CN115828819B - High-frequency coupling current calculation method and system for high-precision transmission line - Google Patents
High-frequency coupling current calculation method and system for high-precision transmission line Download PDFInfo
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Abstract
The invention discloses a high-frequency coupling current calculation method and a high-frequency coupling current calculation system for a high-precision transmission line, which find the transmission characteristic of the transmission line under the high-frequency condition, and correct a propagation constant by adopting a complete impedance formula to replace a Su De formula which is not accurate enough. In the case that the excitation is a voltage source, the Su De formula cannot guarantee the accuracy, and the calculation accuracy of the current is greatly improved by adopting a complete impedance formula. The current of each area is solved separately, so that the calculation efficiency is very high, the analytic expression is adopted to replace the step-by-step solution, the calculation time is only two minutes, and is only one sixth of the original current under the condition of 200 m, meanwhile, the transmission line current can be solved accurately, and theoretical guidance is provided for protection research.
Description
Technical Field
The invention relates to the field of high-frequency current calculation of frequency domain multi-conductor transmission lines, in particular to a high-frequency coupling current calculation method and a high-frequency coupling current calculation system of a high-precision transmission line.
Background
When the height of the transmission line is quite equal to or larger than one tenth of the minimum wavelength of a typical high-frequency electromagnetic field in calculation, the application range of the classical transmission line approximation is exceeded, and the line response cannot be calculated by adopting a classical transmission line method. While conventional full-wave solvers (e.g., moment methods) can solve the above problems, their computational cost will increase geometrically with increasing line length, and therefore their solving efficiency is unacceptable in the case of longer transmission line systems.
The asymptotic high-frequency coupling model of the transmission line can accurately and efficiently process high-frequency current under plane wave excitation. However, when the excitation becomes a voltage source, the error in the propagation constant at this time will greatly reduce the accuracy of the model. Therefore, it is necessary to provide a technique for improving the accuracy of the high-frequency coupling model, and to correct an error in the current due to the propagation constant.
Disclosure of Invention
The invention aims to provide a high-frequency coupling current calculation method and a high-frequency coupling current calculation system for a high-precision transmission line, so as to solve the problems in the prior art.
In order to achieve the above purpose, the invention adopts the following technical scheme:
a high-frequency coupling current calculation method of a high-precision transmission line comprises the following steps:
step one: dividing the multi-conductor transmission line into a first region, a second region and a third region according to the transmission line height in the original line by utilizing an asymptotic theory and a classical transmission line model, wherein the first region is a left end region, the second region is a middle region and the third region is a right end region;
step two: correcting the propagation constant of the second current in the region by using a complete impedance formula;
step three: analyzing and expressing the current of the transmission line by using a series of unknown coefficients related to the second current, the first current and the third current; adopting an auxiliary line with the same parameters as the original line but the length of the auxiliary line is only six times of the height, simulating the auxiliary line by using full-wave software to obtain the simulation current of the auxiliary line, and solving a series of unknown coefficients related to the second current, the first current and the third current in the original line by using the simulation current of the auxiliary line;
step four: and (3) obtaining the high-frequency coupling current of the transmission line by using the propagation constant corrected by the complete impedance formula in the second step and a series of unknown coefficients obtained in the third step.
Further, in the first step, three regions of the multi-conductor transmission line are divided according to the transmission line heights: region one: 0. is less than or equal tox≤ 2hAnd (2) a second area: 2h<x<L-2hAnd region three:L-2h≤x≤L, wherein ,xas the line axial coordinate,hfor the height of the transmission line,Lis the length of the transmission line.
Further, in the second step, the propagation constant of the second current in the region is corrected by using a complete impedance formula;
the representation of the area two current is as follows:
in the formula ：I-transmission line current;
-line axial coordinates;T-a diagonal transformation matrix; />
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
the propagation constant is expressed as the product of impedance and admittance, and the impedance matrix and the admittance matrix are solved as follows, specifically:
wherein: z-an impedance matrix;j-imaginary units;ω-angular frequency;
-magnetic permeability; />
-a wiremAnd wirenIs a distance of (2);d m -a wiremIs of a height of (2);d n -a wirenIs of a height of (2);y-integrating the variables; />
—— and yA related function;
wherein ,
the expression is adopted as follows:
in the formula ：
-ground conductivity; />
-ground relative permittivity; />
-dielectric constant of air;
the admittance matrix is expressed by the following formula:
in the formula ：Y-admittance matrix;C-a capacitive matrix;L-an inductance matrix;
the inductance matrix is expressed as:
the propagation constant is represented by the product of impedance and admittance:
in the formula ,
-a propagation constant of the first transmission line; />
-a propagation constant of the second transmission line;N-a number of multi-conductor transmission lines; />
-firstNPropagation constant of the root transmission line.
