Power transmission line lightning stroke risk accelerated evaluation system and method and storage medium

Abstract

The invention discloses a power transmission line lightning stroke risk accelerated assessment system and method and a storage medium, and the method comprises the steps: obtaining the potential of each point in a space electric field of a to-be-assessed region according to a parallel algorithm, carrying out the simulation calculation of thundercloud and a downlink pilot model of the to-be-assessed region, and obtaining the ground thunderbolt distribution of the to-be-assessed region; according to the ground-to-ground lightning density of the to-be-evaluated region and the back-strike trip-out rate sub-model, the shielding failure trip-out rate sub-model and the inductive lightning trip-out rate sub-model, calculating the back-strike trip-out rate, the shielding failure trip-out rate and the inductive lightning trip-out rate of the power transmission line of the to-be-evaluated region respectively; and combining and calculating the back strike trip-out rate, the shielding failure trip-out rate and the inductive lightning trip-out rate of the power transmission line in the to-be-evaluated region to obtain an average value of the lightning trip-out rates of the base towers of the power transmission line in the to-be-evaluated region, and evaluating the lightning risk of the to-be-evaluated region through the average value of the lightning trip-out rates. By adopting the method, a lightning stroke risk assessment result can be obtained in a shorter time, and the lightning protection capability and the operation safety of the power system are improved.

Description

Technical Field

[0001] The present invention relates to the technical field of transmission line lightning strike risk assessment, and in particular to a transmission line lightning strike risk accelerated assessment system and method and a storage medium. Background Art

[0002] In the power system, lightning strike is one of the important factors affecting the safe and stable operation of transmission lines. In order to prevent damage to transmission lines caused by lightning strikes, it is necessary to assess the lightning strike risk of transmission lines. However, the calculation method of the existing lightning strike risk assessment model is complex and requires a lot of computing resources and time, which brings difficulties to real-time risk assessment and the implementation of lightning protection measures.

[0003] The prior art discloses "a real-time risk assessment method and system for 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 on nearby lightning strike points based on this. It then jointly considers two types of flashover tripping of transmission lines under lightning strike conditions, performs calculations based on real-time lightning location data, and combines risk grading methods to achieve real-time risk assessment of lightning strikes from poles to lines. Although this method can perform real-time risk assessment of lightning strikes from poles to lines, since this method needs to be calculated based on real-time lightning location data, its calculation process is still relatively complex and time-consuming. Summary of the invention

[0004] The purpose of the present invention is to solve the problem that the prior art is time-consuming and labor-intensive when calculating the lightning strike risk assessment of a transmission line. Therefore, a new accelerated calculation method is urgently needed to improve the calculation efficiency of the lightning strike risk assessment model, thereby proposing a transmission line lightning strike risk accelerated assessment system and method and storage medium. The system firstly calculates the spatial field potential in the downlink leader channel in parallel through a multi-threaded acceleration method, and judges the downlink development point according to its potential, and then calculates the ground lightning density in the area to be assessed, and uses the thundercloud and downlink leader model, the oncoming leader model and the transmission line model to respectively obtain the counter-attack tripping rate model, the shielding failure tripping rate model and the induced lightning tripping rate model of the transmission line, and then calculates the actual values ​​of the three tripping rates of the counter-attack tripping rate, the shielding failure tripping rate and the induced lightning tripping rate according to the obtained ground lightning density in the area to be assessed, and obtains the average value of the lightning tripping rate of each base tower of the transmission line in the area to be assessed according to the sum of the three tripping rates, and then uses the average value of the lightning tripping rate to assess the lightning risk. The present invention effectively combines the multi-threaded acceleration method and the data grouping algorithm, which improves the data calculation efficiency while ensuring the accuracy of the data. Therefore, the lightning strike risk assessment result can be obtained in a shorter time, thereby providing real-time data support for the implementation of lightning protection measures and improving the lightning protection capability and operation safety of the power system.

[0005] To achieve this purpose, the first aspect of the present invention proposes a transmission line lightning strike risk accelerated assessment system, comprising: a ground lightning distribution module for performing parallel calculations on the set initial potential and the set surface equivalent charge density of each point in the space electric field of the area to be assessed, obtaining the actual potential of each point in the space electric field of the area to be assessed, using the actual potential of each point in the space electric field to respectively establish a thundercloud and a downlink leader model, an oncoming leader model and a transmission line model of the area to be assessed, and simulating and calculating the thundercloud and the downlink leader model of the area to be assessed to obtain the ground lightning distribution in the area to be assessed;

[0006] The trip rate grouping calculation module is used to obtain the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model of the transmission line in the area to be evaluated according to the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, respectively, and take the ground lightning distribution in the area to be evaluated as the ground lightning density, and calculate the counter-attack trip rate, shielding failure trip rate and induced lightning trip rate of the transmission line in the area to be evaluated according to the ground lightning density and the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model;

[0007] The lightning strike risk assessment module is used to combine and calculate the counter-strike tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission lines in the area to be assessed, obtain the average value of the lightning strike tripping rate of each base tower of the transmission lines in the area to be assessed, and assess the lightning strike risk of the area to be assessed through the average value of the lightning strike tripping rate.

[0008] Furthermore, a specific method for performing parallel calculations based on the set initial potential and the 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 is as follows: the space electric field of the area to be evaluated is divided into n media, and the outer periphery of the medium has an artificial boundary with a set initial potential, and 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 medium, and the potential contribution of the n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed to obtain a new potential of the artificial boundary, and the actual surface equivalent charge density of the medium is obtained by using the new potential of the artificial boundary and the internal potential, and the actual surface equivalent charge density of the medium is integrated for all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and the potential contribution of the medium to all artificial boundaries is used as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and the actual potential of each point in the space electric field of the area to be evaluated is obtained by parallel calculation.

[0009] Furthermore, the potential inside the artificial boundary is calculated by iterative calculation according to the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium: the formula for calculating the set surface equivalent charge density of the corresponding medium according to the set initial potential of the artificial boundary is as follows:

[0010]

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

[0012] The artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows:

[0013]

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

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

[0016] Furthermore, the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed and the calculation formula for the new potential of the artificial boundary is obtained as follows:

[0017] U r1 =U 11 +U 21 +…+U n1 (3)

[0018] Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is the potential contribution of medium n to the artificial boundary.

