Accelerated assessment system and method for lightning strike risk of transmission lines and storage medium

Abstract

This invention discloses an accelerated assessment system, method, and storage medium for lightning strike risk of transmission lines. The system obtains the potential at each point in the spatial electric field of the area to be assessed using a parallel algorithm. It then simulates the lightning cloud and downlink leader models of the area to be assessed to obtain the ground lightning distribution. Based on the ground flash density and backflashover tripping rate sub-models, bypass tripping rate sub-models, and induced lightning tripping rate sub-models of the area to be assessed, the backflashover tripping rate, bypass tripping rate, and induced lightning tripping rate of the transmission lines in the area to be assessed are calculated respectively. These rates are then combined to obtain the average lightning strike tripping rate of each tower of the transmission lines in the area to be assessed. The average lightning strike tripping rate is used to assess the lightning strike risk of the area to be assessed. Using this method, lightning strike risk assessment results can be obtained in a shorter time, improving the lightning protection capability and operational safety of the power system.

Description

Technical Field

[0001] This invention relates to the field of lightning strike risk assessment technology for power transmission lines, specifically to an accelerated lightning strike risk assessment system and method for power transmission lines, and a storage medium. Background Technology

[0002] In power systems, lightning strikes are one of the important factors affecting the safe and stable operation of transmission lines. In order to prevent damage to transmission lines from lightning strikes, it is necessary to assess the lightning strike risk of transmission lines. However, the existing lightning strike risk assessment models are complex to calculate and require a lot of computing resources and time, which makes it difficult to conduct real-time risk assessment and implement lightning protection measures.

[0003] Existing technology discloses "a method and system for real-time risk assessment of lightning strikes on transmission lines". This method determines the lightning-affected width of the line corridor based on the entropy weight-TOPSIS analysis method, and collects data of nearby lightning strike points based on this. Then, it considers two types of flashover tripping of transmission lines under lightning strike conditions, calculates based on real-time lightning location data, and combines risk classification methods to realize real-time lightning strike risk assessment from towers to lines. Although this method can assess the real-time lightning strike risk from towers to lines, the calculation process is still relatively complex and time-consuming because it requires calculation based on real-time lightning location data. Summary of the Invention

[0004] The purpose of this invention is to address the time-consuming and labor-intensive nature of existing technologies in calculating lightning risk assessments for transmission lines. Therefore, a new accelerated calculation method is urgently needed to improve the computational efficiency of lightning risk assessment models. This invention proposes an accelerated lightning risk assessment system, method, and storage medium for transmission lines. The system first uses a multi-threaded acceleration method to perform parallel calculations of the spatial field potential in the downlink leader channel and determines the downlink development point based on its potential. Then, it calculates the ground flash density in the area to be assessed. Using the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model, it obtains the backflashover tripping rate model, the side-strike tripping rate model, and the induced lightning tripping rate model for the transmission line, respectively. Then, based on the obtained ground flash density in the area to be assessed, it calculates the actual values ​​of these three tripping rates. Finally, it obtains the average lightning tripping rate of each tower of the transmission line in the area to be assessed based on the sum of the three tripping rates. Finally, it uses the average lightning tripping rate to assess the lightning risk. This invention effectively combines multi-threaded acceleration methods and data grouping algorithms, improving data computation efficiency while ensuring data accuracy. As a result, lightning strike risk assessment results can be obtained in a shorter time, providing real-time data support for the implementation of lightning protection measures and improving the lightning protection capability and operational safety of the power system.

[0005] To achieve this objective, the first aspect of the present invention proposes an accelerated assessment system for lightning strike risk of transmission lines, comprising: a ground lightning strike distribution module for parallel calculation of the initial potential and the equivalent surface charge density at each point in the spatial electric field of the area to be assessed, to obtain the actual potential at each point in the spatial electric field of the area to be assessed; using the actual potential at each point in the spatial electric field, establishing a thundercloud and downlink leader model, an oncoming leader model, and a transmission line model of the area to be assessed; and obtaining the ground lightning strike distribution of the area to be assessed by simulating the thundercloud and downlink leader model of the area to be assessed.

[0006] The tripping rate grouping calculation module is used to obtain the backflash tripping rate sub-model, the bypass tripping rate sub-model, and the induced lightning tripping rate sub-model of the transmission line in the area to be evaluated based on the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model, respectively. The ground lightning distribution in the area to be evaluated is used as the ground flash density, and the backflash tripping rate, bypass tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated are calculated based on the ground flash density and the backflash tripping rate sub-model, bypass tripping rate sub-model, and induced lightning tripping rate sub-model of the area to be evaluated, respectively.

[0007] The lightning risk assessment module is used to combine and calculate the backflashover tripping rate, backflashover tripping rate, and induced lightning tripping rate of the transmission line in the area to be assessed, so as to obtain the average value of the lightning tripping rate of each tower of the transmission line in the area to be assessed, and to assess the lightning risk of the area to be assessed by the average value of the lightning tripping rate.

[0008] Furthermore, the specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the region to be evaluated is as follows: The spatial electric field of the region to be evaluated is divided into n media, and artificial boundaries with set initial potentials are formed around each media. The potential inside the artificial boundary is obtained by iterative calculation based on the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding media. The potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The actual surface equivalent charge density of the media is obtained by using the new potential of the artificial boundary and the potential inside the artificial boundary. The actual surface equivalent charge density of the media is integrated with all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the media to all artificial boundaries. The potential contribution of the media to all artificial boundaries is used as the actual potential of the corresponding point of the media in the spatial electric field of the region to be evaluated. The actual potential of each point in the spatial electric field of the region to be evaluated is obtained by parallel calculation.

[0009] Furthermore, the method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: The formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows:

[0010]

[0011] In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface;

[0012] The new artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows:

[0013]

[0014] In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor. P Let S' be the surface polarization charge density, S' be the conductor surface, S'' be the interface between the two dielectrics, and V' be the conductor volume.

[0015] Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until convergence is obtained to obtain the potential inside the artificial boundary.

[0016] Furthermore, the potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The formula is as follows:

[0017] U r1 =U 11 +U 21 +…+U n1 (3)

[0018] Where U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

[0019] Furthermore, the specific method for establishing the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model of the region to be evaluated using the actual potentials at each point in the aforementioned spatial electric field is as follows: The calculation formula for establishing the thundercloud and downlink leader model of the region to be evaluated using the actual potentials at each point in the aforementioned spatial electric field is as follows:

[0020]

[0021] G(z) = 1 - (z / H) c (5)

[0022] H(z)=0.3α+0.7β (6)

[0023] α=e -(z-10) / 75 (7)

[0024] β=G(z) (8)

[0025] In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. P For the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3 ;

[0026] The calculation formula for establishing the oncoming leader model of the region to be evaluated using the actual potential at each point in the aforementioned spatial electric field is as follows:

[0027]

[0028] E = (UE) z x) / (Dx) (11)

[0029] Where U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E is the electric field strength of the remaining gap.

[0030] The specific method for establishing a transmission line model using the actual potential of each point in the aforementioned spatial electric field is as follows: the lightning protection wire, conductor, and tower are divided into cylindrical conductor micro-elements. By controlling the boundary potential of the cylindrical conductor micro-elements and calculating the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downlink leader, the transmission line model is obtained.

[0031] Furthermore, the specific method for obtaining the ground lightning distribution in the area to be evaluated by simulating the thundercloud and downlink leader model of the area to be evaluated is as follows: using the thundercloud and downlink leader model of the area to be evaluated and the actual potential of each point in the spatial electric field of the area to be evaluated, the position and potential of the potential development point of the downlink leader are continuously calculated. When the potential development point of the downlink leader changes abruptly, the simulation of one lightning strike process is completed. The above process is repeated until the simulation of t lightning strike processes is completed, and the coordinates of all lightning strike points are recorded to obtain the mesoscopic terrain ground lightning distribution.

[0032] Furthermore, the calculation formula for the back-off trip rate sub-model is as follows:

[0033] P f =N×g×P I ×η (12)

[0034]

[0035] In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h.