In the third step, the transmission line current is expressed by analyzing a series of unknown coefficients related to the second current, the first current and the third current, specifically as follows:
the expression of the region two current is:
in the formula ：T-a diagonal transformation matrix;
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current; />
——NAn array of order units,Nthe number of transmission lines; />
-a reflection coefficient associated with region one; />
-a reflection coefficient associated with region three; />
-a voltage source coefficient associated with region one; />
-a voltage source coefficient associated with region three;
the expressions of the first current and the third current are:
in the formula ：
-region one and reflection related unknown coefficients; />
-unknown coefficients of region three and reflection correlation; />
-area one is unknown in relation to the voltage sourceCoefficients; />
-region three, an unknown coefficient related to the voltage source;
and adopting an auxiliary line with the same parameters as the original line and the length of only six times of the height, simulating the auxiliary line by using full-wave software, and carrying the obtained current solution of the auxiliary line into the expressions of the first current, the second current and the third current, so as to obtain specific values of a series of unknown coefficients related to the second current, the first current and the third current in the original line.
Further, in the fourth step, a specific numerical value of the high-frequency coupling current of the transmission line is obtained by using the propagation constant corrected by the complete impedance formula in the second step and a series of unknown coefficients obtained in the third step;
the calculation formula of the high-frequency coupling current of the transmission line is as follows:
a high-precision transmission line high-frequency coupled current computing system, comprising:
and a current solving module: the multi-conductor transmission line is divided into a first region, a second region and a third region according to the transmission line height in an original line by utilizing an asymptotic theory and a classical transmission line model, wherein the first region is a left end region, the second region is a middle region and the third region is a right end region;
propagation constant correction module: the method is used for correcting the propagation constant of the second current in the region by utilizing a complete impedance formula;
and a correlation coefficient solving module: the method is used for analyzing and expressing the transmission line current by utilizing a series of unknown coefficients related to the second current, the first current and the third current; adopting an auxiliary line with the same parameters as the original line but the length of the auxiliary line is only six times of the height, simulating the auxiliary line by using full-wave software to obtain the simulation current of the auxiliary line, and solving a series of unknown coefficients related to the second current, the first current and the third current in the original line by using the simulation current of the auxiliary line;
and the full line current solving module is used for: the method is used for correcting the propagation constant and a series of unknown coefficients obtained by using a complete impedance formula to obtain the high-frequency coupling current of the transmission line.
Further, in the current solving module, three areas of the multi-conductor transmission line are divided according to the height of the transmission line: region one: 0. is less than or equal tox≤ 2hAnd (2) a second area: 2h<x<L-2hAnd region three:L-2h≤x≤L, wherein ,xas the line axial coordinate,hfor the height of the transmission line,Lis the length of the transmission line.
Further, in the propagation constant correction module, a complete impedance formula is utilized to correct the propagation constant of the second current in the region;
the representation of the area two current is as follows:
in the formula ：I-transmission line current;
-line axial coordinates;T-a diagonal transformation matrix; />
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
the propagation constant is expressed as the product of impedance and admittance, and the impedance matrix and the admittance matrix are solved as follows, specifically:
wherein: z-an impedance matrix;j-imaginary units;ω-angular frequency;
-magnetic permeability; />
-a wiremAnd wirenIs a distance of (2);d m -a wiremIs of a height of (2);d n -a wirenIs of a height of (2);y-integrating the variables; />
—— and yA related function;
wherein ,
the expression is adopted as follows:
in the formula ：
-ground conductivity; />
-ground relative permittivity; />
-dielectric constant of air;
the admittance matrix is expressed by the following formula:
in the formula ：Y-admittance matrix;C-a capacitive matrix;L-an inductance matrix;
the inductance matrix is expressed as:
the propagation constant is represented by the product of impedance and admittance:
in the formula ,
-a propagation constant of the first transmission line; />
-a propagation constant of the second transmission line;N-a number of multi-conductor transmission lines; />
-firstNPropagation constant of the root transmission line.