[0019] Furthermore, the specific method of using the actual potential of each point in the space electric field to respectively establish the thundercloud and downlink leader model, the oncoming leader model and the transmission line model of the area to be evaluated is as follows: the calculation formula for establishing the thundercloud and downlink leader model of the area to be evaluated using the actual potential of each point in the space 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a 0 =1.476×10 -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 area to be evaluated using the actual potential of each point in the spatial electric field is as follows:

[0027]

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

[0029] Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the leader to continue to develop, and E is the residual gap electric field strength;

[0030] The specific method of establishing a transmission line model using the actual potential of each point in the spatial electric field is as follows: the lightning rod, the conductor and the tower are divided into cylindrical conductor elements, the boundary potential of the cylindrical conductor elements is controlled, and the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downward leader is calculated to obtain the transmission line model.

[0031] Furthermore, by simulating and calculating the thundercloud and downward leader model of the area to be evaluated, the specific method for obtaining the ground lightning distribution in the area to be evaluated is: using the thundercloud and downward 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 to 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 change, a simulation of the lightning strike process is completed, and 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 of the counter-tripping rate sub-model is as follows:

[0033] P f =N×g×P I ×η (12)

[0034]

[0035] Where P f is the strike-back tripping rate, N is the total number of lightning strikes in the area to be assessed, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between two lightning conductors, and h is the height of the lightning conductor above the ground;

[0036] The calculation formula of the shielding failure trip rate sub-model is as follows:

[0037]

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

[0039] Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, 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 conductor suspension point of the tower to the ground, y max is the flashover range of the 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 lightning current amplitude, and P(I) is the probability function of the lightning current amplitude distribution.

[0045] Furthermore, by combining and calculating the backflash trip rate, shielding failure trip rate, and induced lightning trip rate of the transmission line in the area to be evaluated, 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:

[0049] 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;

[0050] 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;

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

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

[0053] The 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 trip rate sub-model, a shielding failure trip rate sub-model, and an induced lightning trip rate sub-model for the transmission lines in the area to be evaluated according to 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 trip rate, the shielding failure trip rate, and the induced lightning trip rate of the transmission lines in the area to be evaluated according to the ground flash density and the backflashover trip rate sub-model, the shielding failure trip rate sub-model, and the induced lightning trip rate sub-model of the area to be evaluated;

[0056] Combining and calculating the backflashover trip rate, the shielding failure trip rate, and the induced lightning trip rate of the transmission lines in the area to be evaluated to obtain the average value of the lightning strike trip rates 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 trip rates.

[0057] Furthermore, a specific method for performing parallel calculations based on the set initial potential and the 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 is as follows: the space electric field of the area to be evaluated is divided into n media, and the outer periphery of the medium has an artificial boundary with a set initial potential, and 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 medium, and the potential contribution of the n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed to obtain a new potential of the artificial boundary, and the actual surface equivalent charge density of the medium is obtained by using the new potential of the artificial boundary and the internal potential, and the actual surface equivalent charge density of the medium is integrated for all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and the potential contribution of the medium to all artificial boundaries is used as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and the actual potential of each point in the space electric field of the area to be evaluated is obtained by parallel calculation.

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

[0059]

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

[0061] The artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows:

[0062]

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

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

[0065] Furthermore, the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed and the calculation formula for the new potential of the artificial boundary is obtained as follows:

[0066] U r1 =U 11 +U 21 +…+U n1 (3)

[0067] Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is the potential contribution of medium n to the artificial boundary.

[0068] Furthermore, the specific method of using the actual potential of each point in the space electric field to respectively establish the thundercloud and downlink leader model, the oncoming leader model and the transmission line model of the area to be evaluated is as follows: the calculation formula for establishing the thundercloud and downlink leader model of the area to be evaluated using the actual potential of each point in the space 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a 0 =1.476×10 -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 area to be evaluated using the actual potential of each point in the spatial electric field is as follows:

[0076]

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

[0078] Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the leader to continue to develop, and E is the residual gap electric field strength;

[0079] The specific method of establishing a transmission line model using the actual potential of each point in the spatial electric field is as follows: the lightning rod, the conductor and the tower are divided into cylindrical conductor elements, the boundary potential of the cylindrical conductor elements is controlled, and the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downward leader is calculated to obtain the transmission line model.

[0080] Furthermore, by simulating and calculating the thundercloud and downward leader model of the area to be evaluated, the specific method for obtaining the ground lightning distribution in the area to be evaluated is: using the thundercloud and downward 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 to 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 change, a simulation of the lightning strike process is completed, and 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 of the counter-tripping rate sub-model is as follows:

[0082] P f =N×g×P I ×η (12)

[0083]

[0084] Where P f is the strike-back tripping rate, N is the total number of lightning strikes in the area to be evaluated, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between the two lightning conductors, and h is the height of the lightning conductor above the ground;

[0085] The calculation formula of the shielding failure trip rate sub-model is as follows:

[0086]

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

[0088] Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, l BD is the lightning exposure width, f(I) is the lightning current probability density function, r max is the maximum impact distance;

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

[0090]

[0091] y max =25H C I / U 50％ (18)

[0092]

[0093] Where Pg 为 Induction lightning trip rate, D k is the distance from the direct hit point to the line, r c is the conductor striking distance, r g is the earth strike distance, H C y is the distance between the tower conductor suspension point and the ground, max is the flashover range of induced lightning, I is the induced lightning current, U 50％ Insulator string 50% impulse flashover voltage, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, η is the arcing rate, η=0.4, I C is the lightning current amplitude, and P(I) is the lightning current amplitude distribution probability function.

[0094] Furthermore, the strike-back tripping rate, shielding failure 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 value of the lightning tripping rate of each base tower of the transmission lines in the area to be evaluated. The calculation formula is as follows:

[0095]

[0096] Wherein, S is the average value of the lightning trip rates 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-stroke 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, which stores a computer program. 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-threaded 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-stroke 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-stroke trip rate, the shielding failure trip rate, and the induced lightning trip rate are calculated respectively, and the average value of the lightning trip rates of each tower of the transmission line in the area to be evaluated is obtained according to the sum of the three trip rates. Then, the average value of the lightning trip rate is used to evaluate the lightning risk. The present invention effectively combines the multi-threaded 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 It is a schematic diagram of the parallel calculation of the potential of each point in the spatial electric field of the area to be evaluated based on the artificial boundary region decomposition method in the present invention;

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

[0108] Figure 4 It is a schematic diagram of the multi-thread acceleration principle in the present invention. DETAILED DESCRIPTION

[0109] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention, and are not used to limit the present invention.