[0036] The calculation formula for the bypass tripping rate sub-model is as follows:

[0037]

[0038] f(I)=I max (0.1r max ) 1.54 (15)

[0039] In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BDis the lightning exposure width, f(I) is the lightning current probability density function, and r max is the maximum shielding failure striking distance;

[0040] The calculation formula of the induced lightning trip rate sub-model is as follows:

[0041]

[0042] y max = 25H C I / U 50％ (18)

[0043]

[0044] In the formula, P g is the induced lightning trip rate, D k is the distance from the direct strike point to the line, r c is the conductor striking distance, r g is the ground striking distance, H C is the distance from the tower conductor suspension point to the ground, y max is the flashover range of induced lightning, I is the induced lightning current, U 50％ is the 50% impulse flashover voltage of the insulator string, N g is the ground flash density of each region of the terrain to be evaluated, η is the arc building rate, η = 0.4, I C is the lightning current amplitude, and P(I) is the probability function of the lightning current amplitude distribution.

[0045] Furthermore, the backflash trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated are combined and calculated, and the calculation formula for the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated is as follows:

[0046]

[0047] In the formula, S is the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated, T is the total number of towers of the entire transmission line, m is the theoretically calculated lightning trip rate of the tower, m is the sum of the backflash trip rate, shielding failure trip rate, and induced lightning trip rate, and n is the number of tower bases;

[0048] The specific method for evaluating the lightning risk of the area to be evaluated through the average value of the lightning trip rate is as follows:

[0049] When m < 0.5S, it is considered that the lightning risk level of the towers in each region of the terrain to be evaluated is level I;

[0050] When 0.5S < m < S, it is considered that the lightning risk level of the towers in each region of the terrain to be evaluated is level II;

[0051] When S < m < 1.5S, it is considered that the lightning strike risk level of the transmission towers in each area of the terrain to be evaluated is level III;

[0052] When m > 1.5S, it is considered that the lightning strike risk level of the transmission towers in each area of the terrain to be evaluated is level IV.

[0053] A second aspect of the present invention proposes a method for accelerating the assessment of lightning strike risk of transmission lines, including:

[0054] Performing parallel calculations based on the set initial potential and set surface equivalent charge density of each point in the space electric field of the area to be evaluated to obtain the actual potential of each point in the space electric field of the area to be evaluated, using the actual potential of each point in the space electric field to establish a thundercloud and downward leader model, an oncoming leader model, and a transmission line model for the area to be evaluated respectively, and obtaining the ground lightning strike distribution of the area to be evaluated by performing simulation calculations on the thundercloud and downward leader model of the area to be evaluated;

[0055] Respectively obtaining a backflashover tripping rate sub-model, a shielding failure tripping rate sub-model, and an induced lightning tripping rate sub-model for the transmission line in the area to be evaluated based on the thundercloud and downward leader model, the oncoming leader model, and the transmission line model, using the ground lightning strike distribution of the area to be evaluated as the ground flash density, and respectively calculating the backflashover tripping rate, the shielding failure tripping rate, and the induced lightning tripping rate of the transmission line in the area to be evaluated according to the ground flash density and the backflashover tripping rate sub-model, the shielding failure tripping rate sub-model, and the induced lightning tripping rate sub-model;

[0056] Combining and calculating the backflashover tripping rate, the shielding failure tripping rate, and the induced lightning tripping rate of the transmission line in the area to be evaluated to obtain the average value of the lightning strike tripping rate of each transmission tower in the area to be evaluated, and evaluating the lightning strike risk of the area to be evaluated through the average value of the lightning strike tripping rate.

[0057] Furthermore, the specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the region to be evaluated is as follows: The spatial electric field of the region to be evaluated is divided into n media, and artificial boundaries with set initial potentials are formed around each media. The potential inside the artificial boundary is obtained by iterative calculation based on the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding media. The potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The actual surface equivalent charge density of the media is obtained by using the new potential of the artificial boundary and the potential inside the artificial boundary. The actual surface equivalent charge density of the media is integrated with all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the media to all artificial boundaries. The potential contribution of the media to all artificial boundaries is used as the actual potential of the corresponding point of the media in the spatial electric field of the region to be evaluated. The actual potential of each point in the spatial electric field of the region to be evaluated is obtained by parallel calculation.

[0058] Furthermore, the method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: The formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows:

[0059]

[0060] In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface;

[0061] The new artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows:

[0062]

[0063] In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor. P Let S' be the surface polarization charge density, S' be the conductor surface, S'' be the interface between the two dielectrics, and V' be the conductor volume.

[0064] Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until convergence is obtained to obtain the potential inside the artificial boundary.

[0065] Furthermore, the potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The formula is as follows:

[0066] U r1 =U 11 +U 21 +…+U n1 (3)

[0067] In the formula, U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

[0068] Furthermore, the specific method for establishing the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model of the region to be evaluated using the actual potentials at each point in the aforementioned spatial electric field is as follows: The calculation formula for establishing the thundercloud and downlink leader model of the region to be evaluated using the actual potentials at each point in the aforementioned spatial electric field is as follows:

[0069]

[0070] G(z) = 1 - (z / H) c ) (5)

[0071] H(z)=0.3α+0.7β (6)

[0072] α=e -(z-10) / 75 (7)

[0073] β=G(z) (8)

[0074] In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. P For the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3 ;

[0075] The calculation formula for establishing the oncoming leader model of the region to be evaluated using the actual potential at each point in the aforementioned spatial electric field is as follows:

[0076]

[0077] E = (UE) z x) / (Dx) (11)

[0078] Where U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E is the electric field strength of the remaining gap.

[0079] The specific method for establishing a transmission line model using the actual potential of each point in the aforementioned spatial electric field is as follows: the lightning protection wire, conductor, and tower are divided into cylindrical conductor micro-elements. By controlling the boundary potential of the cylindrical conductor micro-elements and calculating the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downlink leader, the transmission line model is obtained.

[0080] Furthermore, the specific method for obtaining the ground lightning distribution in the area to be evaluated by simulating the thundercloud and downlink leader model of the area to be evaluated is as follows: using the thundercloud and downlink leader model of the area to be evaluated and the actual potential of each point in the spatial electric field of the area to be evaluated, the position and potential of the potential development point of the downlink leader are continuously calculated. When the potential development point of the downlink leader changes abruptly, the simulation of one lightning strike process is completed. The above process is repeated until the simulation of t lightning strike processes is completed, and the coordinates of all lightning strike points are recorded to obtain the mesoscopic terrain ground lightning distribution.

[0081] Furthermore, the calculation formula for the back-off trip rate sub-model is as follows:

[0082] P f =N×g×P I ×η (12)

[0083]

[0084] In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h.

[0085] The calculation formula for the bypass tripping rate sub-model is as follows:

[0086]

[0087] f(I)=I max( 0.1r max ) 1.54 (15)

[0088] In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BD Let f(I) be the lightning exposure width, f(I) be the lightning current probability density function, and r be the lightning current probability density function. max This is the maximum circumduction distance;

[0089] The calculation formula for the induced lightning tripping rate sub-model is as follows:

[0090]

[0091] y max =25H C I / U 50％ (18)

[0092]

[0093] In the formula, Pg 为 Induced lightning trip rate, D k r is the distance from the point of impact to the line. c r is the conductor striking distance. g H is the ground impact distance. C y is the distance from the suspension point of the conductor on the tower to the ground. max U represents the flashover range of induced lightning, I represents the induced lightning current, and U represents the flashover range of induced lightning. 50％ 50% impulse flashover voltage of insulator string, N g Let I be the ground flash density in each area of ​​the terrain to be evaluated, and η be the arc-building rate, η = 0.4. C Let I be the amplitude of the lightning current, and P(I) be the probability function of the lightning current amplitude distribution.

[0094] Furthermore, the backflashover tripping rate, side-strike tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated are combined and calculated to obtain the average lightning tripping rate of each tower of the transmission line in the area to be evaluated, as follows:

[0095]

[0096] Wherein, S is the average value of the lightning trip rates of each base tower of the transmission lines in the area to be evaluated, T is the total number of towers of the entire transmission line, m is the theoretically calculated lightning trip rate of the tower, m is the sum of the back-strike trip rate, the shielding failure trip rate and the induced lightning trip rate, and n is the number of tower bases;

[0097] The specific method for evaluating the lightning risk of the area to be evaluated through the average value of the lightning trip rate is as follows:

[0098] When m < 0.5S, it is considered that the lightning risk level of the towers in each area of the terrain to be evaluated is Class I;

[0099] When 0.5S < m < S, it is considered that the lightning risk level of the towers in each area of the terrain to be evaluated is Class II;

[0100] When S < m < 1.5S, it is considered that the lightning risk level of the towers in each area of the terrain to be evaluated is Class III;

[0101] When m > 1.5S, it is considered that the lightning risk level of the towers in each area of the terrain to be evaluated is Class IV.