Further, in the correlation coefficient solving module, the transmission line current is expressed by analyzing a series of unknown coefficients related to the second current, the first current and the third current, which is specifically as follows:
the expression of the region two current is:
in the formula ：T-a diagonal transformation matrix;
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
——Nan array of order units,Nthe number of transmission lines; />
-a reflection coefficient associated with region one; />
-a reflection coefficient associated with region three; />
-a voltage source coefficient associated with region one; />
-a voltage source coefficient associated with region three;
the expressions of the first current and the third current are:
in the formula ：
-region one and reflection related unknown coefficients; />
-unknown coefficients of region three and reflection correlation; />
-an unknown coefficient associated with the first region and the voltage source; />
-region three, an unknown coefficient related to the voltage source;
and adopting an auxiliary line with the same parameters as the original line and the length of only six times of the height, simulating the auxiliary line by using full-wave software, and carrying the obtained current solution of the auxiliary line into the expressions of the first current, the second current and the third current, so as to obtain specific values of a series of unknown coefficients related to the second current, the first current and the third current in the original line.
Further, in the all-line current solving module, a specific numerical value of the high-frequency coupling current of the transmission line is obtained by utilizing the propagation constant corrected by the complete impedance formula and a series of solved unknown coefficients;
the calculation formula of the high-frequency coupling current of the transmission line is as follows:
compared with the prior art, the invention has the following beneficial technical effects:
the invention finds the transmission characteristic of the transmission line under the high frequency condition, and calculates the propagation constant by adopting a complete impedance formula. Under the condition that excitation is a voltage source, a complete impedance formula is adopted, so that the calculation accuracy of current is greatly improved, the current along the overhead line is accurately predicted, and theoretical guidance is provided for protection research.
In addition, the invention separately solves the current of each area, has high calculation efficiency, and because the analytic expression is adopted to replace the step-by-step solution, the calculation time is only two minutes, and is only one sixth of the original current under the condition of 200 m, and meanwhile, the transmission line current can be accurately solved.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention.
FIG. 1 is a three-conductor transmission line structure in accordance with one embodiment of the present invention;
FIG. 2 is a comparison of the high frequency current response amplitude of the first wire and the current response amplitude of the full wave software calculated using a high frequency coupling model of a conventional formula in an embodiment of the present invention;
fig. 3 is a comparison of the high frequency current response amplitude of the first wire and the current response amplitude of the full wave software in an embodiment of the present invention.
Detailed Description
In order that those skilled in the art will better understand the present invention, a technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in which it is apparent that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present invention without making any inventive effort, shall fall within the scope of the present invention.
It should be noted that the terms "first," "second," and the like in the description and the claims of the present invention and the above figures are used for distinguishing between similar objects and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used may be interchanged where appropriate such that the embodiments of the invention described herein may be implemented in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Example 1
The invention provides a high-frequency coupling current calculation method of a high-precision transmission line, which utilizes a complete impedance formula to improve a high-frequency coupling model of the transmission line, so that the high-frequency coupling model can accurately solve the high-frequency current on the transmission line.
Step one: as shown in fig. 1, consider a three conductor transmission line structure of 200 m length and 10 m height, in which a voltage source with a frequency of 100MHz and an amplitude of 1V is respectively located on the second transmission lineThe left and right loads of the overhead line are both 50Ω. The relative dielectric constant, conductivity and permeability of the ground are epsilon respectively g =10、σ g =0.1S/m and u 0 . The spacing between adjacent overhead lines is 1m, and the radius of the overhead lines is 1 cm. The region of the transmission line is divided into three regions, namely region one (0.ltoreq.xLess than or equal to 20 m), zone two (20 m)<x<180 m) and region III (180 m.ltoreq.180)x≤200 m)。
Step two: and correcting the propagation constant of the second current in the region with a complete impedance formula. The general representation of the area two current is:
in the formula ：I-transmission line current;
-line axial coordinates;T-a diagonal transformation matrix; />
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
the propagation constant may be expressed as the product of impedance and admittance, and the impedance matrix and the admittance matrix are solved as follows, specifically:
wherein: z-an impedance matrix;j-imaginary units;ω-angular frequency;
-magnetic permeability; />
-a wiremAnd wirenIs a distance of (2);d m -a wiremIs of a height of (2);d n -a wirenIs of a height of (2);y-integrating the variables; />
—— and yA related function;
wherein ,
the expression is adopted as follows:
in the formula ：
-ground conductivity; />
-ground relative permittivity; />
-dielectric constant of air;
the admittance matrix is expressed by the following formula:
in the formula ：Y-admittance matrix;C-a capacitive matrix;L-an inductance matrix;
the inductance matrix is expressed as:
the propagation constant is represented by the product of impedance and admittance:
in the formula ,
-a propagation constant of the first transmission line; />
-a propagation constant of the second transmission line;N-a number of multi-conductor transmission lines; />
-firstNPropagation constant of the root transmission line.
