A method and related device for measuring distributed parameters of multi-circuit asymmetric transmission lines

Abstract

The present invention relates to the technical field of electric variable measurement, and in particular to a method for measuring distributed parameters of a multi-circuit asymmetric transmission line and a related device, wherein the method comprises: obtaining zero-sequence voltage and zero-sequence current at both ends of the transmission line to be measured and the length of the transmission line to be measured; obtaining a transmission line model corresponding to the transmission line to be measured; calculating a voltage phase mode transformation matrix, a current phase mode transformation matrix, a hyperbolic sine matrix and a hyperbolic cosine matrix according to the transmission line model, the zero-sequence voltage and the zero-sequence current; calculating an impedance matrix of the transmission line to be measured according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length; and calculating an admittance matrix of the transmission line to be measured according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length, thereby improving the accuracy of distributed parameter measurement and solving the technical problem of low accuracy of distributed parameter measurement of existing transmission lines.

Description

Technical Field

[0001] The present invention relates to the technical field of electric variable measurement, and in particular to a method for measuring distributed parameters of a multi-circuit asymmetric power transmission line and a related device. Background Art

[0002] During the normal operation of the power system, the parameter characteristics of the transmission line play an important role in the stable operation of the entire system. When the power system is in a three-phase symmetrical operation state, the equivalent circuit of the overhead transmission line can be simplified to a single-phase circuit. This single-phase circuit contains key components such as the resistance, reactance (which is essentially related to inductance), ground conductance and susceptance (equivalent to capacitance) of the conductor. Among them, resistance mainly reflects the loss of active power during the transmission process, reactance is closely related to the magnetic field effect generated by the current-carrying conductor, and susceptance reflects the electric field effect around the charged conductor. In the actual design and operation of transmission lines, the conductivity parameter is usually small, which is mainly affected by insulator leakage and corona phenomenon. In order to avoid the adverse effects of corona phenomenon on transmission lines, a series of measures will be taken in the actual line design process, which makes the conductance value extremely small and can be ignored in many cases. Although conductance can be ignored in some cases, the power frequency parameters such as resistance, reactance and susceptance constitute the basic elements of the power system model as a whole. They have a vital impact on the accuracy of key tasks such as power flow calculation, relay protection configuration, transient stability analysis and fault location in the power system. Therefore, obtaining accurate transmission line parameters is of great significance to ensure the safe and stable operation of the power grid. When building a modern power system, ensuring the accuracy of transmission line parameter measurement has become an extremely important task.

[0003] In the current power system, due to factors such as transmission distance, construction cost and construction difficulty, most high-voltage transmission lines cannot achieve complete three-phase transposition, resulting in asymmetric parameters between three-phase transmission lines. The existing transmission line parameter measurement method generally uses the symmetrical component method to decompose the line parameters, but the symmetrical component method cannot achieve complete decoupling of asymmetric transmission line parameters, thereby reducing the measurement accuracy. Summary of the invention

[0004] The present invention provides a method and a related device for measuring distributed parameters of a multi-circuit asymmetric power transmission line, which are used to solve the technical problem of low measurement accuracy of distributed parameters of existing power transmission lines.

[0005] The present invention provides a method for measuring distributed parameters of a multi-circuit asymmetric power transmission line, comprising:

[0006] Obtaining the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested;

[0007] Obtaining a transmission line model corresponding to the transmission line to be tested;

[0008] According to the transmission line model, the zero-sequence voltage and the zero-sequence current, a voltage phase mode transformation matrix, a current phase mode transformation matrix, a hyperbolic sine matrix and a hyperbolic cosine matrix are calculated;

[0009] Calculate the impedance matrix of the transmission line to be tested according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length;

[0010] The admittance matrix of the transmission line to be tested is calculated based on the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0011] Optionally, the calculation formula of the impedance matrix is:

[0012]

[0013] is the impedance matrix, is the voltage phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length.

[0014] Optionally, the calculation formula of the admittance matrix is:

[0015]

[0016] is the admittance matrix, is the current phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length.

[0017] Optionally, obtaining the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested includes:

[0018] Obtaining a target operating mode corresponding to the transmission line to be tested;

[0019] Under the target operation mode, the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested are measured.

[0020] Optionally, the transmission line model includes a first transmission line sub-model and a second transmission line sub-model; and the voltage phase mode transformation matrix, the current phase mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix are calculated according to the transmission line model, the zero-sequence voltage, and the zero-sequence current, including:

[0021] Determine a first chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line sub-model, and determine a second chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line sub-model;

[0022] Calculating the eigenvector of the first chain parameter submatrix to obtain the current phase mode transformation matrix;

[0023] Calculating the eigenvector of the second chain parameter submatrix to obtain the voltage phase mode transformation matrix;

[0024] Calculate the eigenvalue of the first chain parameter submatrix to obtain the hyperbolic cosine matrix, or calculate the eigenvalue of the second chain parameter submatrix to obtain the hyperbolic cosine matrix;

[0025] The hyperbolic sine matrix is ​​determined according to the hyperbolic cosine matrix.

[0026] Optionally, determining a first chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line sub-model includes:

[0027] Inputting the zero-sequence voltage and the zero-sequence current into the first transmission line sub-model, and outputting a first chain parameter matrix;

[0028] The submatrix located in the second row and the second column of the first chain parameter matrix is ​​used as the first chain parameter submatrix.

[0029] Optionally, determining a second chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line sub-model includes:

[0030] Inputting the zero-sequence current and the zero-sequence voltage into the second transmission line sub-model, and outputting a second chain parameter matrix;

[0031] The submatrix located in the first row and first column of the second chain parameter matrix is ​​used as the second chain parameter submatrix.

[0032] Optionally, the method further comprises:

[0033] Determining the self-impedance parameter and the mutual-impedance parameter of the transmission line to be tested according to the impedance matrix;

[0034] According to the admittance matrix, the self-admittance parameter and the mutual-admittance parameter of the transmission line to be tested are determined.