[0102] The third aspect of the present invention proposes a computer-readable storage medium. The computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the steps of the above method are implemented.

[0103] Advantages of the present invention:

[0104] The present invention performs parallel calculations on the spatial field potential in the downward leader channel through a multi-thread acceleration method, determines the downward development point according to its potential, then calculates the ground flash density of the area to be evaluated, and uses the thundercloud and downward leader model, the upward leader model and the transmission line model to obtain the back-strike trip rate model, the shielding failure trip rate model and the induced lightning trip rate model of the transmission line respectively. Then, according to the obtained ground flash density of the area to be evaluated, the actual values of the back-strike trip rate, the shielding failure trip rate and the induced lightning trip rate are calculated respectively, and according to the sum of the three trip rates, the average value of the lightning trip rates of each base tower of the transmission line in the area to be evaluated is obtained. Then, the average value of the lightning trip rate is used to evaluate the lightning risk. The present invention effectively combines the multi-thread acceleration method and the data grouping algorithm, improves the calculation efficiency of the lightning risk assessment model while ensuring the accuracy of the data, can obtain the lightning risk assessment result in a shorter time, thereby providing real-time data support for the implementation of lightning protection measures, and improving the lightning protection ability and operation safety of the power system. BRIEF DESCRIPTION OF THE DRAWINGS

[0105] Figure 1 It is a structural block diagram of a transmission line lightning risk acceleration assessment system of the present invention;

[0106] Figure 2 This is a schematic diagram illustrating the parallel calculation of the potential at each point in the spatial electric field of the region to be evaluated based on the artificial boundary region decomposition method in this invention.

[0107] Figure 3 This is a schematic diagram of the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model in this invention;

[0108] Figure 4 This is a schematic diagram illustrating the multi-threaded acceleration principle in this invention. Detailed Implementation

[0109] The specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0110] Example 1

[0111] The first aspect of this invention proposes an accelerated assessment system for lightning strike risk of transmission lines, such as... Figure 1 As shown, it includes a ground lightning strike distribution module, a tripping rate grouping calculation module, and a lightning strike risk assessment module;

[0112] The ground lightning distribution module is used to perform parallel calculations based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the area to be evaluated, to obtain the actual potential of each point in the spatial electric field of the area to be evaluated. Using the actual potential of each point in the spatial electric field, the lightning cloud and downlink leader model, the oncoming leader model and the transmission line model of the area to be evaluated are established respectively. By simulating the lightning cloud and downlink leader model of the area to be evaluated, the ground lightning distribution of the area to be evaluated is obtained.

[0113] The tripping rate grouping calculation module is used to obtain the backflash tripping rate sub-model, the bypass tripping rate sub-model, and the induced lightning tripping rate sub-model of the transmission line in the area to be evaluated based on the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model, respectively. The ground lightning distribution in the area to be evaluated is used as the ground flash density, and the backflash tripping rate, bypass tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated are calculated based on the ground flash density and the backflash tripping rate sub-model, bypass tripping rate sub-model, and induced lightning tripping rate sub-model of the area to be evaluated, respectively.

[0114] The lightning risk assessment module is used to combine and calculate the backflashover tripping rate, backflashover tripping rate, and induced lightning tripping rate of the transmission line in the area to be assessed, so as to obtain the average value of the lightning tripping rate of each tower of the transmission line in the area to be assessed, and to assess the lightning risk of the area to be assessed by the average value of the lightning tripping rate.

[0115] In the above technical solution, the specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the initial potential and the equivalent surface charge density at each point in the spatial electric field of the region to be evaluated is as follows: Figure 2 As shown, the spatial electric field of the region to be evaluated is divided into n media, with the surface potential of medium 1 being U1, the surface potential of medium 2 being U2, and the surface potential of medium n being U... n The process involves calculating the electric field around each medium. An artificial boundary with a set initial potential surrounds each medium. This artificial boundary should be located in the air and completely enclose each medium, placing the coal within its own enclosed space. First, the initial potential of the artificial boundary is assumed to be 0V. The potential inside the artificial boundary is calculated iteratively based on the initial potential and the corresponding surface equivalent charge density of the medium. Then, the potential contributions of the n media in the spatial electric field of the region to be evaluated to this artificial boundary are superimposed to obtain a new potential for the artificial boundary. The actual surface equivalent charge density of the medium is then obtained using the new potential and the internal potential. This actual surface equivalent charge density is integrated across all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the medium to all artificial boundaries. This potential contribution is used as the actual potential of the corresponding point in the spatial electric field of the region to be evaluated. Finally, a parallel algorithm is used to obtain the actual potential of each point in the spatial electric field of the region to be evaluated.

[0116] In the above technical solution, the method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: First, the formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows:

[0117]

[0118] In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface;

[0119] Then, the artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows:

[0120]

[0121] In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor.P σ is the surface polarization charge density, S′ is the conductor surface, S″ is the interface between two dielectrics, and V′ is the conductor volume;

[0122] Substitute the new artificial boundary potential into the above two formulas for iteration until convergence to obtain the potential inside the artificial boundary.

[0123] In the actual operation process, use the multi-thread acceleration method to calculate the n media in the spatial electric field of the area to be evaluated. As Figure 4 shown, use m PC machines to participate in the calculation of these n media (m < n). First, PC machines 1 - m calculate media 1 - m in sequence. For each PC machine, the following steps are sequentially solved for the medium it needs to calculate. For example, PC machine 1 corresponds to calculating medium 1. Step 1: Superimpose the potential contributions of the media in each partition (in this article, it refers to the area to be evaluated) to the artificial boundary (i.e., the artificial boundary of medium 1) to obtain the new potential of the artificial boundary; Step 2: Then, calculate the (equivalent) surface charge density of the medium in the partition from the potential of the artificial boundary and the internal points; Step 3: Use the (equivalent) surface charge density of the medium surface in the partition to integrate all artificial boundaries of the partitions to obtain the potential contribution of the medium to all artificial boundaries, and send it to other PC machines;

[0124] Secondly, the PC machine that first completes the above three steps calculates the (m + 1)-th medium (similarly, the above three steps are solved for medium m + 1), and the second PC machine that completes the above three steps calculates the (m + 2)-th medium, and so on. Each time an idle computer will continue to calculate the next medium in sequence until a PC machine calculates the n-th medium, and then the next idle PC machine starts to calculate from medium 1. In this way, it loops until the converged media exit the calculation queue, only calculating the media that have not converged. Eventually, all media converge and the calculation ends.

[0125] In the present invention, the data grouping algorithm is used to calculate the back-striking tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated. Although the grouping algorithm can calculate all data groups with possible lightning data, improving the calculation accuracy, the grouping algorithm increases the system operation consumption, and the time-consuming of grouped calculation can be reduced by multi-thread acceleration. The grouped calculation can be specifically decomposed into two parts: grouping and calculation. The calculation will cause confusion in the results during the actual test. The problem is judged that when CUDA multi-threads are called, the context needs to be processed. Therefore, the current multi-thread acceleration is the acceleration of the grouping process. After dividing the tasks for the loaded original data, the processing of each task is independent of each other. Since then, multi-threads can start to process the tasks. To ensure that each thread exclusively occupies the calculation, a mutex lock needs to be used to control the access to the calculation near the calculation interface call.

[0126] In the above technical solution, the formula for calculating the new potential of the artificial boundary by superimposing the potential contributions of n media in the spatial electric field of the region to be evaluated to the artificial boundary is as follows:

[0127] U r1 =U 11 +U 21 +…+U n1

[0128] In the formula, U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

[0129] In this paper, the actual surface equivalent charge density of the medium is integrated over all artificial boundaries within the spatial electric field of the region to be evaluated to obtain the potential contribution of the medium to all artificial boundaries as U. 11 U 21 …U n1 .