Step three: and analyzing and expressing the transmission line current by using a series of unknown coefficients related to the second current, the first current and the third current. The expression of the second current in the region is:
in the formula ：T-a diagonal transformation matrix;
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current; />
——NAn array of order units,Nthe number of transmission lines; />
-a reflection coefficient associated with region one; />
-a reflection coefficient associated with region three; />
-a voltage source coefficient associated with region one; />
-voltage source coefficient associated with region three.
For the currents of region one and region three, there are:
in the formula ：
-region one and reflection related unknown coefficients; />
-unknown coefficients of region three and reflection correlation; />
-an unknown coefficient associated with the first region and the voltage source; />
-unknown coefficients of region three related to voltage source.
Because the specific values of a series of unknown coefficients related to the second current, the first current and the third current are irrelevant to the length, an auxiliary line with the same parameters as the three-conductor transmission line and the length of only six times of the height is adopted, the auxiliary line is simulated by using full-wave software to obtain a current solution of the auxiliary line, and the current solution of the auxiliary line is used to obtain a series of unknown coefficients related to the second current, the first current and the third current in the original line; because the length of the auxiliary line is shorter, the current of the auxiliary short line is solved by adopting a full-wave numerical method, and the calculation cost is greatly reduced;
step four: and (3) obtaining high-frequency coupling current of the transmission line by using a series of unknown coefficients and the propagation constant corrected by the complete impedance formula obtained in the step (III), wherein the high-frequency coupling current is expressed as follows:
in this embodiment, as shown in fig. 1, 2 and 3, the high-frequency current response amplitude calculated before and after the high-frequency coupling current calculation method using a high-precision transmission line is compared with the current response amplitude obtained using the full-wave method. It can be seen that before the accuracy improvement technique is used, a large error is caused by using the high-frequency coupling model, and the two curves are basically not matched; and after the precision improvement technology is used, the two curves are well matched.
The invention gives the transmission characteristic of the multi-conductor transmission line under the high frequency condition, calculates the propagation constant by adopting a complete formula, obviously improves the precision, can accurately solve and obtain the current on the line, and provides theoretical guidance for subsequent protection.
Example two
The invention also provides a high-frequency coupling current calculation system of the high-precision transmission line, which comprises the following components:
and a current solving module: the multi-conductor transmission line is divided into a first region, a second region and a third region according to the transmission line height in an original line by utilizing an asymptotic theory and a classical transmission line model, wherein the first region is a left end region, the second region is a middle region and the third region is a right end region;
propagation constant correction module: the method is used for correcting the propagation constant of the second current in the region by utilizing a complete impedance formula;
and a correlation coefficient solving module: the method is used for analyzing and expressing the transmission line current by utilizing a series of unknown coefficients related to the second current, the first current and the third current; adopting an auxiliary line with the same parameters as the original line but the length of the auxiliary line is only six times of the height, simulating the auxiliary line by using full-wave software to obtain the simulation current of the auxiliary line, and solving a series of unknown coefficients related to the second current, the first current and the third current in the original line by using the simulation current of the auxiliary line;
and the full line current solving module is used for: the method is used for correcting the propagation constant and a series of unknown coefficients obtained by using a complete impedance formula to obtain the high-frequency coupling current of the transmission line.
It will be appreciated by those skilled in the art that embodiments of the present invention may be provided as a method, system, or computer program product. Accordingly, the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flowchart illustrations and/or block diagrams, and combinations of flows and/or blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
Finally, it should be noted that: the foregoing embodiments are merely for illustrating the technical aspects of the present invention and not for limiting the scope thereof, and although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those skilled in the art that various changes, modifications or equivalents may be made to the specific embodiments of the present invention after reading the present invention, and these changes, modifications or equivalents are within the scope of the invention as defined in the appended claims.