[0035] Another aspect of the present invention provides a device for measuring distributed parameters of a multi-circuit asymmetric power transmission line, the device comprising:

[0036] A first acquisition module is used to acquire the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested;

[0037] A second acquisition module is used to acquire a transmission line model corresponding to the transmission line to be tested;

[0038] A first calculation module is used to calculate a voltage phase mode transformation matrix, a current phase mode transformation matrix, a hyperbolic sine matrix, and a hyperbolic cosine matrix according to the transmission line model, the zero-sequence voltage, and the zero-sequence current;

[0039] A second calculation module is used to calculate the impedance matrix of the transmission line to be tested according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length;

[0040] The third calculation module is used to calculate the admittance matrix of the transmission line to be tested according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0041] Another aspect of the present invention provides an electronic device, the device comprising a processor and a memory;

[0042] The memory is used to store program codes and transmit the program codes to the processor;

[0043] The processor is used to execute the method as described above according to the instructions in the program code.

[0044] It can be seen from the above technical solutions that the present invention has the following advantages:

[0045] The present invention achieves the acquisition of the zero-sequence voltage and zero-sequence current at both ends of the multi-circuit asymmetric transmission line to be tested, and the acquisition of the length of both ends of the multi-circuit asymmetric transmission line to be tested by acquiring the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested; and achieves the acquisition of the transmission line model by acquiring the transmission line model corresponding to the transmission line to be tested; and based on the phase mode transformation theory and the chain parameter distance theory, the present invention calculates the voltage phase mode transformation matrix, the current phase mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix according to the transmission line model, the zero-sequence voltage and the zero-sequence current, thereby achieving The complete decoupling of the asymmetric transmission line parameters improves the parameter measurement accuracy of multiple asymmetric transmission lines; and according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length, the impedance matrix of the transmission line to be measured is calculated, and according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length, the admittance matrix of the transmission line to be measured is calculated, and the measurement of the admittance matrix and the impedance matrix of the transmission line to be measured is realized, thereby providing an accurate data source for the calculation of the distributed parameters of multiple asymmetric transmission lines, and improving the accuracy of the distributed parameters of the transmission lines. And the embodiment of the present invention improves the efficiency of parameter measurement of multiple asymmetric transmission lines by calculating the impedance matrix and the admittance matrix separately, especially when facing the calculation of the distributed parameters of multiple asymmetric transmission lines, the calculation speed is faster and the efficiency is higher. Therefore, the measurement method provided by the present invention solves the technical problem of low measurement accuracy of the distributed parameters of the existing transmission lines, and improves the measurement accuracy and measurement efficiency of asymmetric transmission lines. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0047] Figure 1 A flowchart of a method for measuring distributed parameters of a multi-circuit asymmetric transmission line provided by an embodiment of the present invention;

[0048] Figure 2 Another step flow chart of a method for measuring distributed parameters of a multi-circuit asymmetric transmission line provided by an embodiment of the present invention;

[0049] Figure 3 A schematic diagram of the structure of a distributed parameter model of a multi-circuit asymmetric transmission line provided by an embodiment of the present invention;

[0050] Figure 4 A simulation model diagram of a multi-circuit asymmetric transmission line provided for an application example of the present invention;

[0051] Figure 5 A schematic diagram showing how the maximum value of the relative deviation of line parameters of a multi-circuit asymmetric transmission line measured at different line lengths varies with the length of the transmission line provided by the application example of the present invention;

[0052] Figure 6 A schematic diagram showing how the average value of relative deviations of line parameters of a multi-circuit asymmetric power transmission line measured at different line lengths varies with the length of the transmission line provided by an embodiment of the present invention;

[0053] Figure 7 A schematic structural diagram of a device for measuring distributed parameters of a multi-circuit asymmetric transmission line provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In actual projects, due to the different installation conditions, arrangement methods, material models and voltage levels of transmission lines, there is asymmetry in the parameters of transmission lines. The non-transposition of the three-phase transmission line will lead to asymmetric parameters of the three-phase line of the system, which will lead to asymmetry of the three-phase current and voltage during normal operation, thus affecting the normal operation of the system's relay protection devices and other equipment. In principle, high-voltage transmission lines should adopt transposition measures to reduce the asymmetry of current and voltage during normal operation of the power system. However, design and operation experience show that complete transposition of high-voltage lines will weaken the electrical and mechanical strength of the lines and increase the cost of construction and operation and maintenance. In addition, in some areas where the line corridors are particularly tight, some lines may not have the conditions to adopt a complete transposition installation method. There are complex electromagnetic and electrostatic coupling relationships between the phases of each circuit and between the circuits of the multi-circuit transmission line on the same tower. Even if the single-circuit line is a balanced line with uniform transposition, it will be difficult to achieve complete symmetry when multiple circuits are erected due to different conductor arrangements, phase sequence arrangements and transposition directions. Therefore, it is difficult for the existing power system to achieve complete transposition of the three phases, resulting in parameter asymmetry between the three-phase transmission lines. The existing transmission line measurement methods generally use the symmetrical component method to decompose the line parameters. However, the symmetrical component method cannot achieve complete decoupling of asymmetrical transmission line parameters, thereby reducing the measurement accuracy.

[0055] Therefore, in order to further improve the accuracy of transmission line parameter measurement, it is necessary to consider the three-phase line phase separation. The multi-circuit asymmetric transmission line distributed parameter measurement method based on phase mode transformation theory and link parameter matrix proposed in the present invention solves the technical problem that the measurement accuracy of the multi-circuit asymmetric transmission line distributed parameter measurement method is affected, improves the accuracy and reliability of the transmission line zero-sequence distributed parameter measurement, has good robustness and noise resistance, and is particularly suitable for the measurement of multi-circuit transmission lines.

[0056] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the drawings in the embodiments of the present invention. Obviously, the embodiments described below 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.

[0057] See also Figure 1 The present invention provides a method for measuring distributed parameters of a multi-circuit asymmetric transmission line, comprising:

[0058] 101. Obtain the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested.

[0059] It should be noted that the transmission line to be tested refers to an asymmetric transmission line that requires distributed parameter measurement. The transmission line to be tested is a multi-loop asymmetric transmission line. Based on the asymmetry of the line parameters, each phase line is analyzed separately, and it can be seen that the multi-loop asymmetric transmission circuit can be regarded as a transmission system containing n conductors, where the value of n is consistent with the value of the number of loops. The length of the transmission line to be tested is the length of the conductor. In one example, the multi-loop asymmetric transmission lines are all laid in parallel.