[0130] The established three-dimensional simulation model of lightning shielding for overhead transmission lines includes: a thundercloud and downlink leader model, an oncoming leader model, and a transmission line model, such as... Figure 3 As shown, the thundercloud and downlink leader model includes a downlink leader channel, a downlink leader stream region, and a point to be developed; the oncoming leader model includes an oncoming leader stream region and an oncoming leader channel; and the transmission line model includes towers, lightning protection wires, and transmission lines.

[0131] In the above technical solution, the calculation formula for establishing the thundercloud and downlink leader model of the region to be evaluated using the actual potential of each point in the spatial electric field is as follows:

[0132]

[0133] G(z) = 1 - (z / H) c )

[0134] H(z) = 0.3α + 0.7β

[0135] α=e -(z-10) / 75

[0136] β=G(z)

[0137] In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. PFor the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3 In this paper, the charge of the downlink leader channel can be inverted using the return stroke current waveform. If the time when the downlink leader reaches the ground is T0, and the time when the first return stroke current wave reaches the bottom of the cloud is T1, then the total charge obtained by integrating the return stroke current over the time interval ΔT = T1 - T0 is the total charge of the downlink leader channel. The charge distribution of the downlink leader channel can be calculated according to the formula proposed by Cooray. In this paper, the average duration of the return stroke is taken as 100 μs.

[0138] Furthermore, the specific method for obtaining the ground lightning distribution in the area to be evaluated by simulating the thundercloud and downlink leader model is as follows: The development of the downlink leader subtype is simulated using COMSOL simulation software. The location and potential of the potential development point of the downlink leader are continuously calculated using the thundercloud and downlink leader model of the area to be evaluated and the potential of each point in the spatial electric field of the area to be evaluated. When the potential development point of the downlink leader changes abruptly, the simulation of one lightning strike process is completed. The above process is repeated until the simulation of t lightning strike processes is completed, and the coordinates of all lightning strike points are recorded to obtain the mesoscopic terrain ground lightning distribution. In this paper, the judgment of the potential development point jump of the lightning downlink leader is as follows: when the average field strength between the uplink and downlink leaders or between the downlink leader and a target object that has not generated an uplink leader (an uplink leader refers to a phenomenon caused by a strong electric field on a target object, and the criterion is used to determine whether the target object generates an uplink leader) exceeds the average critical field strength of 500 kV / m, or when the uplink and downlink leaders meet, the final jump of the lightning strike occurs; the thundercloud potential is set to -200 MV; and the development step size is set to 20 m.

[0139] In this paper, the initiation and development process of a lightning frontal leader includes four main stages: initial corona initiation, streamer development, streamer leader transformation, and continuous development of the frontal leader. First, the surface electric field of the lightning conductor and the conductor is calculated, and the Peek criterion is used to determine whether the initial corona has started. After the initial corona has started, the length of the frontal streamer and the magnitude of the injected current of the lightning conductor and the conductor are calculated. When the temperature Th at the root of the streamer is greater than 1500K, the frontal leader is initiated. The space charge increment generated by the streamer in front of the frontal leader is calculated based on the distortion of the potential distribution. Finally, the development rate of the frontal leader is calculated based on the current injected into the leader head.

[0140] The formula for determining whether an initial corona discharge has started using the Peek criterion is as follows:

[0141]

[0142] In the formula, E c The critical corona initiation field strength (MV / m) for the lightning protection wire and conductor is given, where m is the roughness coefficient (0.9), δ is the relative air density (1.0), and r... c The radius of the lightning protection wire and the sub-conductor. When the average electric field strength is greater than the critical electric field strength E. c At that time, the initial corona discharge is determined.

[0143] In the above technical solution, the calculation formula for establishing the oncoming leader model of the region to be evaluated using the actual potential at each point in the spatial electric field is as follows:

[0144]

[0145] E = (UE) z x) / (Dx)

[0146] In the formula, U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E represents the electric field strength of the remaining gap.

[0147] In the above technical solution, the specific method for establishing a transmission line model using the actual potential of each point in the spatial electric field is as follows: the lightning protection wire, conductor and tower are divided into cylindrical conductor micro elements, the boundary potential of the cylindrical conductor micro elements is controlled, and the open domain dynamic three-dimensional electric field of the transmission line during the development of the downlink leader is calculated to obtain the transmission line model.

[0148] To calculate the backflashover trip rate, it is first necessary to calculate the backflashover trip level of the transmission line, and the calculation formula is as follows:

[0149]

[0150] In the formula, I represents the lightning withstand level of the line tower, and U... 50％ The voltage is the 50% impulse flashover voltage of the insulator, k is the coupling coefficient considering the effect of impulse corona, and h is... t h is the average height of the conductor above the ground. g R is the average height of the lightning protection wire above the ground, β is the current diversion coefficient of the tower, and R i h is the impulse grounding resistance of the tower. a h is the height of the crossarm. c L is the height of the conductor above the ground. t Let be the total inductance of the tower, and k0 be the geometric coupling coefficient between the conductor and the ground wire.

[0151] In this paper, based on the lightning withstand level of the transmission tower, the probability P of a lightning current greater than I can be calculated. I .

[0152] In the above technical solution, the calculation formula for the back-off tripping rate sub-model is as follows:

[0153] P f =N×g×P I ×η

[0154]

[0155] In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h.

[0156] The maximum lightning strike current around the line is calculated using the electrical geometric model method, and then the lightning strike trip rate is calculated using the exposure distance method. A sub-model of the lightning strike trip rate is obtained by calculating the lightning strike trip rate of the transmission line. In the above technical solution, the calculation formula for the lightning strike trip rate sub-model is as follows:

[0157]

[0158] f(I)=I max (0.1r max ) 1.54

[0159] In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BD Let f(I) be the lightning exposure width, f(I) be the lightning current probability density function, and r be the lightning current probability density function. max This represents the maximum distance for a circumferential strike.

[0160] In the above technical solution, the calculation formula for the induced lightning tripping rate sub-model is as follows:

[0161]

[0162] y max =25HC I / U 50％

[0163]

[0164] Wherein, P g is the induced lightning trip rate, D k is the distance from the direct strike point to the line, r c is the striking distance of the conductor, r g is the striking distance of the ground, H C is the distance from the suspension point of the tower conductor to the ground, y max is the flashover range of induced lightning, I is the induced lightning current, U 50％ is the 50% impulse flashover voltage of the insulator string, N g is the ground flash density of each area of the terrain to be evaluated, η is the arc building rate, η = 0.4, I C is the amplitude of the lightning current, and P(I) is the probability function of the lightning current amplitude distribution.

[0165] In the above technical solution, the back-strike trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated are combined and calculated, and the calculation formula for the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated is as follows:

[0166]

[0167] Wherein, S is the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated, T is the total number of towers of the entire transmission line, m is the theoretically calculated lightning trip rate of the tower, m is the sum of the back-strike trip rate, shielding failure trip rate, and induced lightning trip rate, and n is the number of tower bases.

[0168] The back-strike trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated are calculated respectively by using the data grouping algorithm. Dividing into small groups can perform a full permutation of the real data, and finally the arranged data is sent to the calculation interface to obtain the calculation result. Dividing into large groups uses the form of iterative matching to perform triangular matching on the data under each station, and calculates all possible data groups of the lightning data.

[0169] In the above technical solution, the specific method for evaluating the lightning risk of the area to be evaluated through the average value of the lightning trip rate is as follows: when m < 0.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is level I, and level I is a low risk; when 0.5S < m < S, it is considered that the lightning risk level of the towers in each area of the complex terrain is level II, and level II is a medium risk; when S < m < 1.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is level III, and level III is a high risk; when m > 1.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is level IV, and level IV is an extremely high risk.

[0170] Example 2

[0171] A second aspect of this invention proposes a method for accelerating the assessment of lightning strike risk on transmission lines, comprising:

[0172] Parallel calculations are performed based on the initial potential and the equivalent surface charge density at each point in the spatial electric field of the region to be evaluated to obtain the actual potential at each point in the spatial electric field of the region to be evaluated. Using the actual potential at each point in the spatial electric field, models of thunderclouds and downlink leaders, frontal leaders, and transmission lines are established for the region to be evaluated. By simulating the thunderclouds and downlink leaders of the region to be evaluated, the distribution of ground lightning strikes in the region to be evaluated is obtained.