Claims (8)
1. The high-frequency coupling current calculation method for the high-precision transmission line is characterized by comprising the following steps of:
step one: dividing the multi-conductor transmission line into a first region, a second region and a third region according to the transmission line height in the original line by utilizing an asymptotic theory and a classical transmission line model, wherein the first region is a left end region, the second region is a middle region and the third region is a right end region;
step two: correcting the propagation constant of the second current in the region by using a complete impedance formula;
in the second step, the propagation constant of the second current in the region is corrected by using a complete impedance formula;
the representation of the area two current is as follows:
in the formula ：I-transmission line current;
-line axial coordinates;T-a diagonal transformation matrix; />
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
the propagation constant is expressed as the product of impedance and admittance, and the impedance matrix and the admittance matrix are solved as follows, specifically:
wherein: z-an impedance matrix;j-imaginary units;ω-angular frequency;
-magnetic permeability; />
-a wiremAnd wirenIs a distance of (2);d m -a wiremIs of a height of (2);d n -a wirenIs of a height of (2);y-integrating the variables; />
—— and yA related function;
wherein ,
the expression is adopted as follows:
in the formula ：
-ground conductivity; />
-ground relative permittivity; />
-dielectric constant of air;
the admittance matrix is expressed by the following formula:
in the formula ：Y-admittance matrix;C-a capacitive matrix;L-an inductance matrix;
the inductance matrix is expressed as:
the propagation constant is represented by the product of impedance and admittance:
in the formula ,
-a propagation constant of the first transmission line; />
-a propagation constant of the second transmission line;N-a number of multi-conductor transmission lines; />
-firstNPropagation constant of the root transmission line;
step three: analyzing and expressing the current of the transmission line by using a series of unknown coefficients related to the second current, the first current and the third current; adopting an auxiliary line with the same parameters as the original line but the length of the auxiliary line is only six times of the height, simulating the auxiliary line by using full-wave software to obtain the simulation current of the auxiliary line, and solving a series of unknown coefficients related to the second current, the first current and the third current in the original line by using the simulation current of the auxiliary line;
step four: and (3) obtaining the high-frequency coupling current of the transmission line by using the propagation constant corrected by the complete impedance formula in the second step and a series of unknown coefficients obtained in the third step.
2. The method of claim 1, wherein in the first step, three regions of the multi-conductor transmission line are divided according to the transmission line heights: region one: 0. is less than or equal tox ≤ 2hAnd (2) a second area: 2h < x< L-2hAnd region three:L-2h ≤ x ≤ L, wherein ,xas the line axial coordinate,hfor the height of the transmission line,Lis the length of the transmission line.
3. The method for calculating high-frequency coupling current of high-precision transmission line according to claim 1, wherein in the third step, the transmission line current is expressed by analyzing a series of unknown coefficients related to the second current, the first current and the third current, specifically as follows:
the expression of the region two current is:
in the formula ：T-a diagonal transformation matrix;
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current; />
——NAn array of order units,Nthe number of transmission lines; />
-a reflection coefficient associated with region one; />
-a reflection coefficient associated with region three; />
-a voltage source coefficient associated with region one; />
-a voltage source coefficient associated with region three;
the expressions of the first current and the third current are:
in the formula ：
-region one and reflection related unknown coefficients;/>
-unknown coefficients of region three and reflection correlation; />
-an unknown coefficient associated with the first region and the voltage source; />
-region three, an unknown coefficient related to the voltage source;
and adopting an auxiliary line with the same parameters as the original line and the length of only six times of the height, simulating the auxiliary line by using full-wave software, and carrying the obtained current solution of the auxiliary line into the expressions of the first current, the second current and the third current, so as to obtain specific values of a series of unknown coefficients related to the second current, the first current and the third current in the original line.