[0060] The two ends of each line in the transmission line to be tested can be divided into a head end and a terminal end. This step collects the zero-sequence current at the head end, the zero-sequence voltage at the head end, the zero-sequence current at the terminal end, and the zero-sequence voltage at the terminal end of each line of the transmission line to be tested. Among them, the terminal end refers to the grounding end, and the head end refers to the end connected to the measuring power supply. Among them, the measuring power supply is used to provide a source of electric energy for measuring the zero-sequence voltage and zero-sequence current of the transmission line to be tested. In one embodiment, the zero-sequence voltage and zero-sequence current at both ends of each line of the transmission line to be tested are obtained under different zero-sequence measurement methods, which are in the form of phasors.

[0061] 102. Obtain a transmission line model corresponding to the transmission line to be tested.

[0062] It should be noted that the transmission line model is pre-built and stored. After the transmission line to be tested is determined, the number of transmission lines to be tested can be determined to obtain the transmission line model corresponding to the number of transmission lines to be tested as the transmission line model corresponding to the transmission line to be tested.

[0063] In one example, the construction step of the transmission line model may include: constructing an initial transmission line equation of a three-phase transmission line containing n conductors based on a line impedance expression and a line admittance expression of a multi-loop asymmetric transmission line, wherein the initial transmission line equation is in the form of a matrix. Then, according to the phase-mode transformation theory, the coefficient matrix and the phasor matrix in the initial transmission line equation are equivalently transformed using the transformation matrix, the coupling relationship between the original phasors is released, and the original phasors are transformed into new modules that are independent of each other, and then based on the new modules and the chain parameter matrix, a transformation is performed to obtain the final expression of the transmission line model.

[0064] 103. According to the transmission line model, zero-sequence voltage and zero-sequence current, the voltage phase-mode transformation matrix, current phase-mode transformation matrix, hyperbolic sine matrix and hyperbolic cosine matrix are calculated.

[0065] It should be noted that the transmission line model is in the form of a matrix, which feeds back the relationship between the zero-sequence voltage and zero-sequence current at the head end of the line and the zero-sequence voltage and zero-sequence current at the end of the line. Among them, the zero-sequence voltage and zero-sequence current at the head end of the line constitute the first group of matrices, and the zero-sequence voltage and zero-sequence current at the end of the line constitute the second group of matrices. The relationship fed back by the transmission line model is: the product of the coefficient matrix and the second group of matrices is equal to the first group of matrices, wherein the coefficient matrix is ​​composed of a voltage phase-mode transformation matrix, a current phase-mode transformation matrix, a hyperbolic sine matrix, and a hyperbolic cosine matrix. Therefore, in actual application, the zero-sequence voltage and zero-sequence current at the head end of the line and the zero-sequence voltage and zero-sequence current at the end of the line are input into the transmission line model to solve the coefficient matrix, and the voltage phase-mode transformation matrix, the current phase-mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix can be obtained.

[0066] 104. The impedance matrix of the transmission line to be tested is calculated based on the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0067] It should be noted that the impedance matrix calculated in this step is an impedance matrix under unit length. The impedance matrix is ​​used to indicate the impedance characteristics of multiple asymmetric transmission lines.

[0068] In one embodiment, the impedance matrix is ​​calculated as follows:

[0069]

[0070] is the impedance matrix, is the voltage phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length.

[0071] It should be noted that in this step, the voltage phase transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length are input into the impedance matrix calculation formula to calculate the impedance matrix.

[0072] 105. The admittance matrix of the transmission line to be tested is calculated based on the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0073] It should be noted that the admittance matrix calculated in this step is an admittance matrix under unit length. The admittance matrix is ​​used to indicate the admittance characteristics of multiple asymmetric transmission lines.

[0074] In one embodiment, the calculation formula of the admittance matrix is:

[0075]

[0076] is the admittance matrix, is the current phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length.

[0077] It should be noted that in this step, the voltage phase transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length are input into the admittance matrix calculation formula to calculate the admittance matrix.

[0078] This embodiment obtains the zero-sequence voltage and zero-sequence current at both ends of the multi-loop asymmetric transmission line to be tested, and obtains the length of the multi-loop asymmetric transmission line to be tested by obtaining the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the multi-loop asymmetric transmission line to be tested; and obtains the transmission line model corresponding to the transmission line to be tested, thereby obtaining the transmission line model; and this embodiment is based on the phase mode transformation theory and the chain parameter distance theory, according to the transmission line model, zero-sequence voltage and zero-sequence current, calculates the voltage phase mode transformation matrix, the current phase mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix, thereby achieving the asymmetric transmission line The complete decoupling of the line parameters improves the parameter measurement accuracy of multi-loop asymmetric transmission lines; and according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length, the impedance matrix of the transmission line to be measured is calculated, and according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length, the admittance matrix of the transmission line to be measured is calculated, and the measurement of the admittance matrix and the impedance matrix of the transmission line to be measured is realized, thereby providing an accurate data source for the calculation of the distributed parameters of the multi-loop asymmetric transmission lines, and by calculating the impedance matrix and the admittance matrix respectively, the efficiency of the parameter measurement of the multi-loop asymmetric transmission lines is improved. Therefore, the measurement method provided in this embodiment solves the technical problem of low measurement accuracy of the distributed parameters of the existing transmission lines, and improves the measurement accuracy and measurement efficiency of the asymmetric transmission lines.

[0079] It is understandable that step 101 and step 102 can be performed simultaneously or sequentially, and can be set according to actual needs. This embodiment takes sequential execution as an example. The same is true for step 104 and step 105.

[0080] See also Figure 2 , a method for measuring distributed parameters of a plurality of asymmetric transmission lines provided by an embodiment of the present invention comprises:

[0081] 201. Obtain the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested.

[0082] It should be noted that the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested can be measured synchronously by double-end synchronous measurement. Therefore, the measurement points can be set at the beginning and end of each line. The measured zero-sequence voltage and zero-sequence current are in the form of phasors. Before the measurement, the transmission line to be tested is put into a power-off state. In the power-off state, the measuring power supply is used to provide electric energy, and the zero-sequence voltage and zero-sequence current at both ends of each line are measured in turn.