[0173] Based on the aforementioned thundercloud and downlink leader model, frontal leader model, and transmission line model, the backflash trip rate sub-model, bypass trip rate sub-model, and induced lightning trip rate sub-model for the transmission lines in the area to be evaluated are obtained respectively. The ground lightning distribution in the area to be evaluated is used as the ground flash density. Based on the ground flash density and the backflash trip rate sub-model, bypass trip rate sub-model, and induced lightning trip rate sub-model for the area to be evaluated, the backflash trip rate, bypass trip rate, and induced lightning trip rate of the transmission lines in the area to be evaluated are calculated respectively.

[0174] The backflashover tripping rate, backflashover tripping rate, and induced lightning tripping rate of the transmission lines in the area to be evaluated are combined and calculated to obtain the average lightning tripping rate of each tower of the transmission lines in the area to be evaluated. The lightning risk of the area to be evaluated is then assessed by using the average lightning tripping rate.

[0175] In the above technical solution, the specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the initial potential and the equivalent surface charge density at each point in the spatial electric field of the region to be evaluated is as follows: Figure 2 As shown, the spatial electric field of the region to be evaluated is divided into n media, with the surface potential of medium 1 being U1, the surface potential of medium 2 being U2, and the surface potential of medium n being U... nThe process involves calculating the electric field around each medium. An artificial boundary with a set initial potential surrounds each medium. This artificial boundary should be located in the air and completely enclose each medium, placing the coal within its own enclosed space. First, the initial potential of the artificial boundary is assumed to be 0V. The potential inside the artificial boundary is calculated iteratively based on the initial potential and the corresponding surface equivalent charge density of the medium. Then, the potential contributions of the n media in the spatial electric field of the region to be evaluated to this artificial boundary are superimposed to obtain a new potential for the artificial boundary. The actual surface equivalent charge density of the medium is then obtained using the new potential and the internal potential. This actual surface equivalent charge density is integrated across all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the medium to all artificial boundaries. This potential contribution is used as the actual potential of the corresponding point in the spatial electric field of the region to be evaluated. Finally, a parallel algorithm is used to obtain the actual potential of each point in the spatial electric field of the region to be evaluated.

[0176] In the above technical solution, the method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: First, the formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows:

[0177]

[0178] In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface;

[0179] Then, the artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows:

[0180]

[0181] In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor. P Let S' be the surface polarization charge density, S' be the conductor surface, S'' be the interface between the two dielectrics, and V' be the conductor volume.

[0182] Substitute the new artificial boundary potential into the above two formulas and iterate until convergence is obtained to obtain the potential inside the artificial boundary.

[0183] In practice, a multi-threaded acceleration method is used to calculate the electric field of n media in the region to be evaluated, such as... Figure 4 As shown, m PCs are used to calculate this n media (m < n). First, PCs 1-m calculate media 1-m sequentially. Each PC performs the following steps for the media it is calculating. For example, PC 1 calculates media 1: Step 1: Superimpose the potential contribution of the media in each partition (in this paper, the area to be evaluated) to the artificial boundary (i.e., the artificial boundary of media 1) to obtain the new potential of the artificial boundary; Step 2: Calculate the (equivalent) surface charge density of the media in the partition from the potential of the artificial boundary and the potential of each point inside; Step 3: Integrate the obtained (equivalent) surface charge density of the media in the partition with the artificial boundaries of all partitions to obtain the potential contribution of the media to all artificial boundaries, and send it to the other PCs.

[0184] Next, the PC that first completes the above 3 steps calculates the (m+1)th medium (the same 3 steps are performed on medium m+1). The second PC that completes the above 3 steps calculates the (m+2)th medium, and so on. Each time a PC becomes available, it continues to calculate the next medium in sequence until a PC calculates the nth medium. Then, the next available PC starts calculating from medium 1. This cycle continues until a converged medium is removed from the calculation. Only the mediums that have not yet converged are calculated. Finally, all media converge, and the calculation ends.

[0185] In this invention, a data grouping algorithm is used to calculate the backflashover tripping rate, bypass tripping rate, and induced lightning tripping rate of the transmission lines in the area to be evaluated. Although the grouping algorithm can calculate all data groups with the possibility of lightning, improving the accuracy of the calculation, it increases the computational cost of the system. The time consumption of grouping calculation can be reduced by accelerating it with multithreading. The grouping calculation can be specifically decomposed into two parts: grouping and calculation. In actual testing, the calculation can cause confusion in the results. The problem is identified as the need to process the context when calling CUDA multithreads. Therefore, the current multithreading acceleration is to accelerate the grouping process. After dividing the loaded raw data into tasks, the processing of each task is independent. From this point, multithreaded processing of tasks can begin. To ensure that each thread has exclusive access to the calculation, a mutex lock is needed to control the accessibility of the calculation near the calculation interface.

[0186] In the above technical solution, the formula for calculating the new potential of the artificial boundary by superimposing the potential contributions of n media in the spatial electric field of the region to be evaluated to the artificial boundary is as follows:

[0187] U r1 =U 11 +U 21+…+U n1

[0188] Where U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

[0189] In this paper, the actual surface equivalent charge density of the medium is integrated over all artificial boundaries within the spatial electric field of the region to be evaluated to obtain the potential contribution of the medium to all artificial boundaries as U. 11 U 21 …U n1 .

[0190] The established three-dimensional simulation model of lightning shielding for overhead transmission lines includes: a thundercloud and downlink leader model, an oncoming leader model, and a transmission line model, such as... Figure 3 As shown, the thundercloud and downlink leader model includes a downlink leader channel, a downlink leader stream region, and a point to be developed; the oncoming leader model includes an oncoming leader stream region and an oncoming leader channel; and the transmission line model includes towers, lightning protection wires, and transmission lines.

[0191] In the above technical solution, the calculation formula for establishing the thundercloud and downlink leader model of the region to be evaluated using the actual potential of each point in the spatial electric field is as follows:

[0192]

[0193] G(z) = 1 - (z / H) c )

[0194] H(z) = 0.3a + 0.7β

[0195] α=e -(z-10) / 75

[0196] β=G(z)

[0197] In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. P For the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3In this paper, the charge of the downlink leader channel can be inverted using the return stroke current waveform. If the time when the downlink leader reaches the ground is T0, and the time when the first return stroke current wave reaches the bottom of the cloud is T1, then the total charge obtained by integrating the return stroke current over the time interval ΔT = T1 - T0 is the total charge of the downlink leader channel. The charge distribution of the downlink leader channel can be calculated according to the formula proposed by Cooray. In this paper, the average duration of the return stroke is taken as 100 μs.

[0198] Furthermore, the specific method for obtaining the ground lightning distribution in the area to be evaluated by simulating the thundercloud and downlink leader model is as follows: The development of the downlink leader subtype is simulated using COMSOL simulation software. The location and potential of the potential development point of the downlink leader are continuously calculated using the thundercloud and downlink leader model of the area to be evaluated and the potential of each point in the spatial electric field of the area to be evaluated. When the potential development point of the downlink leader changes abruptly, the simulation of one lightning strike process is completed. The above process is repeated until the simulation of t lightning strike processes is completed, and the coordinates of all lightning strike points are recorded to obtain the mesoscopic terrain ground lightning distribution. In this paper, the judgment of the potential development point jump of the lightning downlink leader is as follows: when the average field strength between the uplink and downlink leaders or between the downlink leader and a target object that has not generated an uplink leader (an uplink leader refers to a phenomenon caused by a strong electric field on a target object, and the criterion is used to determine whether the target object generates an uplink leader) exceeds the average critical field strength of 500 kV / m, or when the uplink and downlink leaders meet, the final jump of the lightning strike occurs; the thundercloud potential is set to -200 MV; and the development step size is set to 20 m.