[0110] Example 1

[0111] The first aspect of the present invention provides a transmission line lightning risk accelerated assessment system, such as Figure 1 As shown, it includes a ground lightning distribution module, a trip rate grouping calculation module and a lightning risk assessment module;

[0112] The ground lightning distribution module is used to perform parallel calculations based on the set initial potential and the 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, and to establish the thundercloud and downlink leader model, the oncoming leader model and the transmission line model of the area to be evaluated respectively by using the actual potential of each point in the space electric field, and to obtain the ground lightning distribution in the area to be evaluated by simulating the thundercloud and downlink leader model of the area to be evaluated;

[0113] The trip rate grouping calculation module is used to obtain the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model of the transmission line in the area to be evaluated according to the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, respectively, and take the ground lightning distribution in the area to be evaluated as the ground lightning density, and calculate the counter-attack trip rate, shielding failure trip rate and induced lightning trip rate of the transmission line in the area to be evaluated according to the ground lightning density and the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model;

[0114] The lightning strike risk assessment module is used to combine and calculate the counter-strike tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission lines in the area to be assessed, obtain the average value of the lightning strike tripping rate of each base tower of the transmission lines in the area to be assessed, and assess the lightning strike risk of the area to be assessed through the average value of the lightning strike tripping rate.

[0115] In the above technical solution, the specific method of performing parallel calculation based on the set initial potential and the 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 is as follows: Figure 2 As shown, the spatial electric field of the area to be evaluated is divided into n media, and the surface potential of medium 1 is U 1 , the surface potential of medium 2 is U 2 , the surface potential of medium n is U n , it is necessary to calculate the electric field around each medium; the periphery of the medium has an artificial boundary with a set initial potential, the artificial boundary should be located in the air and the artificial boundary can completely surround each medium, so that the coal is in its own closed space. First, assume that the set initial potential of the artificial boundary is 0V, and iteratively calculate the potential inside the artificial boundary according to the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium, then superimpose the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary to obtain the new potential of the artificial boundary, and then use the new potential of the artificial boundary and the internal potential to obtain the actual surface equivalent charge density of the medium, integrate the actual surface equivalent charge density of the medium to all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and use the potential contribution of the medium to all artificial boundaries as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and use the parallel algorithm to obtain the actual potential of each point in the space electric field of the area to be evaluated.

[0116] In the above technical solution, the calculation method of the potential inside the artificial boundary is obtained by iteratively calculating the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium: first, the formula for calculating the set surface equivalent charge density of the corresponding medium according to the set initial potential of the artificial boundary is as follows:

[0117]

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

[0119] Then, the artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows:

[0120]

[0121] In the formula, is the new artificial boundary potential, σ is the conductor surface charge density, ρ is the known volume charge density, R is the radius of the charged conductor, σ P is the surface polarization charge density, S′ is the conductor surface, S″ is the interface of the 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 to calculate the medium it is responsible for, it performs the following steps in sequence. For example, PC machine 1 corresponds to calculating medium 1. Step 1: Superimpose the potential contributions of the media in each partition (referring to the area to be evaluated in this article) to this artificial boundary (i.e., the artificial boundary of medium 1) to obtain the new potential of the artificial boundary; Step 2: Then, find the (equivalent) surface charge density of the medium in the partition from the potential of the artificial boundary and the points inside; Step 3: Use the obtained (equivalent) surface charge density of the medium in this partition to integrate all artificial boundaries of the partitions to obtain the potential contribution of this 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 (also performs the above three steps of solution 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 a computer becomes idle, it 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, and so on in a loop. The media that reach convergence exit the calculation queue, and only the media that have not converged are calculated. Eventually, all media converge and the calculation ends.

[0125] In the present invention, a data grouping algorithm is used to respectively calculate the strike-back tripping rate, the shielding tripping rate, and the induced lightning tripping rate of the power transmission line in the area to be evaluated. Although the grouping algorithm can calculate all the data groups with the possibility of lightning data, and improve the accuracy of the calculation, the grouping algorithm increases the computing consumption of the system, and the time-consuming of the grouping calculation can be reduced by multi-threaded acceleration. The grouping calculation can be specifically decomposed into two parts: grouping and calculation. The calculation will cause confusion in the result during the actual test process. The problem is that the context needs to be processed when the CUDA multi-threaded call is judged, so the current multi-threaded acceleration is to accelerate the grouping process. After the loaded original data is divided into tasks, the processing of each task is independent of each other, and multi-threaded task processing can be started from then on. In order to ensure that each thread has exclusive calculation, it is necessary to use a mutex lock to control the accessibility of the calculation near the call calculation interface.

[0126] In the above technical solution, the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed and calculated to obtain the new potential of the artificial boundary. The calculation formula is as follows:

[0127] U r1 =U 11 +U 21 +…+U n1

[0128] Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is 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 in the space electric field of the area 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: thundercloud and downlink leader model, oncoming leader model and transmission line model, such as Figure 3 As shown, the thundercloud and downlink leader model include a downlink leader channel, a downlink leader flow area and a point to be developed, the oncoming leader model includes an oncoming leader flow area and an oncoming leader channel, and the transmission line model includes poles, lightning conductors and transmission lines.

[0131] In the above technical solution, the calculation formula for establishing the thundercloud and downlink leader model of the area 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a 0 =1.476×10 -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 downward leader channel can be inverted by the return current waveform. If the time when the downward leader reaches the ground is T 0 The time when the first return current wave reaches the bottom of the cloud is T 1 , then when ΔT=T 1 -T 0 The total charge obtained by integrating the return stroke current within the time interval is the total charge of the downward leader channel. The charge distribution of the downward leader channel can be calculated according to the formula proposed by Cooray. In this paper, the average return stroke duration is taken as 100μs.

