TLM-based multi-branch conductor cluster transient response method and system for conductive structures

Abstract

The present invention relates to the field of transient response technology in a near-field environment, and in particular to a TLM-based multi-branch conductor cluster transient response method and system for a conductive structure. The TLM-based multi-branch conductor cluster transient response method for a conductive structure proposed in the present invention numerically divides the conductive structure into a grid, and forms a square coaxial structure with the conductor and the grid surface. At the same time, considering the influence of the metal grid structure on the transient response, a multi-branch node is introduced, which can not only realize the connection of conductors or conductive structures from different directions, but also be suitable for modeling actual engineering structures such as grounding grids or reinforced concrete structures, and can also add lumped elements in series or in parallel to the conductor as the terminal conditions of the conductor. The use of this method can not only retain the full-wave calculation of the spatial transient electromagnetic pulse and the induction component of the non-electrically connected conductor or conductive structure loop, but also greatly reduce the grid requirements, thereby reducing memory usage and improving computing efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of transient response in a near-field environment, and in particular to a TLM (transmission line modeling)-based multi-branch conductor cluster transient response method and system for a conductive structure. Background Art

[0002] When performing large-scale electromagnetic field calculations, the object often contains conductors whose radial dimensions are much smaller than the wavelength of the target frequency. This type of conductor is called a thin conductor. When solving the transient response of a thin conductor in full-wave, it is necessary to divide the grid on its cross section. Since the radial dimensions of a thin conductor are small, the overall target grid size will be compromised to that of the thin conductor. In this case, analyzing multiple thin conductor structures arranged in a larger electromagnetic structure will lead to unnecessary grid redundancy in electromagnetic transient analysis, resulting in excessive memory usage and a significant increase in calculation time.

[0003] In the past, for such problems, local refined meshing technology is usually used, or transmission line equivalent solution is adopted, or the entire conductor structure is equivalent to a rational function model using the vector matching method, and then converted into a lumped impedance model for solution. However, the local refinement method consumes a lot of computing resources, the transmission line method cannot be equivalent to a complex conductor reinforcement network, and the vector matching method is not flexible enough when facing actual engineering. Therefore, a fast and accurate calculation method is urgently needed for the transient response calculation of thin conductors under complex structures. Summary of the invention

[0004] In order to overcome the defect of the above-mentioned prior art that it is difficult to quickly and accurately calculate the transient response of complex structures, the present invention proposes a TLM-based multi-branch conductor cluster transient response method for conductive structures, which realizes the rapid calculation of the response between non-electrically connected thin conductor loops.

[0005] The present invention proposes a TLM-based multi-branch conductor cluster transient response method for a conductive structure, comprising the following steps:

[0006] S1. The research object is divided into conductor nodes through a hexahedral grid, and thin conductors are arranged in the hexahedral grid to construct a conductor cluster model corresponding to the conductor node; the conductor cluster model is composed of thin conductors arranged in three directions (x, y, z) of the Cartesian coordinate system, and the thin conductors cross at the center of the hexahedral grid to form six branches extending outward from the intersection of the thin conductors; the hexahedral grid adopts a cubic structure, and the side length of the hexahedral grid is greater than the cross-sectional diameter of the conductor node; the research object is a conductive structure;

[0007] S2. Construct the response calculation formula of a single conductor node. The response includes the current {I ch|1≤h≤6} and the voltage V at the conductor node c ;

[0008] S3, construct the response propagation equation of the conductor node;

[0009] S4, determining the topological structure of the conductor nodes on the conductive structure, determining the excitation input point and the response observation point, and obtaining the propagation path from the excitation input point to the response observation point;

[0010] S5. Starting from the excitation point on the propagation path, the responses of adjacent conductor nodes are calculated in sequence until the response of the response observation point is obtained.

[0011] Preferably, let branch m and branch g have the same direction, and branch m is in the positive direction of Q, and branch g is in the negative direction of Q, Q∈{x,y,z}, then the propagation equation in the Q direction in S3 is:

[0012] t+1 V i c0g (q-1)= t V r c0m (q)F bm ; t+1 V i c0m (q+1)= t V r c0g (q)F bg ;

[0013] t+1 V i csm (q)= t V r csm (q)(-F bm ); t+1 V i csg (q)= t V r csg (q)(-F bg );

[0014] t+1 V i com (q)= t V r com (q)F bm ; t+1 V i cog (q)= t V r cog (q)Fbg ;

[0015] Where t represents the moment, t+1 represents the next moment of t; superscript i represents the incident voltage, superscript r represents the reflected voltage; q-1, q and q+1 are continuous conductor nodes distributed along the positive direction of Q; t+1 V i c0g (q-1) represents the incident voltage pulse matrix V of the conductor node q-1 on the branch g at time t+1 i c0g , t+1 V i c0m (q+1) represents the incident voltage pulse matrix V of conductor node q+1 on branch m at time t+1 i c0m ; V r c0m represents the reflected voltage pulse matrix of branch m, t V r c0m (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch m at time t r c0m ; t V r c0g (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch g at time t r c0g ;

[0016] t+1 V i csm (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch m at time t+1 i csm , t+1 V i csg (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch g at time t+1 i csm ; t V r csm (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch m at time t r csm , t V r csg (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch g at time t r csg ;

[0017] t+1V i com (q) represents the open circuit compensation voltage V generated by the incident pulse at the conductor node q at time t+1 on branch m i com , t+1 V i cog (q) represents the open circuit compensation voltage V generated by the incident pulse on the branch g at the conductor node q at time t+1 i cog ; t V r com (q) represents the open circuit compensation reflected voltage matrix V of the branch m at the conductor node q at time t r com , t V r cog (q) represents the open circuit compensation reflected voltage matrix V of the branch g at the conductor node q at time t r cog ;

[0018] F bm is the sign of branch m; F bm When the value is "1", it means that branch m exists. bm The value is "0" means that branch m does not exist; F bg is the sign of branch g; F bg When the value is "1", it means that branch g exists. bg A value of "0" indicates that branch g does not exist.

[0019] Preferably, in S2, the calculation formula of the response is:

[0020] I cm =Y c∑sm V c∑sm -Y c∑sm V c ;-I cg =Y c∑sg V c∑sg -Y c∑sg V c ;

[0021] V c = N h / D h ; N h =F bh (Y c∑sh V c∑sh -I c∑oh );

[0022] D h =Fbh [Y c∑oh +Y c∑sh ((k+1)I k,k -[1] k,k )]; Y c∑sh =(Z coh +Z csh,const +R csh +Z th,const ) -1 ;

[0023] Y c∑oh =Y coh,const +G coh +Y th,const ;

[0024] V c∑sh =2V i c0h -2V i csh [1] k,1 -V n csh,freq [1] k,1 -V n th,freq [1] k,1 + V th +[V z / 2]F m ;

[0025] I c∑oh =-2Y coh,const (V i coh [1] k,1 )+I n coh,freq [1] k,1 +I n th,freq [1] k,1 -I th [1] k,1 ;

[0026] Among them, I cm represents the current in branch m, Y c∑sm It represents the integrated short-circuit compensation admittance corresponding to branch m, V c∑sm I represents the integrated short-circuit compensation voltage corresponding to branch m; cg represents the current in branch g, Y c∑sg It represents the integrated short-circuit compensation admittance corresponding to branch g, V c∑sg It represents the integrated amount of short-circuit compensation voltage corresponding to branch g;