[0199] In this paper, the initiation and development process of a lightning frontal leader includes four main stages: initial corona initiation, streamer development, streamer leader transformation, and continuous development of the frontal leader. First, the surface electric field of the lightning conductor and the conductor is calculated, and the Peek criterion is used to determine whether the initial corona has started. After the initial corona has started, the length of the frontal streamer and the magnitude of the injected current of the lightning conductor and the conductor are calculated. When the temperature Th at the root of the streamer is greater than 1500K, the frontal leader is initiated. The space charge increment generated by the streamer in front of the frontal leader is calculated based on the distortion of the potential distribution. Finally, the development rate of the frontal leader is calculated based on the current injected into the leader head.

[0200] The formula for determining whether an initial corona discharge has started using the Peek criterion is as follows:

[0201]

[0202] In the formula, E c The critical corona initiation field strength (MV / m) for the lightning protection wire and conductor is given, where m is the roughness coefficient (0.9), δ is the relative air density (1.0), and r is the coefficient of friction. cThe radius of the lightning protection wire and the sub-conductor. When the average electric field strength is greater than the critical electric field strength E... c At that time, the initial corona discharge is determined.

[0203] In the above technical solution, the calculation formula for establishing the oncoming leader model of the region to be evaluated using the actual potential at each point in the spatial electric field is as follows:

[0204]

[0205] E = (UE) z x) / (Dx)

[0206] Where U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E represents the electric field strength of the remaining gap.

[0207] In the above technical solution, the specific method for establishing a transmission line model using the actual potential of each point in the spatial electric field is as follows: the lightning protection wire, conductor and tower are divided into cylindrical conductor micro elements, the boundary potential of the cylindrical conductor micro elements is controlled, and the open domain dynamic three-dimensional electric field of the transmission line during the development of the downlink leader is calculated to obtain the transmission line model.

[0208] To calculate the backflashover trip rate, it is first necessary to calculate the backflashover trip level of the transmission line, and the calculation formula is as follows:

[0209]

[0210] In the formula, I represents the lightning withstand level of the line tower, and U... 50％ The voltage is the 50% impulse flashover voltage of the insulator, k is the coupling coefficient considering the effect of impulse corona, and h is... t h is the average height of the conductor above the ground. g R is the average height of the lightning protection wire above the ground, β is the current diversion coefficient of the tower, and R i h is the impulse grounding resistance of the tower. a h is the height of the crossarm. c L is the height of the conductor above the ground. t Let be the total inductance of the tower, and k0 be the geometric coupling coefficient between the conductor and the ground wire.

[0211] In this paper, the probability P of a lightning current greater than I can be calculated based on the lightning withstand level of the transmission tower. I P I The calculation formula is as follows:

[0212]

[0213] In the above technical solution, the calculation formula for the back-off tripping rate sub-model is as follows:

[0214] P f =N×g×P I ×η

[0215]

[0216] In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h.

[0217] The maximum lightning strike current around the line is calculated using the electrical geometric model method, and then the lightning strike trip rate is calculated using the exposure distance method. A sub-model of the lightning strike trip rate is obtained by calculating the lightning strike trip rate of the transmission line. In the above technical solution, the calculation formula for the lightning strike trip rate sub-model is as follows:

[0218]

[0219] f(I)=I max (0.1r max ) 1.54

[0220] In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BD Let f(I) be the lightning exposure width, f(I) be the lightning current probability density function, and r be the lightning current probability density function. max This represents the maximum distance for a circumferential strike.

[0221] In the above technical solution, the calculation formula for the induced lightning tripping rate sub-model is as follows:

[0222]

[0223]

[0224] y max =25H C I / U50％

[0225]

[0226] Where, P g is the induced lightning trip rate, D k is the distance from the direct strike point to the line, r c is the striking distance of the conductor, r g is the striking distance of the ground, H C is the distance from the suspension point of the tower conductor to the ground, y max is the flashover range of induced lightning, I is the induced lightning current, U 50％ is the 50% impulse flashover voltage of the insulator string, N g is the ground flash density of each area of the terrain to be evaluated, η is the arc building rate, η = 0.4, I C is the amplitude of the lightning current, P(I) is the probability distribution function of the lightning current amplitude.

[0227] In the above technical solution, the back-strike trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated are combined and calculated, and the calculation formula for the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated is as follows:

[0228]

[0229] Where, S is the average value of the lightning trip rate of each tower of the transmission line in the area to be evaluated, T is the total number of towers in the entire transmission line, m is the theoretically calculated lightning trip rate of the tower, m is the sum of the back-strike trip rate, shielding failure trip rate, and induced lightning trip rate, and n is the number of tower bases.

[0230] The back-strike trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated are calculated respectively by using the data grouping algorithm. Dividing into small groups can perform a full permutation of the real data, and finally the arranged data is sent to the calculation interface to obtain the calculation result. Dividing into large groups uses the form of iterative matching to perform triangular matching on the data under each station, and calculates all possible data groups of the lightning data.

[0231] In the above technical solution, the specific method for evaluating the lightning risk of the area to be evaluated through the average value of the lightning trip rate is as follows: When m < 0.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is Class I, and Class I is a low risk; when 0.5S < m < S, it is considered that the lightning risk level of the towers in each area of the complex terrain is Class II, and Class II is a medium risk; when S < m < 1.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is Class III, and Class III is a high risk; when m > 1.5S, it is considered that the lightning risk level of the towers in each area of the complex terrain is Class IV, and Class IV is an extremely high risk.

[0232] Example 3

[0233] A third aspect of the present invention provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the steps of the method described above.

[0234] Example 4

[0235] In a distributed network parallel programming environment based on MIP, a waveguide closed matrix region with PML as the cutoff boundary is used as a model in the electromagnetic field to solve its field strength distribution. A large-scale linear equation is obtained through the finite element method, and a parallel algorithm is used to solve it.

[0236] To compare whether the final solution vectors obtained by the serial and parallel algorithms are consistent, the same error tolerance is adopted. The serial and parallel algorithms are used to solve the problem respectively, and their iteration steps, running time, speedup ratio and parallel efficiency are tested and compared. The test results are shown in Table 1.

[0237] Table 1. Results of serial and parallel acceleration tests

[0238] Number of iterations Running time (s) acceleration ratio Parallel efficiency Serial 7824 1896 —— —— parallel 7819 1361 1.39 0.695

[0239] As can be seen from Table 1, there are some differences in the number of iteration steps. This is due to the influence of computational accuracy, which reduces the running time. Furthermore, the parallel implementation does not change the basic performance of the algorithm.

[0240] Then, with the same number of iterations, the execution time of the serial and parallel algorithms was tested, and the speedup and parallel efficiency, which reflect the parallel performance, were tested. The results are shown in Table 2.

[0241] Table 2. Test results of serial and parallel acceleration under the same number of iterations.

[0242]

[0243] As can be seen from Tables 1 and 2, parallel execution reduces runtime compared to serial execution. A serial program only starts one process, while a parallel program can start multiple processes. Windows is a multitasking operating system, meaning that the probability of using a parallel program is approximately n times that of a serial program, improving single-machine utilization and thus enhancing parallel performance.

[0244] This invention employs a multi-threaded acceleration method to perform parallel calculations of the spatial field potential in the downlink leader channel, determines the downlink development point based on its potential, and then calculates the ground flash density in the area to be evaluated. Using thundercloud and downlink leader models, oncoming leader models, and transmission line models, it obtains backflashover tripping rate models, bypass tripping rate models, and induced lightning tripping rate models for the transmission line, respectively. Then, based on the obtained ground flash density in the area to be evaluated, it calculates the actual values ​​of these three tripping rates. Finally, it obtains the average lightning tripping rate of each tower of the transmission line in the area to be evaluated based on the sum of the three tripping rates, and uses this average lightning tripping rate to assess lightning risk. This invention effectively combines a multi-threaded acceleration method and a data grouping algorithm, improving data calculation efficiency while ensuring data accuracy. Therefore, it can obtain lightning risk assessment results in a shorter time, providing real-time data support for the implementation of lightning protection measures and improving the lightning protection capability and operational safety of the power system.

[0245] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer storage media. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer storage medium implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0246] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer storage media according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A system that specifies functions in one or more boxes.

[0247] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including an instruction set implemented in a process. Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0248] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 A step that specifies a function in one or more boxes.

[0249] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

[0250] The contents not described in detail in this specification are existing technologies known to those skilled in the art.