[0138] Furthermore, by simulating and calculating the thundercloud and the downward leader model of the area to be evaluated, the specific method for obtaining the ground lightning distribution in the area to be evaluated is: using COMSOL simulation software to simulate the development of the lightning downward leader classification, and continuously calculating the position and potential of the potential development point of the lightning downward leader by using the thundercloud and the downward 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 lightning downward leader changes, the simulation of a lightning strike process is completed, and 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 article, the judgment of the transition of the potential development point of the downward leader of lightning is as follows: when the average field strength between the upward and downward leaders or between the downward leader and a target object that has not produced an upward leader (the upward leader refers to a phenomenon caused by a strong electric field on the target object, and the criterion is used to determine whether the target object has produced an upward leader) exceeds the average critical field strength of 500kV / m or the upward and downward leaders meet, the final transition of the lightning strike occurs; the thundercloud potential is set to -200MV; the development step is set to 20m.

[0139] In this paper, the initiation and development process of lightning oncoming leader includes four main stages: initial corona initiation, streamer development, streamer leader transformation and oncoming leader continuous development. Firstly, the surface electric field of lightning conductor and conductor is calculated, and the Peek criterion is used to determine whether the initial corona is initiated. After the initial corona is initiated, the oncoming streamer length and injection current of lightning conductor and conductor are calculated. When the temperature Th at the root of the streamer is greater than 1 500K, the oncoming leader is initiated. The space charge increment generated by the streamer in front of the oncoming leader is calculated according to the distortion of the potential distribution. Finally, the oncoming leader development speed is calculated according to the current injected into the leader head.

[0140] The calculation formula for determining whether the initial corona has started using the Peek criterion is:

[0141]

[0142] In the formula, E c is the corona initiation critical field strength of the lightning rod and conductor (MV / m), m is the roughness coefficient and is taken as 0.9, δ is the relative air density and is taken as 1.0, r c is the radius of the lightning conductor and the sub-conductor. When the average field strength is greater than the critical field strength E c When , it is determined that the initial corona starts.

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

[0144]

[0145] E=(UE zx) / (Dx)

[0146] Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the continuous development of the leader energy, and E is the residual gap electric field strength.

[0147] In the above technical scheme, the specific method of establishing a transmission line model using the actual potential of each point in the spatial electric field is: dividing the lightning rod, the conductor and the tower into cylindrical conductor elements, controlling the boundary potential of the cylindrical conductor elements, and calculating the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downstream leader, thereby obtaining a transmission line model.

[0148] To calculate the counter-tripping rate, we first need to calculate the counter-tripping level of the transmission line. The calculation formula is as follows:

[0149]

[0150] Where I is the lightning resistance level of the line tower, U 50％ is the 50% impulse flashover voltage of the insulator, k is the coupling coefficient considering the impact of the impulse corona, h t is the average height of the conductor above the ground, h g is the average height of the lightning conductor above the ground, β is the tower current shunt coefficient, R i is the tower impulse grounding resistance, h a is the cross arm height, h c is the height of the conductor to the ground, L t is the total inductance of the tower, k 0 is the geometric coupling coefficient between the conductor and the ground wire.

[0151] In this paper, according to the lightning resistance level of the line tower, the probability P of the lightning current greater than I can be obtained. I .

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

[0153] P f =N×g×P I ×η

[0154]

[0155] Where P fis the strike-back tripping rate, N is the total number of lightning strikes in the area to be evaluated, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between the two lightning conductors, and h is the height of the lightning conductor above the ground.

[0156] The maximum lightning strike current of the line is calculated according to the electrical geometry model method, and then the shielding trip rate of the line is calculated according to the exposure distance method. The shielding trip rate of the transmission line is calculated to obtain the shielding trip rate sub-model. In the above technical solution, the calculation formula of the shielding trip rate sub-model is as follows:

[0157]

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

[0159] Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, l BD is the lightning exposure width, f(I) is the lightning current probability density function, r max is the maximum impact distance.

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

[0161]

[0162] y max =25H C I / U 50％

[0163]

[0164] Where P g is the induced lightning trip rate, D k is the distance from the direct hit point to the line, r c is the conductor striking distance, r g is the earth strike distance, H C y is the distance between the tower conductor suspension point and the ground, max is the flashover range of induced lightning, I is the induced lightning current, U 50％ Insulator string 50% impulse flashover voltage, Ng Let \(N\) be the cloud-to-ground lightning density of each region of the terrain to be evaluated, \(\eta\) be the arc formation rate, \(\eta = 0.4\), \(I\) C is the lightning current amplitude, and \(P(I)\) is the probability distribution function of the lightning current amplitude.

[0165] In the above technical solution, the back flashover tripping rate, shielding failure tripping rate, and induced lightning tripping 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 tripping rate of each tower of the transmission line in the area to be evaluated is as follows:

[0166]

[0167] In the formula, \(S\) is the average value of the lightning tripping 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 tripping rate of the tower, \(m\) is the sum of the back flashover tripping rate, shielding failure tripping rate, and induced lightning tripping rate, and \(n\) is the number of tower bases.

[0168] The data grouping algorithm is used to calculate the back flashover tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated respectively. Dividing into small groups can perform a full permutation of the real data, and finally send the arranged data 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 strike risk of the area to be evaluated through the average value of the lightning tripping rate is as follows: when \(m \lt 0.5S\), it is considered that the lightning strike risk level of the towers in each region of the complex terrain is level I, and level I is a low risk; when \(0.5S \lt m \lt S\), it is considered that the lightning strike risk level of the towers in each region of the complex terrain is level II, and level II is a medium risk; when \(S \lt m \lt 1.5S\), it is considered that the lightning strike risk level of the towers in each region of the complex terrain is level III, and level III is a high risk; when \(m \gt 1.5S\), it is considered that the lightning strike risk level of the towers in each region of the complex terrain is level IV, and level IV is an extremely high risk.