[0083] Specifically, step 201 includes the following sub-steps:

[0084] S11. Obtain a target operating mode corresponding to the transmission line to be tested.

[0085] It should be noted that the purpose of obtaining the target operation mode is to ensure that the number of measured zero-sequence voltages and zero-sequence currents is sufficient to solve the coefficient matrix in the transmission line model. The target operation mode includes multiple operation modes, and each operation mode is independent of each other. Among them, the number of operation modes in the target operation mode is the same as the number of times in the transmission line to be tested. For example, when 4 asymmetric transmission lines are measured, 4 operation modes are obtained. Among them, it can be obtained by looking up the table based on the number of times of the transmission line to be tested. Each operation mode is shown in Table 1. In each operation mode, only the head end of one line is pressurized, and the pressurized lines are different in each operation mode. In practical applications, each line in the transmission line to be tested can be numbered first (for example, the first transmission line, the second transmission line, ..., the nth transmission line are defined), and then the zero-sequence voltage and zero-sequence current at both ends of each line are measured in turn according to the obtained operation mode.

[0086] Therefore, in this step, the corresponding target operation mode can be obtained by looking up a table according to the number of transmission lines to be tested.

[0087] It can be understood that the principle of this step is: by setting some voltage phasors or current phasors in the voltage and current phasor equations to zero through the short-circuit grounding and open-circuit suspension operation modes, the original equation group containing 2n equations can be transformed into two equation groups containing n equations respectively. For the solution operation of the equation group containing n equations, it is theoretically necessary to set n independent operation modes. Therefore, by synchronously measuring the voltage phasors and current phasors at the beginning and end of each line under each operation mode, it can be used to calculate the values ​​of each element in the coefficient matrix of the transmission line equation group.

[0088] Table 1

[0089]

[0090] S12. Under the target operation mode, measure the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested.

[0091] It should be noted that this step may adopt a double-end synchronous measurement method to measure the voltage phasors and current phasors at the head and end of each line in each operating mode in the target operating mode.

[0092] In one embodiment, the measuring device may be a synchronous measuring device. This is only an illustrative example and does not limit the device for obtaining the power parameters of each transmission line.

[0093] 202. Obtain a transmission line model corresponding to the transmission line to be tested.

[0094] 203. According to the transmission line model, zero-sequence voltage and zero-sequence current, the voltage phase-mode transformation matrix, current phase-mode transformation matrix, hyperbolic sine matrix and hyperbolic cosine matrix are calculated.

[0095] It should be noted that the transmission line model includes a first transmission line sub-model and a second transmission line sub-model.

[0096] The matrix expression of the first transmission line submodel is as follows:

[0097]

[0098] in, is the zero-sequence voltage at the beginning of the line, is the zero-sequence current at the beginning of the line, is the zero-sequence current at the end of the line, is the zero-sequence voltage at the end of the line.

[0099] The coefficient matrix is:

[0100]

[0101] represents the admittance matrix, Representation Matrix and matrix The square root of the eigenvalue of .

[0102] The matrix expression of the second transmission line submodel is as follows:

[0103]

[0104] in, is the zero-sequence voltage at the beginning of the line, is the zero-sequence current at the beginning of the line, is the zero-sequence current at the end of the line, is the zero-sequence voltage at the end of the line, Representation Matrix and matrix The square root of the eigenvalue of .

[0105] Specifically, step 203 includes the following sub-steps:

[0106] S31. Determine a first chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line sub-model, and determine a second chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line sub-model.

[0107] In one embodiment, the step of determining the first chain parameter submatrix includes:

[0108] S311, inputting the zero-sequence voltage and the zero-sequence current into the first transmission line sub-model, and outputting a first chain parameter matrix;

[0109] S312: Use the submatrix located in the second row and the second column of the first chain parameter matrix as the first chain parameter submatrix.

[0110] In one embodiment, the step of determining the second chain parameter submatrix includes:

[0111] S313, inputting the zero-sequence current and the zero-sequence voltage into the second transmission line sub-model, and outputting a second chain parameter matrix;

[0112] S314. Use the submatrix located in the first row and first column of the second chain parameter matrix as the second chain parameter submatrix.

[0113] S32. Calculate the eigenvector of the first chain parameter submatrix to obtain a current phase mode transformation matrix.

[0114] S33. Calculate the eigenvector of the second chain parameter submatrix to obtain a voltage phase mode transformation matrix.

[0115] S34. Calculate the eigenvalues ​​of the first chain parameter submatrix to obtain a hyperbolic cosine matrix, or calculate the eigenvalues ​​of the second chain parameter submatrix to obtain a hyperbolic cosine matrix.

[0116] It should be noted that the zero-sequence voltage and zero-sequence current at the head end and the zero-sequence voltage and zero-sequence current at the end are input into the first transmission line sub-model, and the first chain parameter matrix is ​​obtained by solving as follows:

[0117]

[0118] According to the above formula, the first chain parameter matrix contains four chain parameter sub-matrices, among which the first chain parameter sub-matrix is:

[0119]

[0120] Among them, the eigenvalues ​​of the first chain parameter submatrix are , whose eigenvectors form the matrix .

[0121] Therefore, by calculating the eigenvalues ​​and eigenvectors of the first chain parameter submatrix, the hyperbolic cosine matrix can be obtained and the current phase transformation matrix .

[0122] Similarly, the zero-sequence voltage and zero-sequence current at the head end and the zero-sequence voltage and zero-sequence current at the end are input into the second transmission line sub-model, and the second chain parameter matrix is ​​obtained as follows:

[0123]

[0124] Then the second chain parameter submatrix is ​​as follows:

[0125]

[0126] Among them, the eigenvalues ​​of the second chain parameter submatrix are , whose eigenvectors form the matrix .

[0127] Therefore, by calculating the eigenvalues ​​and eigenvectors of the second chain parameter submatrix, the hyperbolic cosine matrix can be obtained and voltage phase transformation matrix .

[0128] It can be seen from the above that the hyperbolic cosine matrix can be calculated by calculating the eigenvalues ​​of the first chain parameter submatrix, or by calculating the eigenvalues ​​of the second chain parameter submatrix.

