges on distribution network overhead transmission lines. The best arrester configuration scheme is determined by simulating and evaluating different configuration schemes.

2. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 1, characterized in that: The overhead transmission line data includes line length, tower spacing, conductor parameters, shielding line position, height, distribution transformer position and related parameters.

3. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 2, characterized in that: The partial element equivalent circuit model of the short wire includes dividing the short wire into segments, and using the association matrix A to represent the topological relationship between all the segments after the segmentation. sw Indicates that a mutually coupled circuit network is established, based on the potential-based inductance matrix L sw And the coefficient matrix P sw Analyze mutual coupling, use low-frequency grounding model to model some element equivalent circuits, and eliminate L sw and P sw The relationship between the matrix and the frequency is divided into L by the time delay effect. o,sw , L d,sw and P d,sw , the subscript "o" indicates that the matrix retains entries without delay, and the subscript "d" indicates that the matrix retains entries with delay. Based on the voltage and current sources, the modified node network equation of the full-wave partial element equivalent circuit model is established, which is expressed as: Among them, R sw is the resistance matrix, which represents the resistance in the equivalent circuit model of the short wire part, V sw ,I sw are the node voltage and branch current respectively. The subscript "n" indicates that it is not affected by the delay, and the subscript "b" indicates that it is affected by the delay. n,sw (t) is the node voltage not affected by the delay, I b,sw (t) is the branch current affected by the time delay effect, represents the transpose of the incidence matrix, U s,sw (t) is the voltage source of the short wire, I s,sw (t) is the current variable of the short wire, is the capacitance parameter matrix P of the short wire s,sw is the inverse matrix of , and τ is the inter-segment delay time.

4. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 3, characterized in that: The multi-conductor transmission line model of the long conductor includes modeling the long parallel conductor with the multi-conductor transmission line equation, using the unit length inductance and capacitance, the subscript "lw" represents the parameters of the long conductor, the equation is discretized in space along the line, and the node voltage V is discretized in space. lw (t) and branch current I lw (t) description, by solving the lightning electromagnetic pulse of indirect lightning on the overhead transmission line, the time domain coupling equation of the Agrawal lossy model of the overhead transmission line is constructed, which is expressed as: Among them, i i (x,t) and is the lightning current vector and scattered voltage vector on the multi-conductor line, L ij is the inductance matrix per unit length, representing the inductive coupling between conductors in a multi-conductor line. is the horizontal electric field along the conductor induced by lightning at the conductor height h, ξ ij (x, t) is the approximate transient ground impedance matrix, ξ ij The (x, t) convolution represents the voltage drop along the line caused by the lossy grounding, C ij is the capacitance per unit length matrix, representing the capacitive coupling between conductors in a multi-conductor line.

5. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 4, characterized in that: The hybrid modeling includes completing the mutual coupling in the system equation when there are long wires and short wires in the system, and constructing the hybrid network equation of unknown voltage and current on the long wires and the short wires, which is expressed as: Among them, A represents the coupling relationship between the long wire and the short wire, L lw Represents the inductance matrix per unit length of a long wire, L m,o The equivalent circuit parameter matrix of some elements representing long wires and short wires, The transpose of the equivalent circuit parameter matrix of the long and short wires, C lw is the capacitance matrix per unit length of the long wire, is the transpose of the capacitance parameter matrix of the short wire, The coefficient matrix P representing the short wire o,sw The inverse matrix, V lw (t) is the node voltage of the long wire, V sw (t) is the node voltage of the short wire, I lw (t) is the branch current of the long wire, I sw (t) is the branch current of the short conductor, U lw,s (t) is the voltage source of the long wire, ξ(t) is the time delay effect function, L m,d is the potential inductance matrix, describing the mutual coupling between long wires and short wires under the time delay effect, L sw,d is the inductance matrix of the short wire under the time delay effect, is the transpose of the potential matrix, P m is the capacitance parameter matrix of the short wire.

6. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 5, characterized in that: The analysis of the lightning surge of the distribution network overhead transmission line includes analyzing the composition and structure of the distribution network overhead transmission line, the overhead transmission line includes a three-phase bare conductor and a shielded wire, the overall length of the line is 1 km, the impedances at both ends are matched, the span between the pole towers is 60m, there are 17 poles in total, numbered P1 to P17, the distribution transformer is installed on the middle pole P9, it is a double-column structure, and the main side of the transformer is protected by a transformer-specific lightning arrester T; Analyze the line configuration. The phase line is supported by insulators. The insulators are installed on metal cross arms on concrete poles. The radius of the bare conductor is 7mm, and the radius of the shielded wire is 4mm. The shielded wire is supported 0.5m above the center phase line. The phase line spacing s is fixed at 0.5m, the phase line height H is fixed at 10m, and the distance between the concrete columns on both sides of the distribution transformer area is 1.5m. The configuration of the arrester and grounding system includes the distribution transformer and transformer-specific arrester located at a height of 5m and 7m respectively, the cross arms of the phase line, distribution transformer line and transformer-specific arrester line are connected to a common ground lead with a radius of 5mm, and the grounding electrode of each pole uses a vertical rod of 2m in length and 0.02m in radius, and the soil conductivity of the wet ground is 0.01S / m; The flashover on the insulator is modeled as a controlled switch using the destructive effect model, the lightning arrester is modeled using the IEEE circuit model, and the distribution transformer is represented by an equivalent capacitance of 0.5nF based on the surge energy at medium voltage.

7. The method for evaluating the lightning energy suppression of a 10 kV overhead transmission line according to claim 6, characterized in that: The method of determining the optimal lightning arrester configuration scheme includes using simulation software to simulate different configuration schemes, simulating system responses under different lightning strike scenarios, calculating the protection effect and cost of each configuration scheme, selecting different lightning arrester configuration schemes based on lightning strike frequency, terrain, and environment, and evaluating the lightning strike energy of the lightning arrester through simulation.

8. A system using the method for evaluating 10 kV overhead transmission line lightning energy suppression as claimed in any one of claims 1 to 7, characterized in that: Including data acquisition module, hybrid modeling module, simulation evaluation module; The data acquisition module is used to collect overhead transmission line data and construct a partial element equivalent circuit model of a short conductor and a multi-conductor transmission line model of a long conductor; The hybrid modeling module is used to perform hybrid modeling of long conductors and short conductors for an overhead power transmission line system with both long conductors and short conductors, and analyze lightning surges of distribution network overhead power transmission lines; The simulation evaluation module is used to determine the best arrester configuration scheme by performing simulation evaluation on different configuration schemes.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method for evaluating lightning energy suppression for a 10 kV overhead transmission line according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method for evaluating lightning energy suppression of a 10 kV overhead transmission line according to any one of claims 1 to 7 are implemented.

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