[0170] Embodiment 2

[0171] The second aspect of the present invention proposes a method for accelerating the evaluation of the lightning strike risk of a transmission line, including:

[0172] 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 lightning cloud and downward leader model, an oncoming leader model, and a transmission line model of the area to be evaluated respectively, and obtaining the ground lightning strike distribution of the area to be evaluated through simulation calculations of the lightning cloud and downward leader model of the area to be evaluated;

[0173] According to the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, respectively obtain the counter-attack tripping rate sub-model, the shielding failure tripping rate sub-model and the induced lightning tripping rate sub-model of the transmission line in the area to be evaluated, take the ground lightning distribution in the area to be evaluated as the ground lightning density, and respectively calculate the counter-attack tripping rate, shielding failure tripping rate and induced lightning tripping rate of the transmission line in the area to be evaluated according to the ground lightning density and the counter-attack tripping rate sub-model, the shielding failure tripping rate sub-model and the induced lightning tripping rate sub-model in the area to be evaluated;

[0174] The strike-back tripping rate, shielding failure 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 value of the lightning tripping rate of each base tower of the transmission lines in the area to be evaluated, and the lightning risk of the area to be evaluated is evaluated by the average value of the lightning tripping rate.

[0175] In the above technical solution, the specific method of performing parallel calculation based on the set initial potential and the 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 is as follows: Figure 2 As shown, the spatial electric field of the area to be evaluated is divided into n media, and the surface potential of medium 1 is U 1 , the surface potential of medium 2 is U 2 , the surface potential of medium n is U n , it is necessary to calculate the electric field around each medium; the periphery of the medium has an artificial boundary with a set initial potential, the artificial boundary should be located in the air and the artificial boundary can completely surround each medium, so that the coal is in its own closed space. First, assume that the set initial potential of the artificial boundary is 0V, and iteratively calculate the potential inside the artificial boundary according to the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium, then superimpose the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary to obtain the new potential of the artificial boundary, and then use the new potential of the artificial boundary and the internal potential to obtain the actual surface equivalent charge density of the medium, integrate the actual surface equivalent charge density of the medium to all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and use the potential contribution of the medium to all artificial boundaries as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and use the parallel algorithm to obtain the actual potential of each point in the space electric field of the area to be evaluated.

[0176] In the above technical solution, the calculation method of the potential inside the artificial boundary is obtained by iteratively calculating the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium: first, the formula for calculating the set surface equivalent charge density of the corresponding medium according to the set initial potential of the artificial boundary is as follows:

[0177]

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

[0179] Then, the artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows:

[0180]

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

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

[0183] In actual operation, the multi-threaded acceleration method is used to calculate the n media in the space electric field of the area to be evaluated, such as Figure 4 As shown, m PCs are used to participate in the calculation of the n pieces of media (m<n). First, PCs 1-m calculate media 1-m in turn, where each PC performs the following steps to solve the media to be calculated in turn. For example, PC 1 corresponds to calculating medium 1. Step 1: superimpose the potential contribution 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 each point inside the artificial boundary; Step 3: use the obtained (equivalent) surface charge density of the medium in the partition to integrate the artificial boundaries of all partitions to obtain the potential contribution of the medium to all artificial boundaries, and send it to other PCs;

[0184] Secondly, the PC that completes the above three steps first calculates the m+1th medium (similarly, the above three steps are performed on medium m+1), and the second PC that completes the above three steps calculates the m+2th medium, and so on. Each idle computer will continue to calculate the next medium in order until a PC calculates the nth medium, and then the next idle PC will start calculating from medium 1, and the cycle will continue until the converged medium exits the calculation queue, and only the medium that has not yet converged is calculated. Finally, all media converge and the calculation ends.

[0185] In the present invention, a data grouping algorithm is used to respectively calculate the strike-back tripping rate, the shielding tripping rate, and the induced lightning tripping rate of the power transmission line in the area to be evaluated. Although the grouping algorithm can calculate all the data groups with the possibility of lightning data, and improve the accuracy of the calculation, the grouping algorithm increases the computing consumption of the system, and the time-consuming of the grouping calculation can be reduced by multi-threaded acceleration. The grouping calculation can be specifically decomposed into two parts: grouping and calculation. The calculation will cause confusion in the result during the actual test process. The problem is that the context needs to be processed when the CUDA multi-threaded call is judged, so the current multi-threaded acceleration is to accelerate the grouping process. After the loaded original data is divided into tasks, the processing of each task is independent of each other, and multi-threaded task processing can be started from then on. In order to ensure that each thread has exclusive calculation, it is necessary to use a mutex lock to control the accessibility of the calculation near the call calculation interface.

[0186] In the above technical solution, the potential contribution of n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed and calculated to obtain the new potential of the artificial boundary. The calculation formula is as follows:

[0187] U r1 =U 11 +U 21 +…+U n1

[0188] Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is 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 in the space electric field of the area 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: thundercloud and downlink leader model, oncoming leader model and transmission line model, such as Figure 3 As shown, the thundercloud and downlink leader model include a downlink leader channel, a downlink leader flow area and a point to be developed, the oncoming leader model includes an oncoming leader flow area and an oncoming leader channel, and the transmission line model includes poles, lightning conductors and transmission lines.

[0191] In the above technical solution, the calculation formula for establishing the thundercloud and downlink leader model of the area 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a 0 =1.476×10 -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 downward leader channel can be inverted by the return current waveform. If the time when the downward leader reaches the ground is T 0 The time when the first return current wave reaches the bottom of the cloud is T 1 , then when ΔT=T 1 -T 0 The total charge obtained by integrating the return stroke current within the time interval is the total charge of the downward leader channel. The charge distribution of the downward leader channel can be calculated according to the formula proposed by Cooray. In this paper, the average return stroke duration is taken as 100μs.

[0198] Furthermore, by simulating and calculating the thundercloud and the downward leader model of the area to be evaluated, the specific method for obtaining the ground lightning distribution in the area to be evaluated is: using COMSOL simulation software to simulate the development of the lightning downward leader classification, and continuously calculating the position and potential of the potential development point of the lightning downward leader by using the thundercloud and the downward 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 lightning downward leader changes, the simulation of a lightning strike process is completed, and 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 article, the judgment of the transition of the potential development point of the downward leader of lightning is as follows: when the average field strength between the upward and downward leaders or between the downward leader and a target object that has not produced an upward leader (the upward leader refers to a phenomenon caused by a strong electric field on the target object, and the criterion is used to determine whether the target object has produced an upward leader) exceeds the average critical field strength of 500kV / m or the upward and downward leaders meet, the final transition of the lightning strike occurs; the thundercloud potential is set to -200MV; the development step is set to 20m.