Claims

1. A system for accelerating the assessment of lightning strike risk on power transmission lines, characterized in that, include: The ground lightning strike distribution module is used to perform parallel calculations based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the area to be evaluated, to obtain the actual potential of each point in the spatial electric field of the area to be evaluated. Using the actual potential of each point in the spatial electric field, the module establishes a thundercloud and downlink leader model, an oncoming leader model, and a transmission line model of the area to be evaluated. By simulating the thundercloud and downlink leader model of the area to be evaluated, the ground lightning strike distribution of the area to be evaluated is obtained. The tripping rate grouping calculation module is used to obtain the backflash tripping rate sub-model, the bypass tripping rate sub-model, and the induced lightning tripping rate sub-model of the transmission line in the area to be evaluated based on the thundercloud and downlink leader model, the oncoming leader model, and the transmission line model, respectively. The ground lightning distribution in the area to be evaluated is used as the ground flash density, and the backflash tripping rate, bypass tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated are calculated based on the ground flash density and the backflash tripping rate sub-model, bypass tripping rate sub-model, and induced lightning tripping rate sub-model of the area to be evaluated, respectively. The lightning strike risk assessment module is used to combine and calculate the backflashover trip rate, backflashover trip rate, and induced lightning trip rate of the transmission lines in the area to be assessed, so as to obtain the average value of the lightning strike trip rate of each tower of the transmission lines in the area to be assessed, and to assess the lightning strike risk of the area to be assessed by the average value of the lightning strike trip rate.

2. The accelerated assessment system for lightning strike risk of transmission lines according to claim 1, characterized in that, The specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the region to be evaluated is as follows: The spatial electric field of the region to be evaluated is divided into n media, and artificial boundaries with set initial potentials are formed around each media. The potential inside the artificial boundary is obtained by iterative calculation based on the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding media. The potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The actual surface equivalent charge density of the media is obtained by using the new potential of the artificial boundary and the potential inside the artificial boundary. The actual surface equivalent charge density of the media is integrated with all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the media to all artificial boundaries. The potential contribution of the media to all artificial boundaries is taken as the actual potential of the corresponding point in the spatial electric field of the region to be evaluated. The actual potential of each point in the spatial electric field of the region to be evaluated is obtained by parallel calculation.

3. The accelerated assessment system for lightning strike risk of transmission lines according to claim 2, characterized in that, The method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: The formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows: In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface; The new artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows: In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor. P Let S' be the surface polarization charge density, S' be the conductor surface, S'' be the interface between the two dielectrics, and V' be the conductor volume. Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until convergence is obtained to obtain the potential inside the artificial boundary.

4. The accelerated assessment system for lightning strike risk of transmission lines according to claim 3, characterized in that, The formula for calculating the new potential of the artificial boundary by superimposing the potential contributions of n media in the spatial electric field of the area to be evaluated on this artificial boundary is as follows: IN r1 =U 11 +U 21 +…+U n1 (3) In the formula, U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

5. The accelerated assessment system for lightning strike risk of transmission lines according to claim 4, characterized in that, The specific method for respectively establishing the thundercloud and downward leader model, the oncoming leader model, and the transmission line model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is: The formula for establishing the thundercloud and downward leader model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is as follows: G(z)=1-(z / H c ) (5) H(z) = 0.3α + 0.7β (6) α＝e -(z-10) / 75 (7) β = G(z) (8) In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. P For the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3 ; The formula for establishing the oncoming leader model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is as follows: E=(U-E z x) / (D-x) (11) In the formula, U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E is the electric field strength of the remaining gap. The specific method for establishing the transmission line model by using the actual potentials of each point in the spatial electric field is: Divide the shield wire, conductor, and tower into cylindrical conductor micro-elements, control the boundary potential of the cylindrical conductor micro-elements, and calculate the open-domain dynamic three-dimensional electric field of the transmission line during the development process of the downward leader to obtain the transmission line model.

6. The accelerated assessment system for lightning strike risk of transmission lines according to claim 5, characterized in that, The specific method for obtaining the ground lightning strike distribution of the area to be evaluated by simulating and calculating the thundercloud and downward leader model of the area to be evaluated is: Continuously calculate the position and potential of the potential development points of the lightning downward leader by using the thundercloud and downward leader model of the area to be evaluated and the actual potentials of each point in the spatial electric field of the area to be evaluated. When the potential development points of the lightning downward leader undergo a jump, a lightning strike process simulation is completed. Repeat the above process until the simulation of t lightning strike processes is completed, and record the coordinates of all lightning strike points to obtain the mesoscopic terrain ground lightning strike distribution.

7. The accelerated assessment system for lightning strike risk of transmission lines according to claim 6, characterized in that, The formula for the counterattack tripping rate sub-model is as follows: P f =N×g×P I × η (12) In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h. The formula for the shielding failure tripping rate sub-model is as follows: f(I)=I max (0.1r max ) 1.54 (15) In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BD Let f(I) be the lightning exposure width, f(I) be the lightning current probability density function, and r be the lightning current probability density function. max This is the maximum circumduction distance; The formula for the induced lightning tripping rate sub-model is as follows: y max =25H C I / U 50％ (18) In the formula, P g D is the tripping rate due to induced lightning. k r is the distance from the point of impact to the line. c For conductor striking distance, r g H is the ground impact distance. C y is the distance from the suspension point of the conductor on the tower to the ground. max U represents the flashover range of induced lightning, I represents the induced lightning current, and U represents the flashover range of induced lightning. 50％ 50% impulse flashover voltage of insulator string, N g Let I be the ground flash density in each area of ​​the terrain to be evaluated, and η be the arc-building rate, η = 0.

4. C Let I be the amplitude of the lightning current, and P(I) be the probability function of the lightning current amplitude distribution.

8. The accelerated assessment system for lightning strike risk of transmission lines according to claim 7, characterized in that, The formula for calculating the average value of the lightning strike tripping rates of each base tower of the transmission line in the area to be evaluated by combining and calculating the counterattack tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated is as follows: In the formula, S is the average value of the lightning strike tripping rates of each base tower of the transmission line in the area to be evaluated, T is the total number of towers of the entire transmission line, m is the theoretically calculated lightning strike tripping rate of the tower, m is the sum of the counterattack tripping rate, shielding failure tripping rate, and induced lightning tripping rate, and n is the number of tower bases; The specific method for evaluating the lightning strike risk of the area to be evaluated by the average value of the lightning strike tripping rate is: When m < 0.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class I; When 0.5S < m < S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class II; When S < m < 1.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class III; When m > 1.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class IV.

9. A method for accelerating the assessment of lightning strike risk on transmission lines, characterized in that, Including: Parallel calculations are performed based on the initial potential and the equivalent surface charge density at each point in the spatial electric field of the region to be evaluated to obtain the actual potential at each point in the spatial electric field of the region to be evaluated. Using the actual potential at each point in the spatial electric field, models of thunderclouds and downlink leaders, frontal leaders, and transmission lines are established for the region to be evaluated. By simulating the thunderclouds and downlink leaders of the region to be evaluated, the distribution of ground lightning strikes in the region to be evaluated is obtained. Based on the aforementioned thundercloud and downlink leader model, frontal leader model, and transmission line model, the backflash trip rate sub-model, bypass trip rate sub-model, and induced lightning trip rate sub-model for the transmission lines in the area to be evaluated are obtained respectively. The ground lightning distribution in the area to be evaluated is used as the ground flash density. Based on the ground flash density and the backflash trip rate sub-model, bypass trip rate sub-model, and induced lightning trip rate sub-model for the area to be evaluated, the backflash trip rate, bypass trip rate, and induced lightning trip rate of the transmission lines in the area to be evaluated are calculated respectively. The backflashover tripping rate, backflashover tripping rate, and induced lightning tripping rate of the transmission lines in the area to be evaluated are combined and calculated to obtain the average lightning tripping rate of each tower of the transmission lines in the area to be evaluated. The lightning risk of the area to be evaluated is then assessed by using the average lightning tripping rate.