[0129] S35. Determine a hyperbolic sine matrix according to the hyperbolic cosine matrix.

[0130] It should be noted that a hyperbolic sine matrix can be obtained by transforming a hyperbolic cosine matrix.

[0131] 204. The impedance matrix of the transmission line to be tested is calculated based on the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0132] 205. The admittance matrix of the transmission line to be tested is calculated based on the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0133] It should be noted that step 204 and step 205 may refer to step 104 to step 105, which will not be repeated here.

[0134] 206. According to the impedance matrix, determine the self-impedance parameters and mutual impedance parameters of the transmission line to be tested.

[0135] It should be noted that the impedance matrix includes self-impedance parameters and mutual impedance parameters, wherein the impedance matrix is ​​an n-order matrix, and n is the same as the number of circuits of the transmission line to be measured.

[0136] The diagonal elements in the impedance matrix represent the self-impedance parameters, which are the self-impedance parameters of the first line to the nth line in the transmission line to be tested. The non-diagonal elements in each row or column of the impedance matrix represent the mutual impedance parameters, which are the mutual impedance parameters of the first line to the nth line in the transmission line to be tested.

[0137] Therefore, after obtaining the impedance matrix, the self-impedance parameters and mutual impedance parameters of the transmission line to be tested can be determined according to the elements inside the impedance matrix.

[0138] 207. According to the admittance matrix, determine the self-admittance parameters and mutual-admittance parameters of the transmission line to be tested.

[0139] It should be noted that the admittance matrix includes self-admittance parameters and mutual-admittance parameters, wherein the admittance matrix is ​​a matrix with n rows and n columns, and n is the same as the number of the transmission line to be measured.

[0140] The diagonal elements in the admittance matrix represent self-admittance parameters, which are the self-admittance parameters of the first line to the nth line in the transmission line to be tested. The non-diagonal elements of each row or column in the admittance matrix represent mutual admittance parameters, which are the mutual admittance parameters of the first line to the nth line in the transmission line to be tested.

[0141] Therefore, after obtaining the admittance matrix, the self-admittance parameters and mutual-admittance parameters of the transmission line to be tested can be determined according to the elements inside the admittance matrix.

[0142] It can be understood that the self-impedance parameter obtained in this embodiment is the zero-sequence self-impedance distributed per unit length. The mutual impedance parameter is the zero-sequence mutual impedance distributed per unit length. The self-admittance parameter is the zero-sequence self-admittance distributed per unit length, and the mutual admittance parameter is the zero-sequence mutual admittance distributed per unit length.

[0143] From the above, it can be seen that the method for measuring distributed parameters of a multi-loop asymmetric transmission line provided by the embodiment of the present invention can effectively and accurately solve the self-impedance parameters, mutual impedance parameters, self-admittance parameters, and mutual admittance parameters of the multi-loop asymmetric transmission line, overcome the disadvantage of the traditional method based on the concentrated parameter model that the measurement of long lines causes a large measurement error, and can measure multiple zero-sequence parameters at one time, and the measurement accuracy is much higher than the traditional measurement method, meeting the actual design needs of the project. Therefore, by adopting the measurement method provided by the embodiment of the present invention, the measurement accuracy of the parameters of the multi-loop asymmetric transmission line can be effectively improved, and the technical problem of low measurement accuracy of the existing transmission line distributed parameter measurement can be solved.

[0144] In an application example, the construction principle of the transmission line model, the calculation principle of the impedance matrix and the admittance matrix in the embodiment of the present invention will be explained.

[0145] First, for a multi-circuit asymmetric transmission line, a line impedance parameter matrix can be used to indicate the impedance characteristics of the multi-circuit asymmetric transmission line, and an admittance parameter matrix can be used to indicate the admittance characteristics of the multi-circuit asymmetric transmission line. It can be understood that in the present invention, the line impedance parameter matrix is ​​called an impedance matrix, and the admittance parameter matrix is ​​called an admittance matrix.

[0146] Based on the above definition, the line impedance parameter matrix and the admittance parameter matrix of the multi-loop asymmetric transmission line can be constructed. Specifically, the line impedance parameter matrix of the multi-loop asymmetric transmission line is generated according to the unit length distributed zero-sequence self-impedance of each transmission line in the multi-loop asymmetric transmission line and the unit length distributed zero-sequence mutual impedance between each transmission line and the remaining transmission lines in the multi-loop asymmetric transmission line. The admittance parameter matrix of the multi-loop asymmetric transmission line is generated according to the unit length zero-sequence self-admittance of each transmission line and the unit length distributed zero-sequence mutual admittance between each transmission line and the remaining transmission lines in the multi-loop asymmetric transmission line.

[0147] In one example, Figure 3 Taking the distributed parameter model of the multi-circuit asymmetric transmission line shown in FIG. 1 as an example, the line impedance parameter matrix and the admittance parameter matrix of the multi-circuit asymmetric transmission line constructed based on the distributed parameter model can be shown as follows.

[0148]

[0149] in, represents the distributed zero-sequence self-impedance per unit length of the i-th transmission line, ,For example: The distributed zero-sequence self-impedance per unit length of the first transmission line can be expressed as The distributed zero-sequence self-impedance per unit length of the second transmission line can be expressed as: represents the distributed zero-sequence mutual impedance per unit length between the i-th transmission line and the j-th transmission line, where: .For example: It represents the distributed zero-sequence mutual impedance per unit length between the first transmission line and the second transmission line.

[0150] Among them, the line self-impedance parameter expression of multi-circuit asymmetric transmission lines is:

[0151]

[0152] in, is the self-resistance per unit length of the ith transmission line, is the self-inductance per unit length of the i-th transmission line.

[0153] The line mutual impedance parameter expression of multi-circuit asymmetric transmission lines is:

[0154]

[0155] in, is the mutual resistance per unit length between the i-th transmission line and the j-th transmission line, is the mutual inductance per unit length between the ith transmission line and the jth transmission line.