[0027] V c represents the total voltage matrix of the conductor cluster nodes; Nh and D h Both represent the integration amount corresponding to branch h in the case of multiple cores; Y c∑sh It represents the integrated short-circuit compensation admittance corresponding to branch h, V c∑sh It represents the integrated short-circuit compensation voltage corresponding to branch h, I c∑oh Indicates the integrated amount of open circuit compensation current corresponding to branch h, Y c∑oh represents the integrated open-circuit compensation admittance corresponding to branch h; [1] k,k

[0028] represent k × k A matrix with dimensions whose elements are all 1; [1] k,1 represent k × 1 dimensional matrix whose elements are all 1; k,k represents the k-order identity matrix;

[0029] Z coh represents the open circuit compensation impedance of branch h, Z csh Represents the short-circuit compensation impedance of branch h, Z csh,const Represents Z csh The constant term in the expression, R csh Represents the short-circuit compensation resistance of branch h, Z th is the load impedance of the terminal series-parallel connection of branch h, Z th,const Represents Z th The constant term in the expression; Y coh is the open circuit compensation admittance on branch h, Y coh,const Y coh The constant term in G coh Y represents the equivalent conductance of the parallel electric field loss of branch h; th is the load admittance on branch h, Y th,const Y th Constant terms in expressions;

[0030] V i c0h represents the incident voltage pulse matrix of branch h, V i csh represents the incident voltage pulse matrix for short-circuit compensation of branch h, [1] k,1 represents a k×1 1 matrix, V n csh,freq Represents the voltage generated by the frequency-dependent term of the short-circuit compensation impedance on the upper branch h at time n, V n th,freq represents the voltage generated by the frequency-dependent term of the load impedance on the upper branch h at time n, V th is the series excitation voltage source of branch h, V zrepresents the equivalent source of the instantaneous incident electric field at the node of the conductor external medium in the z direction, F m Indicates shielding sign. When the thin conductor is not affected by transient electromagnetic pulses, F m =0; otherwise F m =1;

[0031] V i coh represents the open circuit compensation voltage on branch h caused by the incident pulse, I n coh,freq represents the current related to the frequency-dependent term of the open-circuit compensation admittance on the upper branch h at time n, I n th,freq represents the current generated by the frequency-dependent term of the load impedance on branch h, I th Represents the load current in series and parallel at the terminals of branch h.

[0032] Preferably, V n csh,freq 、V n th,freq ,I n coh,freq ,I n th,freq The calculation formula is as follows:

[0033] Z csh I ch =Z csh,const I ch +V n csh,freq [1] k,1 ; Z th I ch =Z th,const I ch +V n th,freq [1] k,1 ;

[0034] Y coh [(V coh -2V i coh )[1] k,1 ]=Y coh,const [(V coh -2V i coh )[1] k,1 ]+I n coh,freq [1] k,1 ;

[0035] Y th (V coh [1] k,1 )= Y th,const (V coh [1] k,1 )+I n th,freq [1] k,1 ;

[0036] in, represents convolution; Z csh Represents the short-circuit compensation impedance of branch h, Z csh,const Represents Z csh Constant term in an expression; I ch represents the current on the branch h of the conductor node; Z th is the load impedance of the terminal series-parallel connection of branch h, Z th,const Represents Z th Constant terms in expressions;

[0037] Y coh is the open circuit compensation admittance on branch h, Y coh,const Y coh The constant term in V coh Represents the instantaneous port voltage of branch h; V i coh represents the open circuit compensation voltage on branch h generated by the incident pulse;

[0038] Y th is the load admittance on branch h, Y th,const Y th A constant term in an expression.

[0039] Preferably, step S5 comprises the following sub-steps:

[0040] S51, obtaining the reference parameters of the conductor node q, and substituting the known reference parameters of the conductor node q at time t into the propagation equation to calculate the solution parameters of the next conductor node q' at time t+1 on the propagation path; the initial value of q is the excitation input point, and the initial value of t is the excitation pulse input time;

[0041] Reference parameters include: the reflected voltage pulse matrix V of branch h r c0h , short-circuit compensation reflected voltage pulse matrix of branch h

[0042] V r csh , open circuit compensation reflected voltage matrix V of branch h r coh ;

[0043] The solution parameters include: the incident voltage pulse matrix V of branch h i c0h , short-circuit compensation incident voltage pulse matrix of branch h

[0044] V i csh , branch h is the open circuit compensation voltage V generated by the incident pulse i coh ;

[0045] S52, determine whether the conductor node q' is a response observation point: if yes, calculate the current {I cm |1≤m≤6} and its voltage V c ; No, execute step S53;

[0046] S53, calculating reference parameters of conductor node q';

[0047] V r c0m =(V i c0m -Z c0m I cm )F bm ; V r c0g =(V i c0g +Z c0g I cg )F bg ;

[0048] V r csm =(V i csm +Z csm I cm )F bm ; V r csg =(V i csg +Z csg I cg )F bg ;

[0049] V r com =(V com -V i com )F bm ; V r cog =(V cog -V i cog )F bg ;

[0050] Among them, V i c0m represents the incident voltage pulse matrix of branch m, Z c0m represents the characteristic impedance of branch m, I cm represents the current in branch m, F bm Indicates the sign of branch m; V i c0g represents the incident voltage pulse matrix of branch g, Z c0g represents the characteristic impedance of branch g, I cg represents the current in branch g, F bg Indicates the sign of branch g; V i csm represents the short-circuit compensation incident voltage pulse matrix of branch m, Z csm Represents the short-circuit compensation characteristic impedance of branch m; V com Represents the instantaneous port voltage of branch m; V i com V represents the open circuit compensation voltage generated by the incident pulse in branch m; i csg The short-circuit compensation incident voltage pulse moment of branch g is

[0051] Array, Z csg Represents the short-circuit compensation characteristic impedance of branch g; V cog Represents the instantaneous port voltage of branch g; V i cog It represents the open circuit compensation voltage generated by the incident pulse in branch g; branch m is collinear with branch g, and branch m is in the forward direction and branch g is in the reverse direction;

[0052] S54, update q to q', update t to t+1; then return to step S51.

[0053] Preferably, let the instantaneous port voltage of branch h be V coh Preferably, let the instantaneous port voltage of branch h be V coh ;

[0054] ;

[0055] V c pk =∑ 6 h=1 (V c,h pp -V c,h kk );

[0056] Among them, V c,h pp is the voltage of conductor p on branch h in the conductor cluster node, V c,hkk is the voltage of conductor k on branch h in the conductor cluster node; V c pk and V c kp Both represent the differential mode voltage between conductor p and conductor k in the conductor cluster node, 1≤k≤K0, 1≤p≤K0, and p≠k, K0 is the number of parallel conductors in the conductor node.

[0057] Preferably, the load current of the terminal series-parallel connection of branch h is denoted as I th , the load admittance on branch h is denoted as Y th , the open circuit compensation admittance on branch h is recorded as Y coh The equivalent conductance of the parallel electric field loss of branch h is denoted as G coh ,have:

[0058] ;

[0059] ;

[0060] Among them, I th kk is the parallel terminal current source of conductor k on branch h, I th pk Y is the parallel terminal current source generated by the conductor k under the influence of the conductor p on the branch h; th kk is the terminal admittance of conductor k on branch h, Y th pk is the terminal admittance generated by conductor k under the influence of conductor p on branch h; Y coh kk represents the open circuit compensation admittance of conductor k on branch h, Y coh pk Represents the conductor on branch h

[0061] The open circuit compensation admittance generated by conductor k under the influence of p; G coh kk represents the open-circuit additional conductance of conductor k on branch h; G coh pk It represents the additional open-circuit conductance of the conductor k under the influence of the conductor p on the branch h.