[0199] In this paper, the initiation and development process of lightning oncoming leader includes four main stages: initial corona initiation, streamer development, streamer leader transformation and oncoming leader continuous development. Firstly, the surface electric field of lightning conductor and conductor is calculated, and the Peek criterion is used to determine whether the initial corona is initiated. After the initial corona is initiated, the oncoming streamer length and injection current of lightning conductor and conductor are calculated. When the temperature Th at the root of the streamer is greater than 1 500K, the oncoming leader is initiated. The space charge increment generated by the streamer in front of the oncoming leader is calculated according to the distortion of the potential distribution. Finally, the oncoming leader development speed is calculated according to the current injected into the leader head.

[0200] The calculation formula for determining whether the initial corona has started using the Peek criterion is:

[0201]

[0202] In the formula, E c is the corona initiation critical field strength of the lightning rod and conductor (MV / m), m is the roughness coefficient and is taken as 0.9, δ is the relative air density and is taken as 1.0, r c is the radius of the lightning conductor and the sub-conductor. When the average field strength is greater than the critical field strength E c When , it is determined that the initial corona starts.

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

[0204]

[0205] E=(UE zx) / (Dx)

[0206] Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the continuous development of the leader energy, and E is the residual gap electric field strength.

[0207] In the above technical scheme, the specific method of establishing a transmission line model using the actual potential of each point in the spatial electric field is: dividing the lightning rod, the conductor and the tower into cylindrical conductor elements, controlling the boundary potential of the cylindrical conductor elements, and calculating the open-domain dynamic three-dimensional electric field of the transmission line during the development of the downstream leader, thereby obtaining a transmission line model.

[0208] To calculate the counter-tripping rate, we first need to calculate the counter-tripping level of the transmission line. The calculation formula is as follows:

[0209]

[0210] Where I is the lightning resistance level of the line tower, U 50％ is the 50% impulse flashover voltage of the insulator, k is the coupling coefficient considering the impact of the impulse corona, h t is the average height of the conductor above the ground, h g is the average height of the lightning conductor above the ground, β is the tower current shunt coefficient, R i is the tower impulse grounding resistance, h a is the cross arm height, h c is the height of the conductor to the ground, L t is the total inductance of the tower, k 0 is 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 obtained based on the lightning resistance level of the line lightning tower. I , P I The calculation formula is as follows:

[0212]

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

[0214] P f =N×g×P I ×η

[0215]

[0216] Where P f is the strike-back tripping rate, N is the total number of lightning strikes in the area to be evaluated, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between the two lightning conductors, and h is the height of the lightning conductor above the ground.

[0217] The maximum lightning strike current of the line is calculated according to the electrical geometry model method, and then the shielding trip rate of the line is calculated according to the exposure distance method. The shielding trip rate of the transmission line is calculated to obtain the shielding trip rate sub-model. In the above technical solution, the calculation formula of the shielding trip rate sub-model is as follows:

[0218]

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

[0220] Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, l BD is the lightning exposure width, f(I) is the lightning current probability density function, r max is the maximum impact distance.

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

[0222]

[0223]

[0224] y max =25H C I / U 50％

[0225]

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

[0227] In the above technical solution, the back-stroke tripping rate, shielding failure tripping rate, and induced lightning tripping 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 tripping rate of each pole tower of the transmission line in the area to be evaluated is as follows:

[0228]

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

[0230] The data grouping algorithm is used to calculate the back-stroke tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission line in the area to be evaluated respectively. Dividing into small groups can perform a full permutation of the real data, and finally send the arranged data to the calculation interface to obtain the calculation result. Dividing into large groups adopts the form of iterative matching, performs triangular matching on the data under each station, and calculates all possible data groups of the existing 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 tripping rate is as follows: when m < 0.5S, it is considered that the lightning risk level of the pole 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 pole 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 pole 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 pole towers in each area of the complex terrain is level IV, and level IV is an extremely high risk.

[0232] Embodiment 3

[0233] The third aspect of the present invention proposes a computer-readable storage medium, which stores a computer program, and when the computer program is executed by a processor, it implements the steps of the above method.

[0234] Embodiment 4

[0235] In a distributed network parallel programming environment based on MIP, a waveguide closed matrix region formed by PML as the truncation boundary in the electromagnetic field is modeled to solve its field intensity distribution. A large-scale linear equation is obtained through the finite element method and solved using a parallel algorithm.

[0236] In order to compare whether the solution vectors finally obtained by the serial and parallel algorithms are consistent, the same error tolerance is taken. The serial and parallel algorithms are used to solve the problems 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 Serial and parallel acceleration test results

[0238] Iteration steps Run time(s) Speedup 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 iterations, which is due to the impact of calculation accuracy. The running time is reduced, and the parallel implementation does not change the basic performance of the algorithm.

[0240] Then, we take the same number of iterations to test the execution time of the serial and parallel algorithms, and test the speedup ratio and parallel efficiency that reflect the parallel performance. The results are shown in Table 2.

[0241] Table 2 Serial and parallel acceleration test results under the same number of iterations

[0242]

[0243] From Table 1 and Table 2, we can see that the parallel operation takes less time than the serial operation. When the serial program is running, only one process is started, while the parallel program can start multiple processes. Windows is a multi-tasking operating system, which means that the utilization probability obtained by running the parallel program is approximately n times that of the serial program, which improves the single-machine utilization and thus improves the parallel performance.

[0244] The present invention calculates the spatial field potential in the downlink leader channel in parallel through a multithreaded acceleration method, and judges the downlink development point according to its potential, then calculates the ground lightning density in the area to be evaluated, and respectively obtains the counter-attack tripping rate model, the shielding tripping rate model and the induced lightning tripping rate model of the transmission line by using the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, and then respectively calculates the actual values ​​of the three tripping rates of the counter-attack tripping rate, the shielding tripping rate and the induced lightning tripping rate according to the obtained ground lightning density in the area to be evaluated, and obtains the average value of the lightning tripping rate of each base tower of the transmission line in the area to be evaluated according to the sum of the three tripping rates, and then uses the average value of the lightning tripping rate to evaluate the lightning strike risk. The present invention effectively combines the multithreaded acceleration method and the data grouping algorithm, while ensuring the accuracy of the data, improving the data calculation efficiency, so that the lightning strike risk assessment result can be obtained in a shorter time, thereby providing real-time data support for the implementation of lightning protection measures, and improving the lightning protection capability and operation safety of the power system.