[0156] The line admittance parameter matrix of the constructed multi-circuit asymmetric transmission line can be shown as follows:

[0157]

[0158] in, represents the distributed zero-sequence self-admittance per unit length of the i-th transmission line, ,For example: The distributed zero-sequence self-admittance per unit length of the first transmission line can be expressed as The distributed zero-sequence self-admittance per unit length of the second transmission line can be expressed. represents the distributed zero-sequence mutual admittance per unit length between the ith transmission line and the jth transmission line, where: .For example: The distributed zero-sequence mutual admittance per unit length between the first transmission line and the second transmission line can be expressed.

[0159] Among them, the line self-admittance parameter expression of multi-circuit asymmetric transmission lines is:

[0160]

[0161] in, is the self-capacitance per unit length of the i-th transmission line.

[0162] The line mutual admittance parameter expression of multi-circuit asymmetric transmission lines is:

[0163]

[0164] in, is the mutual capacitance per unit length between the i-th transmission line and the j-th transmission line.

[0165] Secondly, according to Kirchhoff's principle, the line impedance parameter matrix and admittance parameter matrix are analyzed, and according to the phase model transformation and chain parameter matrix, the analysis of the voltage phasor and current phasor of each phase is simplified to avoid the coupling relationship between the phasors.

[0166] Specifically, ignoring high-order infinitesimals and using Kirchhoff's principle to analyze the line impedance parameter matrix and the admittance parameter matrix, the transmission line equation of the multi-loop asymmetric transmission line can be determined as shown in the first formula.

[0167] The first formula is:

[0168]

[0169]

[0170] In the formula, represents the distance from the end of the transmission line, Represents its microelement. , , , , , , , Respectively represent the transmission lines in microelement The first-terminal voltage phasor on , , , , , , , Respectively represent the transmission lines in microelement Voltage phasor across impedance; , , , , , , , Respectively represent the transmission lines in microelement The first-end current phasor on , , , , , , , Respectively represent the transmission lines in microelement Current phasor on admittance. , , , , , , , Respectively represent the transmission lines in microelement The self-impedance on Indicates transmission line With transmission lines Between microelement Mutual impedance on , , , , , , , Respectively represent the transmission lines in microelement The self-admittance on Indicates transmission line With transmission lines Between microelement The mutual admittance on .

[0171] According to the above formula, each transmission line has The terminal voltage phasor on , , , , , , , ; Each transmission line is in micro-element The terminal current phasor on can be expressed as , , , , , , , .

[0172] The transmission line equations of the three-phase transmission line containing n conductors in the first formula above are written in matrix form, and the derivatives of both sides of the transmission line equations are taken, and simplified according to the second formula, the third formula can be obtained. The second formula is the relationship between the line impedance parameter matrix and the admittance parameter matrix.

[0173] The second formula is:

[0174]

[0175] The third formula is:

[0176]

[0177]

[0178] in, Indicates that each wire is in the infinitesimal The column vector formed by the voltage phasor on is expressed as follows:

[0179]

[0180] Indicates that each wire is in the infinitesimal The column vector formed by the current phasor on is expressed as follows:

[0181]

[0182] is the line impedance parameter matrix, which is an n-dimensional matrix composed of the self-impedance and mutual impedance of each transmission line, and its expression is shown above.

[0183] is the admittance parameter matrix, which is an n-dimensional matrix composed of the self-admittance and mutual admittance of each transmission line, and its expression is shown above.

[0184] Perform phase transformation on both sides of the third formula, where the voltage phase transformation matrix is: , the current phase transformation matrix is The expressions of voltage phasor and current phasor before and after transformation are shown in the fourth formula.

[0185] The fourth formula is:

[0186]

[0187]

[0188] Voltage Phase Transformation Matrix The columns of the matrix The eigenvector of the current phase transformation matrix The columns of the matrix The feature vector of .

[0189] Substituting the fourth formula into the third formula, we obtain the fifth formula.

[0190] The fifth formula is:

[0191]

[0192]

[0193] By diagonalizing the coefficient matrix, the decoupling of the second-order differential equation group shown in the fifth formula is achieved, and a mutually independent second-order differential equation group is obtained as shown in the sixth formula.

[0194] The sixth formula is:

[0195]

[0196]

[0197] in, , , , For the matrix and matrix The characteristic value of .

[0198] For the group of second-order differential equations that are independent of each other after transformation as shown in the sixth formula, the expressions of the solutions of the voltage modulus and current modulus are shown in the seventh formula.

[0199] The seventh formula is:

[0200]

[0201]

[0202] represents the forward voltage modulus, represents the reverse voltage modulus, represents the forward current modulus, Represents the reverse current modulus.

[0203] Will , , , , , , , Represented in the form of matrices, we can get the corresponding , , , , , , , .

[0204] Specifically, Represents the column vector composed of voltage modulus, and the expression is as follows:

[0205]

[0206] Represents the column vector composed of the forward voltage modulus, and the expression is as follows:

[0207]

[0208] Represents the column vector composed of the reverse voltage modulus, and the expression is as follows:

[0209]

[0210] Represents the column vector composed of current modulus, and the expression is as follows:

[0211]

[0212] Represents the column vector composed of the forward current modulus, and the expression is as follows:

[0213]

[0214] Represents the column vector composed of the reverse current modulus, and the expression is as follows:

[0215]

[0216] represents the forward exponential matrix, which is expressed as follows:

[0217]

[0218] represents the inverse exponential matrix, and the expression is as follows:

[0219]

[0220] Through the voltage phase transformation matrix and the current phase transformation matrix By transforming the original voltage phasor and current phasor into the superposition of the forward modulus and the reverse modulus, the eighth formula can be obtained;

[0221] The eighth formula is:

[0222]

[0223]

[0224] According to the chain parameter matrix, the multi-circuit asymmetric transmission line containing n conductors is regarded as a 2n port, with n ports on the left and right sides. The transmission line equation is written for a three-phase transmission line containing n conductors, where the voltage variable and current variable are both phasors, and the expression is as follows:

[0225]

[0226] In the formula, Represented by voltage phasor and current phasor The matrix formed is expressed as follows:

[0227]

[0228] Represented by the impedance matrix and the admittance matrix The matrix formed is expressed as follows:

[0229]

[0230] For multiple asymmetric transmission lines, the solution of the transmission line equation of multiple asymmetric transmission lines can be obtained in the form of solution of state variable equation, as shown in the ninth formula.