[0062] Preferably, in the equivalent circuit of a multi-core cable composed of the same cores, there are:

[0063] I th pk =I th kp, Y th pk =Y th kp ; Y coh pk = Y coh kp , G coh pk = G coh kp ;

[0064] Among them, I th kp Y is the parallel terminal current source generated by the conductor p under the influence of the conductor k on the branch h; th kp is the terminal admittance of conductor p under the influence of conductor k on branch h; Y coh kp represents the open circuit compensation admittance generated by conductor p on branch h under the influence of conductor k; G coh kp It represents the additional open-circuit conductance of the conductor p caused by the influence of the conductor k on the branch h.

[0065] Preferably, the hexahedral grid adopts a cubic structure, and the side length of the hexahedral grid is greater than or equal to 10 times the cross-sectional diameter at the conductor node.

[0066] The present invention proposes a TLM-based multi-branch conductor cluster transient response system for a conductive structure, comprising a memory and a processor, wherein a computer program is stored in the memory, and the processor is connected to the memory, and the processor is used to execute the computer program to implement the TLM-based multi-branch conductor cluster transient response method for a conductive structure.

[0067] The advantages of the present invention are:

[0068] The TLM-based multi-branch conductor cluster transient response method for conductive structures proposed in the present invention numerically divides the conductive structure into hexahedral grids, and forms a square coaxial structure with the conductor and the surface of the hexahedral grid. At the same time, considering the influence of the grid structure on the transient response, the introduction of multi-branch nodes can not only realize the connection of conductors from different directions, but also be suitable for modeling actual engineering structures such as grounding grids or reinforced concrete structures. It is also possible to add lumped elements in series or parallel to the conductors as terminal conditions of the conductors. This method can retain the use of the full-wave method to calculate the spatial transient electromagnetic pulses and induction components of non-electrically connected conductors or cable loops, and can also greatly reduce the grid requirements, thereby reducing memory usage and improving computational efficiency.

[0069] In the present invention, calculation is performed point by point along the response propagation direction starting from the excitation point until the response of the response observation point is obtained, thereby ensuring the accuracy of the response calculation. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] FIG1( a ) is a structural diagram of a conductor cluster model divided by a hexahedral mesh;

[0071] Figure 1(b) is a simplified schematic diagram of the conductor cluster model;

[0072] Figure 2 is a flow chart of a TLM-based multi-branch conductor cluster transient response method for a conductive structure;

[0073] Figure 3 The equivalent circuit of the thin conductor corresponding to the two-core cable;

[0074] Figure 4 For metal grid display;

[0075] Figure 5(a) shows Figure 4 The middle part shows the grid structure;

[0076] FIG5( b ) is a cross-sectional view of the structure of FIG5( a ) in a hexahedral grid;

[0077] Figure 6 This is a schematic diagram of the test system connection in the embodiment;

[0078] Figure 7 The experimental results in the examples are compared with the calculated results. DETAILED DESCRIPTION

[0079] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0080] In this embodiment, a method for modeling a conductive structure is proposed. First, a hexahedral grid is used to divide the conductive structure into multiple conductor nodes, and then a conductor cluster model is established for each conductor node. Referring to Figures 1(a) and 1(b), thin conductors are arranged in a hexahedral grid for the conductor nodes to be calculated to construct a conductor cluster model. Assume that thin conductors are arranged in three directions (x, y, z) of a Cartesian coordinate system, and a hexahedral grid is used for division in the entire space and the thin conductor passes through the center of the dielectric grid. The four surfaces in the surface layer of the hexahedral grid parallel to a thin conductor are designated as the zero potential reference plane of the thin conductor, and the voltage of the thin conductor is defined. Vc is the potential difference between the thin conductor and the zero potential reference plane; the potential difference between the thin conductor and all its zero potential reference planes is equal, so when calculating the potential difference, there is no need to consider the difference in zero potential reference planes.

[0081] Considering the positive and negative directions, the conductor cluster model contains six branches, that is, six branches extending outward from the intersection of the thin conductors. A single hexahedral mesh is regarded as a node. The six branches corresponding to the conductor cluster model in the hexahedral mesh are connected at the center of the node. The hexahedral mesh and the six branches are collectively called the conductor cluster node. b1 、F b2 、F b3 、F b4 、F b5 、F b6} as the existence mark of the six branches, let F bh The corresponding branch is denoted as branch h, 1≤h≤6; F b1 When the value is "1", it means that branch 1 exists. b1 The value is "0" means that branch 1 does not exist; and so on. b2 To F b6 ; That is, F bh When the value is "1", it means that branch h exists. bh A value of "0" indicates that branch h does not exist.

[0082] In the conductor cluster node, branch 1 and branch 2 are collinear and have currents in the same direction, branch 3 and branch 4 are collinear and have currents in the same direction, and branch 5 and branch 6 are collinear and have currents in the same direction.

[0083] In this way, a complex structure composed of thin conductors with arbitrary branch combinations can be realized through branch collection. In a multi-branch conductor cluster node, the node voltage of each branch is the same, and the current on each branch satisfies Kirchhoff's current constraint:

[0084] F b1 × I c1 +F b3 × I c3 +F b5 × I c5 =F b2 × I c2 +F b4 × I c4 +F b6 × I c6

[0085] Vc = V c1 = V c2 = V c3 = V c4 = V c5 = V c6

[0086] in, I c1 represents the current in branch 1, I c2 represents the current in branch 2, I c3 represents the current in branch 3, I c4 represents the current of branch 4, I c5 represents the current in branch 5, I c6 represents the current of branch 6; V c1 represents the voltage of branch 1, V c2 represents the voltage of branch 2, V c3 represents the voltage of branch 3, V c4 represents the voltage of branch 4, V c5 represents the voltage of branch 5, V c6 represents the voltage of branch 6; V c Represents the voltage of the branch.

[0087] There are two types of conductive structures: one is a conductive structure built by a single conductor, such as a single-core cable; the other is a conductive structure built by parallel conductors, such as a multi-core cable.

[0088] For the second conductive structure, the thin conductor is composed of multiple parallel conductors. As shown in FIG1(b), the thin conductor in each direction is composed of two conductor segments corresponding to different branches. In this embodiment, the equivalent circuit of the conductor cluster model is constructed by combining the simplified schematic diagram of the conductor cluster node shown in FIG1(b) and the number of conductors included in the conductive structure.

[0089] Reference Figure 2 The present embodiment proposes a TLM-based multi-branch conductor cluster transient response method for a conductive structure, which includes the following steps S1-S5.