[0245] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer storage media. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer storage medium implemented in one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program codes.

[0246] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer storage media according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A system that specifies the functions of a box or multiple boxes.

[0247] These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory produce a product including an instruction system, which is implemented in the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0248] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified 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 rather than to limit its protection scope. Although the present invention has been described in detail with reference to the above embodiments, ordinary technicians in the field should understand that after reading the present invention, those skilled in the art can still make various changes, modifications or equivalent substitutions to the specific implementation methods of the invention, but these changes, modifications or equivalent substitutions are all within the protection scope of the pending claims of the invention.

[0250] The contents not described in detail in this specification belong to the prior art known to professional and technical personnel in this field.

Claims

1. A transmission line lightning risk accelerated assessment system, characterized in that: include: A ground lightning distribution module is used to perform parallel calculations based on the set initial potential and the 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, to use the actual potential of each point in the space electric field to respectively establish a thundercloud and a downward leader model, an oncoming leader model and a transmission line model of the area to be evaluated, and to obtain the ground lightning distribution of the area to be evaluated by simulating and calculating the thundercloud and the downward leader model of the area to be evaluated; A trip rate grouping calculation module is used to obtain the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model of the transmission line in the area to be evaluated according to the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, respectively, and take the ground lightning distribution in the area to be evaluated as the ground lightning density, and calculate the counter-attack trip rate, shielding failure trip rate and induced lightning trip rate of the transmission line in the area to be evaluated according to the ground lightning density and the counter-attack trip rate sub-model, the shielding failure trip rate sub-model and the induced lightning trip rate sub-model in the area to be evaluated; The lightning strike risk assessment module is used to combine and calculate the counter-strike tripping rate, shielding failure tripping rate, and induced lightning tripping rate of the transmission lines in the area to be assessed, obtain the average value of the lightning strike tripping rate of each base tower of the transmission lines in the area to be assessed, and assess the lightning strike risk of the area to be assessed through the average value of the lightning strike tripping rate.

2. The transmission line lightning risk accelerated assessment system according to claim 1, characterized in that: The specific method of performing parallel calculation according to the set initial potential and the 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 is as follows: the space electric field of the area to be evaluated is divided into n media, and the outer periphery of the medium has an artificial boundary with a set initial potential, and the potential inside the artificial boundary is obtained by iterative calculation according to the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium, and the potential contribution of the n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed to obtain the new potential of the artificial boundary, and the actual surface equivalent charge density of the medium is obtained by using the new potential of the artificial boundary and the internal potential, and the actual surface equivalent charge density of the medium is integrated for all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and the potential contribution of the medium to all artificial boundaries is used as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and the actual potential of each point in the space electric field of the area to be evaluated is obtained by parallel calculation.

3. The transmission line lightning risk accelerated assessment system according to claim 2, characterized in that: The calculation method of 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 medium: The formula for calculating the set surface equivalent charge density of the corresponding medium based on the set initial potential of the artificial boundary is as follows: In the formula, σ is the set surface equivalent charge density of the corresponding medium, ε is the relative dielectric constant, Set the initial potential for the artificial boundary, is a variable, e n is the normal unit vector of the interface; The artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows: In the formula, is the new artificial boundary potential, σ is the surface charge density of the conductor, ρ is the known volume charge density, R is the radius of the charged conductor, σ P is the surface polarization charge density, S′ is the conductor surface, S″ is the interface between the two dielectrics, and V′ is the conductor volume; Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until the potential inside the artificial boundary is obtained.

4. The transmission line lightning risk accelerated assessment system according to claim 3, 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) Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is the potential contribution of medium n to the artificial boundary.

5. The transmission line lightning risk accelerated assessment system according to claim 4, characterized in that: The specific method for establishing the thundercloud and downward leader model, upward leader model, and 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a0=1.476×10 -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 upward 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) Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the leader to continue to develop, and E is the residual gap electric field strength; 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.

6. The transmission line lightning risk accelerated assessment system 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: 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 ground lightning strike distribution of the mesoscopic terrain.

7. The transmission line lightning risk accelerated assessment system according to claim 6, characterized in that: The calculation formula for the backflashover rate sub-model is as follows: P f =N×g×P I × η (12) Where P f is the strike-back tripping rate, N is the total number of lightning strikes in the area to be assessed, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between two lightning conductors, and h is the height of the lightning conductor above the ground; The calculation formula for the shielding failure rate sub-model is as follows: f(I)=I max (0.1r max ) 1.54 (15) Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, l BD is the lightning exposure width, f(I) is the lightning current probability density function, r max is the maximum impact distance; The calculation formula for the induced lightning flashover rate sub-model is as follows: y max =25H C I / U 50％ (18) Where P g is the induced lightning trip rate, D k is the distance from the direct hit point to the line, r c is the conductor striking distance, r g is the earth strike distance, H C y is the distance between the tower conductor suspension point and the ground, max is the flashover range of induced lightning, I is the induced lightning current, U 50％ Insulator string 50% impulse flashover voltage, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, η is the arcing rate, η=0.4, I C is the lightning current amplitude, and P(I) is the lightning current amplitude distribution probability function.

8. The transmission line lightning risk accelerated assessment system according to claim 7, characterized in that: The calculation formula for obtaining the average value of the lightning flashover rates of each tower of the transmission line in the area to be evaluated by combining and calculating the backflashover 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 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 flashover rate of the tower, m is the sum of the backflashover 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 through 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.