[0231] The ninth formula is:

[0232]

[0233] In the formula, Represented by voltage phasor and current phasor The matrix formed by It is usually called the state transfer matrix; and in the ninth formula, It is called the chain parameter matrix, which is a 2n-dimensional matrix that represents the position of the transmission line axis. and location The relationship between the phase quantities is usually specified as .matrix Contains voltage phasors and current phasor , accordingly, the chain parameter matrix It contains 4 chain parameter sub-matrices, representing the voltage phasor and current phasor The relationship between two.

[0234] After a preliminary expansion of the ninth formula, the tenth formula is obtained.

[0235] The tenth formula is:

[0236]

[0237] In the formula, the chain parameter submatrix is an n-dimensional matrix.

[0238] make , ,in represents the total length of the transmission line. Substituting it into the tenth formula, we can get the chain parameter matrix of the entire transmission line: , and the voltage phasor at the line head end , Line head end current phasor Phase quantity with line end voltage , Line end current phasor The relationship between is shown in the eleventh formula;

[0239] The eleventh formula is:

[0240]

[0241] make , ,in represents the total length of the transmission line. Substituting it into the tenth formula, we can get the chain parameter matrix of the entire transmission line: , and the voltage phasor at the line head end , Line head end current phasor Phase quantity with line end voltage , Line end current phasor The relationship between is shown in the twelfth formula.

[0242] The twelfth formula is:

[0243]

[0244] Since the only difference between the solution of the state variable equation and the solution of the transmission line equation mentioned above is the variable and Therefore, some properties of the solution in the state variable equation are naturally valid in the solution of the transmission line equation, and the expression is as follows:

[0245]

[0246]

[0247]

[0248]

[0249] is the 2n-dimensional identity matrix.

[0250] Will Substitute into the eighth formula Expression, we can get the thirteenth formula.

[0251] The thirteenth formula is:

[0252]

[0253]

[0254] Will Substitute into the eighth formula The expression can be obtained as the fourteenth formula;

[0255] The fourteenth formula is:

[0256]

[0257]

[0258] Eliminate the reverse current modulus at the end of the line on the right side of the equation We can get:

[0259]

[0260] The voltage phasor at the end of the line is obtained and the line end current phasor The forward current modulus , the expression is as follows:

[0261]

[0262] Similarly, eliminating the forward current modulus at the end of the line on the right side of the equation We can get:

[0263]

[0264] The voltage phasor at the end of the line is obtained and the line end current phasor The reverse current modulus , the expression is as follows:

[0265]

[0266] Will Substitute into the eighth formula Expression, we can get the fifteenth formula.

[0267] The fifteenth formula is:

[0268]

[0269]

[0270] Will Substitute into the eighth formula The expression can be obtained as the sixteenth formula;

[0271] The sixteenth formula is:

[0272]

[0273]

[0274] Eliminate the reverse voltage modulus at the end of the line on the right side of the equation We can get:

[0275]

[0276] The voltage phasor at the end of the line is obtained and the line end current phasor The forward current modulus , the expression is as follows:

[0277]

[0278] Similarly, eliminating the forward current modulus at the end of the line on the right side of the equation We can get:

[0279]

[0280] The voltage phasor at the end of the line is obtained and the line end current phasor The reverse current modulus , the expression is as follows:

[0281]

[0282] The line end voltage phasor and the line end current phasor The modulus of the forward current at the end of the line , and the line end voltage phasor and the line end current phasor The reverse current modulus at the end of the line , substitute into the fourteenth formula The expression can be obtained by the voltage phasor at the end of the line and the line end current phasor The voltage phasor at the beginning of the line , as shown in the seventeenth formula.

[0283] The seventeenth formula is:

[0284]

[0285] The line end voltage phasor and the line end current phasor The modulus of the forward current at the end of the line , and the line end voltage phasor and the line end current phasor The reverse current modulus at the end of the line , substitute into the fourteenth formula The expression can be obtained by the voltage phasor at the end of the line and the line end current phasor The current phasor at the beginning of the line , as shown in the eighteenth formula.

[0286] The eighteenth formula is:

[0287]

[0288] Writing the seventeenth and eighteenth formulas in matrix form yields the nineteenth formula.

[0289] The nineteenth formula is:

[0290]

[0291] As shown above, the nineteenth formula is the voltage phasor at the line head end , Line head end current phasor Phase quantity with line end voltage , Line end current phasor The relationship between them, based on these matrix coefficients, the matrix hyperbolic function can be defined as shown in the twentieth formula.

[0292] The twentieth formula is:

[0293]

[0294]

[0295] In the chain parameter matrix of the eleventh formula, the chain parameter submatrix The diagonal matrix of the eigenvalues ​​of is , the matrix corresponding to the characteristic column vector is Therefore, the chain parameter submatrix The eigenvalues ​​and matrices of ,matrix There is a cosine hyperbolic relationship between the square roots of the eigenvalues ​​of The eigenvalues ​​and matrices of ,matrix The square root of the eigenvalue of There is a cosine hyperbolic function relationship as shown in the 19th formula, the chain parameter submatrix The matrix consisting of the eigenvalues ​​corresponding to the characteristic column vectors and the matrix The matrix formed by the eigenvalues ​​of the corresponding eigenvalue column vectors is the same, both of which are matrices .

[0296] The line end voltage phasor and the line end current phasor The modulus of the forward voltage at the end of the line , and the line end voltage phasor and the line end current phasor The reverse voltage modulus at the end of the line , substitute into the fourteenth formula Expression, we can get the 21st formula.

[0297] The twenty-first formula is:

[0298]

[0299] The line end voltage phasor and the line end current phasor The modulus of the forward voltage at the end of the line , and the line end voltage phasor and the line end current phasor The reverse voltage modulus at the end of the line , substitute into the fourteenth formula The expression can be obtained by the voltage phasor at the end of the line and the line end current phasor The current phasor at the beginning of the line , as shown in Formula 22.

[0300] The 22nd formula is:

[0301]

[0302] Writing the twenty-first and twenty-second formulas in matrix form yields the twenty-third formula.