[0090] S1. The research object is divided into conductor nodes through a hexahedral grid. Thin conductors are arranged in the hexahedral grid to construct a conductor cluster model corresponding to the conductor node. The conductor cluster model is composed of thin conductors arranged in three directions (x, y, z) of the Cartesian coordinate system, and the thin conductors cross at the center of the hexahedral grid. The conductor model is divided into six branches extending outward from the intersection of the thin conductors. The branch set {F b1 、F b2 、F b3 、F b4 、F b5 、F b6} as a sign of the existence of six branches; F bh =1 means branch

[0091] h exists, F bh =0 means branch h does not exist, 1≤h≤6;

[0092] S2. Construct the response calculation formula of a single conductor node. The response includes the current {I ch |1≤h≤6} and the voltage V at the conductor node c ;

[0093] I ch represents the current on branch h of the conductor node, that is, the current transmitted by the conductor node in the direction of h; in specific implementation, combined with Figure 1(b), let branch 1 correspond to the positive x direction, branch 2 correspond to the negative x direction, branch 3 correspond to the positive y direction, branch 4 correspond to the negative y direction, branch 5 correspond to the positive z direction, and branch 6 correspond to the negative z direction; let (m,g)∈{(1,2);(3,4);(5,6)};

[0094] I cm =Y c∑sm V c∑sm -Y c∑sm V c ;-I cg =Y c∑sg V c∑sg -Y c∑sg V c ;

[0095] Right now:

[0096] I c1 =Y c∑s1 V c∑s1 -Y c∑s1 V c ;-I c2 =Y c∑s2 V c∑s2 -Y c∑s2 V c ;

[0097] Ic3 =Y c∑s3 V c∑s3 -Y c∑s3 V c ;-I c4 =Y c∑s4 V c∑s4 -Y c∑s4 V c ;

[0098] I c5 =Y c∑s5 V c∑s5 -Y c∑s5 V c ;-I c6 =Y c∑s6 V c∑s6 -Y c∑s6 V c ;

[0099] V c = N h / D h ; N h =F bh (Y c∑sh V c∑sh -I c∑oh );

[0100] D h =F bh [Y c∑oh +Y c∑sh ((k+1)I k,k -[1] k,k )];

[0101] Among them, I cm represents the current in branch m, Y c∑sm It represents the integrated short-circuit compensation admittance corresponding to branch m, V c∑sm I represents the integrated short-circuit compensation voltage corresponding to branch m; cg represents the current in branch g, Y c∑sg It represents the integrated short-circuit compensation admittance corresponding to branch g, V c∑sg Indicates the integrated short-circuit compensation voltage corresponding to branch g; branches m and g have the same direction, and branch

[0102] m is the positive direction of Q, g is the negative direction of Q, Q∈{x,y,z}; (m,g)∈{(1,2);(3,4);(5,6)}; I ch Represents the current of branch h, 1≤h≤6;

[0103] V cN represents the total voltage matrix of the conductor cluster node, that is, the voltage vector composed of the voltages of each branch in the conductor cluster node; h and D h Both represent the integration amount corresponding to branch h in the case of multiple cores; Y c∑sh It represents the integrated short-circuit compensation admittance corresponding to branch h,

[0104] V c∑sh It represents the integrated short-circuit compensation voltage corresponding to branch h, I c∑oh Indicates the integrated amount of open circuit compensation current corresponding to branch h, Y c∑oh represents the integrated open-circuit compensation admittance corresponding to branch h; [1] k,k represent k × k dimensional matrix whose elements are all 1; k,k Represents the k-order identity matrix, which is a square matrix with all diagonal elements set to 1 and all other elements set to 0.

[0105] m∈{h,1≤h≤6}, g∈{h,1≤h≤6};

[0106] Y c∑sh =(Z coh +Z csh,const +R csh +Z th,const ) -1 ;

[0107] Y c∑oh =Y coh,const +G coh +Y th,const ;

[0108] V c∑sh =2V i c0h -2V i csh [1] k,1 -V n csh,freq [1] k,1 -V n th,freq [1] k,1 + V th +[V z / 2]F m ;

[0109] I c∑oh =-2Y coh,const (V i coh [1] k,1 )+I n coh,freq [1] k,1+I n th,freq [1] k,1 -I th [1] k,1 ;

[0110] Z csh I ch =Z csh,const I ch +V n csh,freq [1] k,1 ;

[0111] Z th I ch =Z th,const I ch +V n th,freq [1] k,1 ;

[0112] Y coh [(V coh -2V i coh )[1] k,1 ]=Y coh,const [(V coh -2V i coh )[1] k,1 ]+I n coh,freq [1] k,1 ;

[0113] Y th (V coh [1] k,1 )= Y th,const (V coh [1] k,1 )+I n th,freq [1] k,1 ;

[0114] Z coh represents the open circuit compensation impedance of branch h, Z csh Represents the short-circuit compensation impedance of branch h, Z csh,const Represents the constant term in the short-circuit compensation impedance expression of branch h, R csh Represents the short-circuit compensation resistance of branch h, Z th is the impedance of the load connected in series and parallel to the terminal of branch h, Z th,constrepresents the constant term in the branch h load impedance expression; Y coh is the open circuit compensation admittance on branch h, Y coh,const Y coh The constant term in G coh Y represents the equivalent conductance of the parallel electric field loss of branch h; th is the load admittance on branch h, Y th,const is the constant term in the load admittance expression on branch h;

[0115] V i c0h represents the incident voltage pulse matrix of branch h, V i csh represents the incident voltage pulse matrix for short-circuit compensation of branch h, [1] k,1 represents a k×1-dimensional matrix with all elements being 1; V n csh,freq Represents the voltage generated by the frequency-dependent term of the short-circuit compensation impedance on the upper branch h at time n, V n th,freq represents the voltage generated by the frequency-dependent term of the load impedance on the upper branch h at time n, V th is the series excitation voltage source of branch h, V z represents the equivalent source of the instantaneous incident electric field at the node of the conductor external medium in the z direction, F m Indicates the shielding mark. When the thin conductor has a shielding layer, that is, it is not affected by transient electromagnetic pulses, then F m =0; otherwise F m =1;

[0116] V i coh represents the open circuit compensation voltage on branch h caused by the incident pulse, I n coh,freq represents the current related to the frequency-dependent term of the open-circuit compensation admittance on the upper branch h at time n, I n th,freq represents the current generated by the frequency-dependent term of the load impedance on branch h, I th Represents the load current of the terminal series-parallel connection of branch h; I ch Represents the current on the branch h of the conductor node; V coh represents the instantaneous port voltage of branch h; represents convolution.

[0117] S3, construct the response propagation equation of the conductor node;

[0118] Let branch m and branch g have the same direction, and branch m is in the positive direction of Q, g is in the negative direction of Q, Q∈{x,y,z}, then the propagation equation in the Q direction is:

[0119] t+1 V i c0g (q-1)= t V r c0m (q)F bm ; t+1 V i c0m (q+1)= t V r c0g (q)F bg ;

[0120] t+1 V i csm (q)= t V r csm (q)(-F bm ); t+1 V i csg (q)= t V r csg (q)(-F bg );

[0121] t+1 V i com (q)= t V r com (q)F bm ; t+1 V i cog (q)= t V r cog (q)F bg ;

[0122] Among them, t represents the time, t+1 is the next time after t; q represents the qth conductor node in the Q direction, q+1 represents the next conductor node of q along the positive direction of Q, and q-1 represents the next conductor node of q along the negative direction of Q; that is, q-1, q and

[0123] q+1 is a continuous conductor node distributed along the positive direction of Q;

[0124] t+1 V i c0g (q-1) represents the incident voltage pulse matrix of the conductor node q-1 on the branch g at time t+1, t+1 V i c0m (q+1) represents the incident voltage pulse matrix of the conductor node q+1 on the branch m at time t+1;

[0125] V r c0m represents the reflected voltage pulse matrix of branch m, t V r c0m (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch m at time t r c0m ; t V r c0g (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch g at time t r c0g ;

[0126] t+1 V i csm (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch m at time t+1 i csm , t+1 V i csg (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch g at time t+1 i csm ;

[0127] t V r csm (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch m at time t r csm , t V r csg (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch g at time t r csg ;

[0128] t+1 V i com (q) represents the open circuit compensation voltage V generated by the incident pulse at the conductor node q at time t+1 on branch m i com , t+1 V i cog (q) represents the open circuit compensation voltage V generated by the incident pulse on the branch g at the conductor node q at time t+1 i cog ;