9. A method for accelerating the assessment of lightning strike risk of power transmission lines, characterized in that: Including: According to the set initial potential and the set surface equivalent charge density of each point in the space electric field of the area to be evaluated, parallel calculation is performed to obtain the actual potential of each point in the space electric field of the area to be evaluated, and the thundercloud and downlink leader model, the oncoming leader model and the transmission line model of the area to be evaluated are respectively established by using the actual potential of each point in the space electric field, and the ground lightning distribution in the area to be evaluated is obtained by simulating the thundercloud and downlink leader model of the area to be evaluated; According to the thundercloud and the downlink leader model, the oncoming leader model and the transmission line model, respectively obtain the counter-attack tripping rate sub-model, the shielding failure tripping rate sub-model and the induced lightning tripping rate sub-model of the transmission line in the area to be evaluated, take the ground lightning distribution in the area to be evaluated as the ground lightning density, and respectively calculate the counter-attack tripping rate, shielding failure tripping rate and induced lightning tripping rate of the transmission line in the area to be evaluated according to the ground lightning density and the counter-attack tripping rate sub-model, the shielding failure tripping rate sub-model and the induced lightning tripping rate sub-model in the area to be evaluated; The strike-back tripping rate, shielding failure 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 value of the lightning tripping rate of each base tower of the transmission lines in the area to be evaluated, and the lightning risk of the area to be evaluated is evaluated by the average value of the lightning tripping rate.

10. The method for accelerating assessment of lightning strike risk of power transmission lines according to claim 9, characterized in that: The specific method of performing parallel calculation according to the set initial potential and the 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 is as follows: the space electric field of the area to be evaluated is divided into n media, and the outer periphery of the medium has an artificial boundary with a set initial potential, and the potential inside the artificial boundary is obtained by iterative calculation according to the set initial potential of the artificial boundary and the set surface equivalent charge density of the corresponding medium, and the potential contribution of the n media in the space electric field of the area to be evaluated to the artificial boundary is superimposed to obtain the new potential of the artificial boundary, and the actual surface equivalent charge density of the medium is obtained by using the new potential of the artificial boundary and the internal potential, and the actual surface equivalent charge density of the medium is integrated for all artificial boundaries in the space electric field of the area to be evaluated to obtain the potential contribution of the medium to all artificial boundaries, and the potential contribution of the medium to all artificial boundaries is used as the actual potential of the corresponding point of the medium in the space electric field of the area to be evaluated, and the actual potential of each point in the space electric field of the area to be evaluated is obtained by parallel calculation.

11. The method for accelerating assessment of lightning strike risk of power transmission lines according to claim 10, characterized in that: The calculation method of 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 medium: The formula for calculating the set surface equivalent charge density of the corresponding medium based on the set initial potential of the artificial boundary is as follows: In the formula, σ is the set surface equivalent charge density of the corresponding medium, ε is the relative dielectric constant, Set the initial potential for the artificial boundary, is a variable, e n is the normal unit vector of the interface; The artificial boundary is integrated using the set surface equivalent charge density of the corresponding medium to obtain the new artificial boundary potential, which is calculated as follows: In the formula, is the new artificial boundary potential, σ is the surface charge density of the conductor, ρ is the known volume charge density, R is the radius of the charged conductor, σ P is the surface polarization charge density, S′ is the conductor surface, S″ is the interface between the two dielectrics, and V′ is the conductor volume; Substitute the new artificial boundary potential into formulas (1) and (2) and iterate until the potential inside the artificial boundary is obtained.

12. The method for accelerating assessment of lightning strike risk of power 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) Where U r1 is the new potential of the artificial boundary, U 11 is the potential contribution of medium 1 to the artificial boundary, U 21 is the potential contribution of medium 2 to the artificial boundary, U n1 is the potential contribution of medium n to the artificial boundary.

13. The method for accelerating assessment of lightning strike risk of power transmission lines according to claim 12, characterized in that: The specific method for establishing the thundercloud and downward leader model, upward leader model, and 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) is the charge density of the leader channel C / m, ζ is the leader channel length, H c is the height of thundercloud, z is the height of the descending leader head above the ground, I P is the return current amplitude kA, and the coefficient is a0=1.476×10 -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 upward 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) Where U lc is the starting voltage of the continuous leader, h is the height of the grounding electrode, d is the distance between the lower leader head and the target, v is the leader development speed, k is the leader speed development coefficient, U is the voltage on the gap, D is the gap length, x is the length of the leader that has been developed, and E Z is the electric field strength of the pilot channel, E l0 is the minimum electric field strength for the leader to continue to develop, and E is the residual gap electric field strength; 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 method for accelerating assessment of lightning strike risk of power 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 performing simulation calculations on 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 points of the lightning downward leader. When the potential development points of the lightning downward leader undergo a jump, a simulation of a lightning strike process 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 method for accelerating assessment of lightning strike risk of power 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) Where P f is the strike-back tripping rate, N is the total number of lightning strikes in the area to be assessed, g is the pole striking rate, which is 1 / 6 in plains and 1 / 4 in mountainous areas, and P I is the probability of a lightning current greater than I, η is the arcing rate, η=0.4, N g is the density of ground lightning in each area of ​​the terrain to be evaluated, b is the distance between two lightning conductors, and h is the height of the lightning conductor above the ground; The calculation formula for the shielding failure flashover rate sub-model is as follows: f(I)=I max (0.1r max ) 1.54 (15) Where P r is the interruption tripping rate, η is the arcing rate, η=0.4, ΔL is the collector line section with a length of ΔL, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, I max is the maximum current amplitude of the shielding flashover, I C is the lightning current amplitude, l BD is the lightning exposure width, f(I) is the lightning current probability density function, r max is the maximum impact distance; The calculation formula for the induced lightning flashover rate sub-model is as follows: y max =25H C I / U 50％ (18) Where P g is the induced lightning trip rate, D k is the distance from the direct hit point to the line, r c is the conductor striking distance, r g is the earth strike distance, H C y is the distance between the tower conductor suspension point and the ground, max is the flashover range of induced lightning, I is the induced lightning current, U 50％ Insulator string 50% impulse flashover voltage, N g is the density of ground-to-ground lightning in each area of ​​the terrain to be evaluated, η is the arcing rate, η=0.4, I C is the lightning current amplitude, and P(I) is the lightning current amplitude distribution probability function.

16. The method for accelerating assessment of lightning strike risk of power 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 flashover 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 of the entire transmission line, m is the theoretically calculated lightning flashover rate of the tower, m is the sum of the back flashover rate, shielding failure flashover 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 a processor, it implements the steps of the method described in any one of claims 9-16.

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