10. The accelerated assessment method for lightning strike risk of transmission lines according to claim 9, characterized in that, The specific method for obtaining the actual potential of each point in the spatial electric field of the region to be evaluated by parallel calculation based on the set initial potential and set surface equivalent charge density of each point in the spatial electric field of the region to be evaluated is as follows: The spatial electric field of the region to be evaluated is divided into n media, and artificial boundaries with set initial potentials are formed around each media. The potential inside the artificial boundary is obtained by iterative calculation based on the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding media. The potential contributions of the n media in the spatial electric field of the region to be evaluated to the artificial boundary are superimposed to obtain the new potential of the artificial boundary. The actual surface equivalent charge density of the media is obtained by using the new potential of the artificial boundary and the potential inside the artificial boundary. The actual surface equivalent charge density of the media is integrated with all artificial boundaries in the spatial electric field of the region to be evaluated to obtain the potential contribution of the media to all artificial boundaries. The potential contribution of the media to all artificial boundaries is taken as the actual potential of the corresponding point in the spatial electric field of the region to be evaluated. The actual potential of each point in the spatial electric field of the region to be evaluated is obtained by parallel calculation.

11. The accelerated assessment method for lightning strike risk of transmission lines according to claim 10, characterized in that, The method for calculating the potential inside the artificial boundary by iterative calculation based on the initial potential of the artificial boundary and the equivalent surface charge density of the corresponding medium is as follows: The formula for calculating the equivalent surface charge density of the corresponding medium based on the initial potential of the artificial boundary is as follows: In the formula, σ is the equivalent surface charge density of the corresponding medium, and ε is the relative permittivity. To set the initial potential for the artificial boundary. e is a variable n The normal unit vector of the interface; The new artificial boundary potential is obtained by integrating the equivalent surface charge density of the corresponding medium. The calculation formula is as follows: In the formula, Let σ be the new artificial boundary potential, ρ be the surface charge density of the conductor, ρ be the known volume charge density, and R be the radius of the charged conductor. P Let S' be the surface polarization charge density, S' be the conductor surface, S'' be the interface between the two dielectrics, and V' be the conductor volume. Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until convergence is obtained to obtain the potential inside the artificial boundary.

12. The accelerated assessment method for lightning strike risk of transmission lines according to claim 11, characterized in that, The calculation formula for the new potential of the artificial boundary is obtained by superimposing the potential contributions of n media in the spatial electric field of the area to be evaluated on the artificial boundary as follows: IN r1 =U 11 +U 21 +…+U n1 (3) In the formula, U r1 For the new potential of this artificial boundary, U 11 U represents the potential contribution of medium 1 to the artificial boundary. 21 U represents the potential contribution of medium 2 to this artificial boundary. n1 Let n be the potential contribution of medium n to the artificial boundary.

13. The accelerated assessment method for lightning strike risk of transmission lines according to claim 12, characterized in that, The specific method for establishing the thundercloud and downward leader model, the oncoming leader model, and the transmission line model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is: The calculation formula for establishing the thundercloud and downward leader model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is as follows: G(z)=1-(z / H c ) (5) H(z) = 0.3α + 0.7β (6) α＝e -(z-10) / 75 (7) β = G(z) (8) In the formula, ρ s (ζ) represents the leader channel charge density C / m, and ζ represents the leader channel length, H. c Z represents the height of the thundercloud, z represents the height of the downlink leader head above the ground, and I represents the height of the downlink leader head above the ground. P For the return current amplitude in kA, the coefficient is taken as a0 = 1.476 × 10⁻⁶. -5 a = 4.857 × 10 -5 b = 3.9097 × 10 -6 c = 0.522, d = 3.73 × 10 -3 ; The calculation formula for establishing the oncoming leader model of the area to be evaluated by using the actual potentials of each point in the spatial electric field is as follows: E=(U-E z x) / (D-x) (11) In the formula, U lc The continuous leader initiation voltage is given by: h is the ground electrode height, d is the distance between the lower leader head and the target, v is the leader development velocity, k is the leader velocity development coefficient, U is the voltage across the gap, D is the gap length, x is the length of the leader that has already developed, and E is the leader velocity. Z E represents the electric field strength of the pilot channel. l0 E represents the minimum electric field strength required for the leader energy to continue to develop, and E is the electric field strength of the remaining gap. The specific method for establishing the transmission line model by using the actual potentials of each point in the spatial electric field is: The lightning protection wire, conductor, and tower are divided into cylindrical conductor micro-elements. By controlling the boundary potential of the cylindrical conductor micro-elements and calculating the open-domain dynamic three-dimensional electric field of the transmission line during the development process of the downward leader, the transmission line model is obtained.

14. The accelerated assessment method for lightning strike risk of transmission lines according to claim 13, characterized in that, The specific method for obtaining the ground lightning strike distribution of the area to be evaluated by simulating and calculating the thundercloud and downward leader model of the area to be evaluated is: By using the thundercloud and downward leader model of the area to be evaluated and the actual potentials of each point in the spatial electric field of the area to be evaluated, continuously calculate the position and potential of the potential development point of the lightning downward leader. When the potential development point of the lightning downward leader undergoes a jump, a lightning strike process simulation is completed. Repeat the above process until the simulation of t lightning strike processes is completed, and record the coordinates of all lightning strike points to obtain the mesoscopic terrain ground lightning strike distribution.

15. The accelerated assessment method for lightning strike risk of transmission lines according to claim 14, characterized in that, The calculation formula for the back flashover rate sub-model is as follows: P f =N×g×P I ×η (12) In the formula, P f To determine the tripping rate, N represents the total number of lightning strikes per year in the area to be evaluated, g represents the strike rate (1 / 6 for plains, 1 / 4 for mountains), and P... I Let I be the probability of a lightning current greater than I, and η be the arc-building rate, η = 0.4, N g The lightning density in each area of ​​the terrain to be evaluated is given by b, the distance between the two lightning rods is given by h, and the height of the lightning rod above the ground is given by h. The calculation formula for the shielding failure rate sub-model is as follows: f(I)=I max (0.1r max ) 1.54 (15) In the formula, P r Let N be the tripping rate due to the circuit breaker, η be the arc-building rate (η = 0.4), ΔL be the collector line segment of length ΔL, and N be the tripping rate due to the circuit breaker. g To assess the ground flash density in different terrain regions, I max I is the maximum current amplitude at which a flashover occurs. C For the amplitude of the lightning current, l BD Let f(I) be the lightning exposure width, f(I) be the lightning current probability density function, and r be the lightning current probability density function. max This is the maximum circumduction distance; The calculation formula for the induced lightning flashover rate sub-model is as follows: y max =25H C I / U 50％ (18) In the formula, P g D is the tripping rate due to induced lightning. k r is the distance from the point of impact to the line. c For conductor striking distance, r g H is the ground impact distance. C y is the distance from the suspension point of the conductor on the tower to the ground. max U represents the flashover range of induced lightning, I represents the induced lightning current, and U represents the flashover range of induced lightning. 50％ 50% impulse flashover voltage of insulator string, N g Let I be the ground flash density in each area of ​​the terrain to be evaluated, and η be the arc-building rate, η = 0.

4. C Let I be the amplitude of the lightning current, and P(I) be the probability function of the lightning current amplitude distribution.

16. The accelerated assessment method for lightning strike risk of transmission lines according to claim 15, characterized in that, The calculation formula for obtaining the average value of the lightning flashover rates of each base tower of the transmission line in the area to be evaluated by combining and calculating the back flashover rate, shielding failure rate, and induced lightning flashover rate of the transmission line in the area to be evaluated is as follows: In the formula, S is the average value of the lightning flashover rates of each base tower of the transmission line in the area to be evaluated, T is the total number of towers in the entire transmission line, m is the theoretical calculated lightning flashover rate of the tower, m is the sum of the back flashover rate, shielding failure rate, and induced lightning flashover rate, and n is the number of tower bases; The specific method for evaluating the lightning strike risk of the area to be evaluated by the average value of the lightning flashover rate is: When m < 0.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class I; When 0.5S < m < S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class II; When S < m < 1.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class III; When m > 1.5S, it is considered that the lightning strike risk level of the towers in each area of the terrain to be evaluated is Class IV.

17. A computer-readable storage medium storing a computer program, characterized in that: When the computer program is executed by the processor, it implements the steps of the method described in any one of claims 9 - 16.

Images