[0129] V r comrepresents the open circuit compensation reflected voltage matrix of branch m, t V r com (q) represents the open circuit compensation reflected voltage matrix V of the branch m at the conductor node q at time t r com , V r cog represents the open circuit compensation reflected voltage matrix of branch g, t V r cog (q) represents the open circuit compensation reflected voltage matrix V of the branch g at the conductor node q at time t r cog ;

[0130] S4. Determine the topological structure of the conductor nodes on the conductive structure, determine the excitation input point and the response observation point, and obtain the propagation path from the excitation input point to the response observation point; construct a conductor cluster model for each conductor node on the transmission path; determine the current V r c0m 、V r c0g 、V r csm 、V r csg 、V r com 、V r cog ;

[0131] S5. Between two adjacent conductor nodes on the propagation path, according to the V r c0m 、V r c0g 、V r csm 、V r csg 、V r com 、V r cog Combined with the propagation equation, calculate V at the rear node i c0g 、V i c0m 、V i csm 、V i csg 、V i com 、V i cog ; along the propagation path until the V of the response observation point is obtained i c0g 、V ic0m 、V i csm 、V i csg 、V i com 、V i cog , and then substitute it into the formula of step S2 to calculate the current {I cm |1≤m≤6} and its voltage V c .

[0132] The known quantities of the propagation equation are recorded as reference parameters, including: V r c0m 、V r c0g 、V r csm 、V r csg 、V r com 、V r cog ; The unknown quantities of the propagation equation are recorded as solution parameters, including: V i c0g 、V i c0m 、V i csm 、V i csg 、V i com 、V i cog ; Let {V r c0m 、V r c0g 、V r csm 、V r csg 、V r com 、V r cog}Constitute the passing array;

[0133] S5 specifically includes the following sub-steps:

[0134] S51, on the propagation path, substitute the known reference parameters of the conductor node q at time t into the propagation equation to calculate the solution parameters of the next conductor node q' at time t+1; the initial value of q is the excitation input point, and the initial value of t is the excitation pulse input time;

[0135] q'∈{q+1,q-1}.

[0136] In this step, firstly, two adjacent conductor nodes q and q' on the propagation path are obtained, the relative position relationship between q and q' on the propagation path is substituted into the propagation equation, and the solution parameters of the conductor node q' at time t+1 are calculated; the reference parameters of the conductor node q are known.

[0137] S52, determining whether the conductor node q' is a response observation point;

[0138] If yes, substitute the solution parameter of q' into the formula of step S2 to calculate the current {I cm |1≤m≤6} and its voltage V c ;

[0139] If no, then execute step S53;

[0140] S53, calculate the V of the conductor node q' r c0m 、V r c0g 、V r csm 、V r csg 、V r com 、V r cog , construct reference parameters of conductor node q';

[0141] V r c0m =(V i c0m -Z c0m I cm )F bm ; V r c0g =(V i c0g +Z c0g I cg )F bg ;

[0142] V r csm =(V i csm +Z csm I cm )F bm ; V r csg =(V i csg +Z csg I cg )F bg ;

[0143] V rcom =(V com -V i com )F bm ; V r cog =(V cog -V i cog )F bg ;

[0144] Among them, Z c0m represents the characteristic impedance of branch m, Z csm Represents the short-circuit compensation characteristic impedance of branch m; I cm Indicates branch

[0145] m current, V com represents the instantaneous terminal voltage of branch m; Z c0g represents the characteristic impedance of branch g, Z csg It represents the short-circuit compensation characteristic impedance of branch g; I cg represents the current in branch g, V cog It represents the instantaneous port voltage of branch g;

[0146] ;

[0147] V coh Represents the instantaneous terminal voltage of branch h, V com =[V coh ,h=m],V cog =[V coh ,h=g]; 1≤k≤K0, 1≤p≤K0, and p≠k, K0 is the number of parallel conductors at the conductor node; then V c kk is the sum of the voltages on conductor k on each branch in the conductor cluster node, V c pk and V c kp is the differential voltage between conductor p and conductor k in the conductor cluster node. That is, V c 11 is the sum of the voltages on conductor 1 on each branch in the conductor cluster node, V c 22 is the sum of the voltages on conductor 2 on each branch in the conductor cluster node, V c 21 is the differential voltage between conductor 2 and conductor 1 in the conductor cluster node, V c k1 is the differential voltage between conductor k and conductor 1 in the conductor cluster node, V c k2 is the differential mode voltage between conductor k and conductor 2 in the conductor cluster node; Vc 12 Conductor 1 in the conductor cluster node

[0148] and the differential mode voltage between conductor 2, V c 1k is the differential voltage between conductor 1 and conductor k in the conductor cluster node, V c 2k is the differential mode voltage between conductor 2 and conductor k in the conductor cluster node;

[0149] V c pk =∑ 6 h=1 (V c,h pp -V c,h kk )

[0150] V c,h pp is the voltage of conductor p on branch h in the conductor cluster node, V c,h kk is the voltage of conductor k on branch h in the conductor cluster node;

[0151] S54, update q to q', update t to t+1; then return to step S51.

[0152] For the conductive structure constructed by parallel conductors, the parameters are defined as follows:

[0153] ;

[0154] in, V th is the series excitation voltage source of branch h, V th 11 is the series excitation voltage source of conductor 1 on branch h, V th 22 is the series excitation voltage source of conductor 2 on branch h, V th kk is the series excitation voltage source of conductor k on branch h; Z th is the impedance of the load connected in series and parallel to the terminal of branch h, Z th 11 represents the impedance of the terminal load of conductor 1 on branch h, Z th 22 represents the impedance of the terminal load of conductor 2 on branch h, Z th kkrepresents the impedance of the terminal load of conductor k on branch h; 1≤k≤K0, K0 is the number of parallel conductors in the conductor node;

[0155] ;

[0156] I th Represents the load current of the terminal series-parallel connection of branch h; Y th is the load admittance on branch h; let 1≤p≤K0, and p≠k; then I th kk is the parallel terminal current source of conductor k on branch h, I th pk Y is the parallel terminal current source generated by the conductor k under the influence of the conductor p on the branch h; th pk Y is the terminal admittance generated by conductor k under the influence of conductor p on branch h, th kk is the terminal admittance of conductor k on branch h;

[0157] For the same conductive structure of parallel conductors, I th pk =I th kp , Y th pk =Y th kp ; that is, I th pk and I th kp Both represent the parallel terminal current source between conductors p and k on branch h, Y th pk and Y th kp Both represent the terminal admittance between conductors p and k on branch h;

[0158] ;

[0159] in, Z c0h is the characteristic impedance of branch h, Z c0h kk represents the characteristic impedance of conductor k on branch h; Z csh represents the short-circuit compensation impedance of branch h, Z csh kk represents the short-circuit compensation characteristic impedance of conductor k on branch h, Z csh pk It represents the short-circuit compensation characteristic impedance of the conductor k under the influence of the conductor p on the branch h;

[0160] ;

[0161] Among them, Y coh is the open circuit compensation admittance on branch h, Y coh kk represents the open circuit compensation admittance of conductor k on branch h, Y coh pk represents the open circuit compensation admittance generated by conductor k on branch h under the influence of conductor p; for the same conductive structure of parallel conductors, there is Y coh pk = Y coh kp ,Right now, Y coh pk and Y coh kp Both represent the open circuit compensation admittance between conductors p and k on branch h;

[0162] R csh Represents the short-circuit compensation resistance of branch h, R csh kk represents the equivalent resistance of the series magnetic field loss of conductor k on branch h, R csh pk It represents the equivalent resistance of the series magnetic field loss caused by the conductor k under the influence of the conductor p on the branch h;