4. The method for calculating high-frequency coupling current of high-precision transmission line according to claim 3, wherein in the fourth step, a specific value of high-frequency coupling current of transmission line is obtained by using the propagation constant corrected by the complete impedance formula in the second step and a series of unknown coefficients obtained in the third step;
the calculation formula of the high-frequency coupling current of the transmission line is as follows:
5. a high-precision transmission line high-frequency coupled current computing system, comprising:
and a current solving module: the multi-conductor transmission line is divided into a first region, a second region and a third region according to the transmission line height in an original line by utilizing an asymptotic theory and a classical transmission line model, wherein the first region is a left end region, the second region is a middle region and the third region is a right end region;
propagation constant correction module: the method is used for correcting the propagation constant of the second current in the region by utilizing a complete impedance formula;
in the propagation constant correction module, a complete impedance formula is utilized to correct the propagation constant of the second current in the region;
the representation of the area two current is as follows:
in the formula ：I-transmission line current;
-line axial coordinates;T-a diagonal transformation matrix; />
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current;
the propagation constant is expressed as the product of impedance and admittance, and the impedance matrix and the admittance matrix are solved as follows, specifically:
wherein: z-an impedance matrix;j-imaginary units;ω-angular frequency;
-magnetic permeability; />
-a wiremAnd wirenIs a distance of (2);d m -a wiremIs of a height of (2);d n -a wirenIs of a height of (2);y-integrating the variables; />
—— and yA related function;
wherein ,
the expression is adopted as follows:
in the formula ：
-ground conductivity; />
-ground relative permittivity; />
-dielectric constant of air;
the admittance matrix is expressed by the following formula:
in the formula ：Y-admittance matrix;C-a capacitive matrix;L-an inductance matrix;
the inductance matrix is expressed as:
the propagation constant is represented by the product of impedance and admittance:
in the formula ,
-a propagation constant of the first transmission line; />
-a propagation constant of the second transmission line;N-a number of multi-conductor transmission lines; />
-firstNPropagation constant of the root transmission line;
and a correlation coefficient solving module: the method is used for analyzing and expressing the transmission line current by utilizing a series of unknown coefficients related to the second current, the first current and the third current; adopting an auxiliary line with the same parameters as the original line but the length of the auxiliary line is only six times of the height, simulating the auxiliary line by using full-wave software to obtain the simulation current of the auxiliary line, and solving a series of unknown coefficients related to the second current, the first current and the third current in the original line by using the simulation current of the auxiliary line;
and the full line current solving module is used for: the method is used for correcting the propagation constant and a series of unknown coefficients obtained by using a complete impedance formula to obtain the high-frequency coupling current of the transmission line.
6. The high-precision transmission line high-frequency coupled current computing system according to claim 5, wherein in the current solving module, three regions of the multi-conductor transmission line are divided according to transmission line heights: region one: 0. is less than or equal tox ≤ 2hAnd (2) a second area: 2h < x< L-2hAnd region three:L-2h ≤ x ≤ L, wherein ,xas the line axial coordinate,hfor the height of the transmission line,Lis the length of the transmission line.
7. The high-precision transmission line high-frequency coupling current computing system according to claim 5, wherein the correlation coefficient solving module uses a series of unknown coefficients related to a second current, a first current and a third current to analyze and express the transmission line current, and the method is as follows:
the expression of the region two current is:
in the formula ：T-a diagonal transformation matrix;
-propagation constant; />
-forward travelling wave current; />
-counter-travelling wave current; />
——NAn array of order units,Nthe number of transmission lines; />
-a reflection coefficient associated with region one; />
-a reflection coefficient associated with region three; />
-a voltage source coefficient associated with region one; />
-a voltage source coefficient associated with region three;
the expressions of the first current and the third current are:
in the formula ：
-region one and reflection related unknown coefficients; />
-unknown coefficients of region three and reflection correlation; />
-an unknown coefficient associated with the first region and the voltage source; />
-region three, an unknown coefficient related to the voltage source;
and adopting an auxiliary line with the same parameters as the original line and the length of only six times of the height, simulating the auxiliary line by using full-wave software, and carrying the obtained current solution of the auxiliary line into the expressions of the first current, the second current and the third current, so as to obtain specific values of a series of unknown coefficients related to the second current, the first current and the third current in the original line.
8. The high-precision transmission line high-frequency coupling current calculation system according to claim 7, wherein in the all-line current solving module, a specific value of the high-frequency coupling current of the transmission line is obtained by using the propagation constant corrected by the complete impedance formula and a series of unknown coefficients obtained;
the calculation formula of the high-frequency coupling current of the transmission line is as follows:
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