[0163] ;

[0164] G coh represents the equivalent conductance of the parallel electric field loss of branch h; G coh kk represents the open-circuit additional conductance of conductor k on branch h; G coh pk represents the additional open-circuit conductance of the conductor k on the branch h due to the influence of the conductor p on the branch h. For the same conductive structure of parallel conductors, there is G coh pk = G coh kp ,Right now, G coh pk and G cohkp Both represent the open-circuit additional conductance between conductors p and k on branch h;

[0165] ;

[0166] Among them, V i c0h represents the incident voltage pulse matrix of branch h, represents the incident pulse on conductor k on branch h; V i csh represents the short-circuit compensation caused by the incident pulse on branch h, represents the short circuit compensation between conductors p and k on branch h caused by the incident pulse, represents the short circuit compensation caused by the incident pulse on the conductor k of branch h; V i coh represents the open circuit compensation caused by the incident pulse on branch h, represents the open circuit compensation between conductors p and k on branch h caused by the incident pulse, represents the open circuit compensation caused by the incident pulse on the conductor k of the branch h;

[0167] In this embodiment, it is necessary to solve the specified current and voltage parameters in combination with the characteristic parameters of the conductor used in the conductive structure and the equivalent circuit; the characteristic parameters include: impedance parameters, resistance parameters, admittance parameters and conductance parameters;

[0168] Impedance parameters include: characteristic impedance on branch h Z c0h , the impedance Z of the load connected in series and parallel to the terminal of branch h th , short-circuit compensation impedance Z of branch h csh ;

[0169] The resistance parameters include: short-circuit compensation resistance R of branch h csh ;

[0170] The admittance parameters include: open circuit compensation admittance Y on branch h coh , load admittance Y on branch h th ;

[0171] Conductivity parameters include: parallel electric field loss equivalent conductance G of branch h coh ;

[0172] The specified current and voltage parameters include: the sum of the voltages of conductor k on each branch in the conductor cluster node V c kk , conductors in conductor cluster nodes

[0173] The differential mode voltage V between conductor p and conductor k c pk wait;

[0174] In addition, the load current I connected in series and parallel to the terminal of branch h th , the series excitation voltage source of branch h V th And the instantaneous incident electric field equivalent source V at the conductor external dielectric node in the z direction z is the loading parameter of the equivalent circuit.

[0175] In this embodiment, for a double-core cable consisting of two identical cores, a Figure 3 The equivalent circuit model shown in Figure 1. When the cable is a double-core cable, that is, it contains two conductors, an equivalent circuit is established for each thin conductor, that is, each equivalent circuit contains branches in two directions of the conductor cluster node that are collinear; assuming that branch h is collinear with branch g, the equivalent circuits of the thin conductors corresponding to branch h and branch g are as follows: Figure 3 shown.

[0176] In the conductor cluster model, the transmission time of the pulse in a certain direction of the grid is fixed as , the transmission time of each branch is . Δ l represents the length of the thin conductor in the grid, that is, the length of the grid edge, Δ l is the set value; Δ l / 2 represents the conductor segment length, that is, the length of each branch in the simplified diagram of the conductor cluster node.

[0177] Definition: Subscript c represents cable; subscript s represents short-circuit compensation, subscript t represents load-related items, subscript o represents open-circuit compensation, subscript const represents constant, subscript freq represents frequency-related, subscript h represents branch, Z represents impedance, L represents inductance, Y represents admittance, C represents capacitance, G represents conductance, and V represents voltage; superscript i represents the incident wave, the superscript r Represents the reflected pulse.

[0178] Figure 3 middle, I ch 11 represents the current in conductor 1 on branch h, Z c0h 11 represents the characteristic impedance of conductor 1 on branch h;

[0179] R csh 11 represents the equivalent resistance of the series magnetic field loss of conductor 1 on branch h; Z th 11 represents the impedance of the terminal load of conductor 1 on branch h, Zcsh 11 represents the short-circuit compensation characteristic impedance of conductor 1 on branch h, V csh 12 It represents the coupled short-circuit additional voltage generated by the upper conductor 1 of branch h affecting the lower conductor 2; V z represents the equivalent source of the instantaneous incident electric field at the external dielectric node of the conductor in the z direction, V th 11 is the series excitation voltage source of conductor 1 on branch h;

[0180] I ch 22 represents the current in conductor 2 on branch h, Z c0h 22 represents the characteristic impedance of conductor 2 on branch h; R csh 22 represents the equivalent resistance of the series magnetic field loss of conductor 2 on branch h; Z th 22 represents the impedance of the terminal load of conductor 2 on branch h, Z csh 22 represents the short-circuit compensation characteristic impedance of conductor 2 on branch h, V csh 21 It represents the coupled short-circuit additional voltage generated by the upper conductor 2 of branch h affecting the lower conductor 1; V th 22 is the series excitation voltage source of conductor 2 on branch h; Y coh 11 represents the open circuit compensation admittance of conductor 1 on branch h, G coh 11 represents the open-circuit additional conductance of conductor 1 on branch h; Y coh 12 It represents the open circuit compensation admittance caused by the upper conductor 1 affecting the lower conductor 2 of branch h. G coh 12 I represents the open circuit additional conductance caused by the upper conductor 1 of branch h affecting the lower conductor 2; th 12 is the parallel terminal current source generated by the influence of the conductor 1 on the branch h on the conductor 2, I th 11 is the parallel terminal current source of conductor 1 on branch h, Y th 12 Y is the terminal admittance generated by the conductor 1 on branch h affecting the conductor 2 below,th 11 is the terminal admittance of conductor 1 on branch h;

[0181] Y coh 22 represents the open circuit compensation admittance of conductor 2 on branch h, G coh 22 I represents the open circuit additional conductance of conductor 2 on branch h; th 22 is the parallel terminal current source of conductor 2 on branch h, Y th 22 is the terminal admittance of conductor 2 on branch h;

[0182] V c 12 is the differential voltage between conductor 1 and conductor 2 in the conductor cluster node, V c 22 is the sum of the voltages on conductor 2 on each branch in the conductor cluster node;

[0183] R csh 12 It represents the equivalent resistance of the series magnetic field loss caused by the upper conductor 1 affecting the lower conductor 2 in branch h; Z csh 12 It represents the short-circuit compensation characteristic impedance caused by the upper conductor 1 affecting the lower conductor 2 of branch h; R csh 21 It represents the equivalent resistance of the series magnetic field loss caused by the upper conductor 2 of branch h affecting the lower conductor 1; Z csh 21 It represents the short-circuit compensation characteristic impedance caused by the upper conductor 2 of branch h affecting the lower conductor 1.

[0184] In combination with specific embodiments, Figure 4 The metal grid shown is taken as a research object to verify the above-mentioned TLM-based multi-branch conductor cluster transient response method for conductive structures.

[0185] 5(a), in this embodiment, taking the four crossed conductors at the bottom left side of the metal grid as an example, the hexahedral grid division result is shown in FIG5(b); each conductor in the hexahedral grid forms a conductor node, and the conductor cluster model corresponding to a single conductor node is shown in FIG1(a) and FIG1(b).

[0186] In this embodiment, a lightning surge generator is used as the experimental excitation to apply a voltage excitation of 1.2 / 50 μs waveform to the metal grid. At the same time, a current coil with a transformation ratio of 1:1 is used to collect current signals; a high-voltage probe with an attenuation ratio of 1000:1 is used to collect voltage signals. The metal grid is 0.4m long, 0.2m wide, and 1.0m high.

[0187] Experimental wiring as Figure 6 As shown in Figure 1. A 100Ω non-inductive resistor is connected in series in the loop for protection. A high-voltage probe is connected to the top and bottom of the metal grid to measure the potential difference signal.

[0188] The radius of the metal conductor that constitutes the metal grid is 0.001m. The capacitance per unit length C of the conductor in this model can be approximated by the calculation formula of the square coaxial cable. w , inductance per unit length L w And the resistance per unit length R w :

[0189] ;

[0190] a is the conductor radius, a=0.001m; b is the side length of the hexahedral mesh, in this embodiment b=20a, μ w is the magnetic permeability of the conductor, σ w is the conductivity of the conductor, μ w =1, σ w =1.4×10 6 S / m, is the dielectric constant of the medium, and the value here is =1.

[0191] In this embodiment, after the lightning surge generator is started, the waveform signal collected by the high-voltage probe is displayed through a multi-channel oscilloscope and saved as an experimental measurement result; at the same time, the lightning surge generator is used as an excitation source, the node connected to the high-voltage probe at the top of the metal grid is used as an excitation point, and the node connected to the high-voltage probe at the bottom of the metal grid is used as a response observation point. The above-mentioned TLM-based multi-branch conductor cluster transient response method for conductive structures is executed to calculate the voltage response of the response observation point. In this embodiment, the calculation results are compared with the experimental measurement results. Figure 7 As shown in Figure 2, it can be seen that the calculated results are consistent with the experimental results, proving the effectiveness of the conductor cluster node calculation.

[0192] Of course, it is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also includes the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-limiting, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any reference numerals in the claims should not be regarded as limiting the claims involved.

[0193] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

[0194] The techniques, shapes, and structural parts not described in detail in the present invention are all well-known techniques.

Claims

1. A TLM-based multi-branch conductor cluster transient response method for a conductive structure, characterized in that: The following steps are involved: S1. Divide the research object into conductor nodes through hexahedral meshes, and arrange thin conductors in the hexahedral meshes to construct a conductor cluster model corresponding to the conductor nodes; The conductor cluster model is composed of thin conductors arranged in three directions (x, y, z) of the Cartesian coordinate system, and the thin conductors cross at the center of the hexahedral grid to form six branches extending outward from the intersection of the thin conductors; the hexahedral grid adopts a cubic structure, and the side length of the hexahedral grid is greater than the cross-sectional diameter of the conductor node; the research object is a conductive structure; S2. Construct the response calculation formula of a single conductor node. The response includes the current {I ch |1≤h≤6} and the voltage V at the conductor node c ; S3, construct the response propagation equation of the conductor node; S4, determining the topological structure of the conductor nodes on the conductive structure, determining the excitation input point and the response observation point, and obtaining the propagation path from the excitation input point to the response observation point; S5. Starting from the excitation point on the propagation path, the responses of adjacent conductor nodes are calculated in sequence until the response of the response observation point is obtained.

2. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 1, characterized in that: Assume that branch m and branch g have the same direction, and branch m is in the positive direction of Q, and branch g is in the negative direction of Q, Q∈{x,y,z}, then the propagation equation in the Q direction in S3 is: t+1 V i c0g (q-1)= t V r c0m (q)F bm ; t+1 V i c0m (q+1)= t V r c0g (q)F bg ; t+1 V i csm (q)= t V r csm (q)(-F bm ); t+1 V i csg (q)= t V r csg (q)(-F bg ); t+1 V i com (q)= t V r com (q)F bm ; t+1 V i cog (q)= t V r cog (q)F bg ; Where t represents the moment, t+1 represents the next moment of t; superscript i represents the incident voltage, superscript r represents the reflected voltage; q-1, q and q+1 are continuous conductor nodes distributed along the positive direction of Q; t+1 V i c0g (q-1) represents the incident voltage pulse matrix V of the conductor node q-1 on the branch g at time t+1 i c0g , t+1 V i c0m (q+1) represents the incident voltage pulse matrix V of conductor node q+1 on branch m at time t+1 i c0m ; V r c0m represents the reflected voltage pulse matrix of branch m, t V r c0m (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch m at time t r c0m ; t V r c0g (q) represents the reflected voltage pulse matrix V of the conductor node q on the branch g at time t r c0g ; t+1 V i csm (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch m at time t+1 i csm , t+ 1V i csg (q) represents the short-circuit compensation incident voltage pulse matrix V of the conductor node q on the branch g at time t+1 i csm ; t V r csm (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch m at time t r csm , t V r csg (q) represents the short-circuit compensation reflected voltage pulse matrix V of the conductor node q on the branch g at time t r csg ; t+1 V i com (q) represents the open circuit compensation voltage V generated by the incident pulse at the conductor node q at time t+1 on branch m i com , t+ 1V i cog (q) represents the open circuit compensation voltage V generated by the incident pulse on the branch g at the conductor node q at time t+1 i cog ; t V r com (q) represents the open circuit compensation reflected voltage matrix V of the conductor node q at time t on branch m r com , t V r cog (q) represents the open circuit compensation reflected voltage matrix V of the branch g at the conductor node q at time t r cog ; F bm is the sign of branch m; F bm When the value is "1", it means that branch m exists. bm The value is "0" if branch m does not exist; bg is the sign of branch g; F bg When the value is "1", it means that branch g exists, F bg A value of "0" indicates that branch g does not exist.

3. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 2, characterized in that: In S2, the response calculation formula is: I cm =Y c∑sm V c∑sm -Y c∑sm V c ;-I cg =Y c∑sg V c∑sg -Y c∑sg V c ; V c = N h / D h ;N h =F bh (Y c∑sh V c∑sh -I c∑oh ); D h =F bh [Y c∑oh +Y c∑sh ((k+1)I k,k -[1] k,k )];Y c∑sh =(Z coh +Z csh,const +R csh +Z th,const ) -1 ; AND c∑oh =And coh,const +G coh +Y th,const ; V c∑sh =2V i c0h -2V i csh [1] k,1 -V n csh,freq [1] k,1 -V n th,freq [1] k,1 + V th +[V z / 2]F m ; I c∑oh =-2Y coh,const (V i coh [1] k,1 )+I n coh,freq [1] k,1 +I n th,freq [1] k,1 -I th [1] k,1 ; Among them, I cm represents the current in branch m, Y c∑sm It represents the integrated short-circuit compensation admittance corresponding to branch m, V c∑sm I represents the integrated short-circuit compensation voltage corresponding to branch m; cg represents the current in branch g, Y c∑sg It represents the integrated short-circuit compensation admittance corresponding to branch g, V c∑sg It represents the integrated amount of short-circuit compensation voltage corresponding to branch g; V c represents the total voltage matrix of the conductor cluster nodes; N h and D h Both represent the integration amount corresponding to branch h in the case of multiple cores; Y c∑sh It represents the integrated short-circuit compensation admittance corresponding to branch h, V c∑sh It represents the integrated short-circuit compensation voltage corresponding to branch h, I c∑oh Indicates the integrated amount of open circuit compensation current corresponding to branch h, Y c∑oh represents the integrated open-circuit compensation admittance corresponding to branch h; [1] k,k represent k × k A matrix with dimensions whose elements are all 1; [1] k,1 represent k × 1 dimensional matrix whose elements are all 1; k,k represents the k-order identity matrix; Z coh represents the open circuit compensation impedance of branch h, Z csh Represents the short-circuit compensation impedance of branch h, Z csh,const Represents Z csh The constant term in the expression, R csh Represents the short-circuit compensation resistance of branch h, Z th is the load impedance of the terminal series-parallel connection of branch h, Z th,const Represents Z th The constant term in the expression; Y coh is the open circuit compensation admittance on branch h, Y coh,const Y coh The constant term in G coh Y represents the equivalent conductance of the parallel electric field loss of branch h; th is the load admittance on branch h, Y th,const Y th Constant terms in expressions; V i c0h represents the incident voltage pulse matrix of branch h, V i csh represents the incident voltage pulse matrix for short-circuit compensation of branch h, [1] k,1 represents a k×1 1 matrix, V n csh,freq Represents the voltage generated by the frequency-dependent term of the short-circuit compensation impedance on the upper branch h at time n, V n th,freq represents the voltage generated by the frequency-dependent term of the load impedance on the upper branch h at time n, V th is the series excitation voltage source of branch h, V z represents the equivalent source of the instantaneous incident electric field at the node of the conductor external medium in the z direction, F m Indicates shielding sign. When the thin conductor is not affected by transient electromagnetic pulses, F m =0; otherwise F m =1; V i coh represents the open circuit compensation voltage on branch h caused by the incident pulse, I n coh,freq represents the current related to the frequency-dependent term of the open-circuit compensation admittance on the upper branch h at time n, I n th,freq represents the current generated by the frequency-dependent term of the load impedance on branch h, I th Represents the load current in series and parallel at the terminals of branch h.

4. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 3, characterized in that: V n csh,freq 、V n th,freq ,I n coh,freq ,I n th,freq The calculation formula is as follows: Z csh I ch =Z csh,const I ch +V n csh,freq [1] k,1 ; Z th I ch =Z th,const I ch +V n th,freq [1] k,1 ; Y coh [(V coh -2V i coh )[1] k,1 ]=Y coh,const [(V coh -2V i coh )[1] k,1 ]+I n coh,freq [1] k,1 ; Y th (V coh [1] k,1 )= Y th,const (V coh [1] k,1 )+I n th,freq [1] k,1 ; in, represents convolution; Z csh Represents the short-circuit compensation impedance of branch h, Z csh,const Represents Z csh Constant term in an expression; I ch represents the current on the branch h of the conductor node; Z th is the load impedance of the terminal series-parallel connection of branch h, Z th,const Represents Z th Constant terms in expressions; Y coh is the open circuit compensation admittance on branch h, Y coh,const Y coh The constant term in V coh Represents the instantaneous port voltage of branch h; V i coh represents the open circuit compensation voltage on branch h generated by the incident pulse; Y th is the load admittance on branch h, Y th,const Y th A constant term in an expression.

5. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 3, characterized in that: Step S5 The following steps are included: S51, obtaining the reference parameters of the conductor node q, and substituting the known reference parameters of the conductor node q at time t into the propagation equation to calculate the solution parameters of the next conductor node q' at time t+1 on the propagation path; the initial value of q is the excitation input point, and the initial value of t is the excitation pulse input time; Reference parameters include: the reflected voltage pulse matrix V of branch h r c0h , short-circuit compensation reflected voltage pulse matrix of branch h V r csh , open circuit compensation reflected voltage matrix V of branch h r coh ; The solution parameters include: the incident voltage pulse matrix V of branch h i c0h , the short-circuit compensation incident voltage pulse matrix V of branch h i csh , branch h is the open circuit compensation voltage V generated by the incident pulse i coh ; S52, determine whether the conductor node q' is a response observation point; if yes, calculate the current {I cm |1≤m≤6} and its voltage V c ; No, execute step S53; S53, calculating reference parameters of conductor node q'; V r c0m =(V i c0m -Z c0m I cm )F bm ;V r c0g =(V i c0g +Z c0g I cg )F bg ; V r csm =(V i csm +Z csm I cm )F bm ;V r csg =(V i csg +Z csg I cg )F bg ; V r com =(V com -V i com )F bm ;V r cog =(V cog -V i cog )F bg ; Among them, V i c0m represents the incident voltage pulse matrix of branch m, Z c0m represents the characteristic impedance of branch m, I cm represents the current in branch m, F bm Indicates the sign of branch m; V i c0g represents the incident voltage pulse matrix of branch g, Z c0g Indicates the branch g Characteristic impedance, I cg represents the current in branch g, F bg Indicates the sign of branch g; V i csm represents the short-circuit compensation incident voltage pulse matrix of branch m, Z csm Represents the short-circuit compensation characteristic impedance of branch m; V com It represents the instantaneous port voltage of branch m; V i com V represents the open circuit compensation voltage generated by the incident pulse in branch m; i csg represents the short-circuit compensation incident voltage pulse matrix of branch g, Z csg Represents the short-circuit compensation characteristic impedance of branch g; V cog Represents the instantaneous port voltage of branch g; V i cog It represents the open circuit compensation voltage generated by the incident pulse in branch g; branch m is collinear with branch g, and branch m is in the forward direction and branch g is in the reverse direction; S54, update q to q', update t to t+1; then return to step S51.

6. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 5, characterized in that: Let the instantaneous terminal voltage of branch h be V coh ; ； V c pk =∑ 6 h=1 (V c,h pp -V c,h kk ); Among them, V c,h pp is the voltage of conductor p on branch h in the conductor cluster node, V c,h kk is the voltage of conductor k on branch h in the conductor cluster node; V c pk and V c kp Both represent the differential mode voltage between conductor p and conductor k in the conductor cluster node, 1≤k≤K0, 1≤p≤K0, and p≠k, K0 is the number of parallel conductors in the conductor node.

7. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 6, characterized in that: The load current of the terminal series-parallel connection of branch h is denoted as I th , the load admittance on branch h is denoted as Y th , the open circuit compensation admittance on branch h is recorded as Y coh , the equivalent conductance of the parallel electric field loss of branch h is denoted as G coh ,have: ； ； Among them, I th kk is the parallel terminal current source of conductor k on branch h, I th pk Y is the parallel terminal current source generated by the conductor k under the influence of the conductor p on the branch h; th kk is the terminal admittance of conductor k on branch h, Y th pk is the terminal admittance generated by conductor k under the influence of conductor p on branch h; Y coh kk represents the open circuit compensation admittance of conductor k on branch h, Y coh pk Represents the conductor on branch h The open circuit compensation admittance generated by conductor k under the influence of p; G coh kk represents the open-circuit additional conductance of conductor k on branch h; G coh pk It represents the additional open-circuit conductance of the conductor k under the influence of the conductor p on the branch h.

8. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 7, characterized in that: The equivalent circuit of a multi-core cable composed of the same cores includes: I th pk =I th kp ,Y th pk =Y th kp ; Y coh pk = Y coh kp , G coh pk = G coh kp ; Among them, I th kp Y is the parallel terminal current source generated by the conductor p under the influence of the conductor k on the branch h; th kp is the terminal admittance generated by conductor p under the influence of conductor k on branch h; Y coh kp Represents the open circuit compensation of conductor p on branch h under the influence of conductor k Type admittance; G coh kp It represents the additional open-circuit conductance of the conductor p caused by the influence of the conductor k on the branch h.

9. The TLM-based multi-branch conductor cluster transient response method for a conductive structure according to claim 1, characterized in that: The hexahedral grid adopts a cubic structure, and the side length of the hexahedral grid is greater than or equal to 10 times the cross-sectional diameter at the conductor node.

10. A TLM-based multi-branch conductor cluster transient response system for a conductive structure, characterized in that: It comprises a memory and a processor, wherein a computer program is stored in the memory, the processor is connected to the memory, and the processor is used to execute the computer program to implement the TLM-based multi-branch conductor cluster transient response method for a conductive structure as described in any one of claims 1-8.

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