[0303] The twenty-third formula is as follows:

[0304]

[0305] Among them, the 22nd formula is the voltage phasor at the head end of the line , Line head end current phasor Phase quantity with line end voltage , Line end current phasor The coefficient matrix corresponds to the chain parameter matrix shown in the eleventh formula, and the four sub-matrices constituting the coefficient matrix correspond to the four chain parameter sub-matrices in the chain parameter matrix respectively.

[0306] It can be understood that the coefficient matrix of the 22nd formula has similar properties as the 20th formula. For details, please refer to the description of the 20th formula, which will not be repeated here.

[0307] Among them, matching the coefficient matrix in the nineteenth formula with the chain parameter matrix, the following expression can be obtained:

[0308]

[0309]

[0310]

[0311]

[0312] Among them, matching the coefficient matrix in the twenty-third formula with the chain parameter matrix, the following expression can be obtained:

[0313]

[0314]

[0315]

[0316]

[0317] Substitute the expressions obtained by matching the coefficient matrix in the 19th formula and the 23rd formula into the following equations, and let , and the impedance matrix Expressions for the associated process impedance matrix and process admittance matrix.

[0318]

[0319]

[0320]

[0321]

[0322] Among them, the impedance matrix The expressions of the related process impedance matrix and process admittance matrix are shown in the twenty-fourth formula.

[0323] The twenty-fourth formula is:

[0324]

[0325] The impedance matrix The expression of is shown in the twenty-fifth formula;

[0326] The twenty-fifth formula is:

[0327]

[0328] Similarly, the admittance matrix The expression of is shown in the twenty-sixth formula.

[0329] The twenty-sixth formula is:

[0330]

[0331] According to the twenty-fifth formula and the twenty-sixth formula, the impedance matrix and the admittance matrix of the multi-loop asymmetric transmission line are calculated, and the self-impedance parameters, mutual impedance parameters, self-admittance parameters and mutual admittance parameters of the multi-loop asymmetric transmission line are obtained.

[0332] It is understandable that since the corona phenomenon does not occur in a normal operating line, the susceptance parameter can be ignored, that is, the distributed parameters of the multi-circuit asymmetric transmission line that need to be calculated do not need to calculate the susceptance parameter. The line parameters of each phase line obtained in the embodiment of the present invention.

[0333] Therefore, based on the principle description provided by the embodiment of the present invention, it can be known that the line impedance parameter matrix and the admittance parameter matrix of the multi-loop asymmetric transmission line can be constructed through the power parameters of the multi-loop asymmetric transmission line, and the line impedance parameter matrix and the admittance parameter matrix are solved. The line parameters of the multi-loop asymmetric transmission line are determined by combining the relationship between the phase mode transformation theory and the chain parameter matrix, and the self-impedance parameters, mutual impedance parameters, self-admittance parameters, and mutual admittance parameters of the multi-loop asymmetric transmission line are determined. The measurement method provided by the embodiment of the present invention achieves the technical effect of effectively solving the self-impedance parameters, mutual impedance parameters, self-admittance parameters, and mutual admittance parameters of the multi-loop asymmetric transmission line, and based on the method provided by the present invention, the admittance matrix and the impedance matrix can be calculated completely independently, so that when facing asymmetric transmission lines with more loops, the corresponding admittance matrix and impedance matrix can be obtained faster, and then the asymmetric transmission line distribution parameters can be obtained faster, which greatly improves the measurement efficiency and accuracy of the asymmetric transmission line distribution parameters.

[0334] In another application example, the influence of the earth loop line parameters can also be considered, the earth return resistance parameters are introduced, the distributed parameter model of multiple asymmetric transmission lines is established and the transmission line equations are written in parallel to further improve the accuracy of the distributed parameters of the asymmetric transmission lines.

[0335] In a simulation application example, electromagnetic transient simulation software can be used to establish a multi-circuit asymmetric transmission line simulation model to verify the effect of the embodiment of the present invention. Taking three circuits as an example, the established three-circuit asymmetric transmission line simulation model is as follows: Figure 4 Table 2 is an example table of theoretical values ​​of zero-sequence parameters per unit length of a transmission line, which reflects the theoretical values ​​of zero-sequence parameters per unit length of a transmission line.

[0336] Table 2 Example of theoretical values ​​of zero-sequence distribution line parameters for multi-circuit asymmetric transmission lines

[0337]

[0338] Optionally, the length of the transmission line is changed from 100 km to 600 km in simulation, and the maximum value of the relative deviation of the line parameter measured by the method provided in the embodiment of the present invention varies with the length of the transmission line as shown in FIG. Figure 5 As shown in FIG. 1 , the average value of the relative deviation of the line parameters measured by the method provided in the embodiment of the present invention varies with the length of the transmission line. Figure 6 shown.

[0339] Optionally, analyze Figure 5 , Figure 6 The following conclusions can be drawn:

[0340] The measurement accuracy of the measurement method of the embodiment of the present invention is not affected by the distance of the transmission line, because the measurement accuracy of the embodiment of the present invention takes into account the distribution effect of the line, and is therefore applicable to multi-circuit asymmetric transmission lines of any length. When the transmission line is long, a high measurement accuracy can still be maintained.

[0341] The measurement method of the embodiment of the present invention does not involve the theoretical values ​​of the line parameters and is therefore not limited by the theoretical values ​​of the line parameters. Therefore, the accuracy of the measurement method of the embodiment of the present invention is not affected by the degree of deviation of the theoretical values ​​of the line parameters. Therefore, the measurement method of the embodiment of the present invention is applicable to multi-circuit asymmetric transmission lines of any voltage level.

[0342] In the present invention, by collecting the power parameters of multiple asymmetric transmission lines (i.e., the head-end zero-sequence voltage and the head-end zero-sequence current of each transmission line, and the terminal zero-sequence voltage and the terminal zero-sequence current of each transmission line), a transmission line model is constructed, the line impedance parameter matrix and the admittance parameter matrix are solved, and the line parameters of the multiple asymmetric transmission lines are determined by combining the phase mode transformation theory and the relationship between the chain parameter matrix, thereby achieving the technical effect of effectively solving the self-impedance parameters, mutual impedance parameters, self-admittance parameters, and mutual admittance parameters of the multiple asymmetric transmission lines.

[0343] Figures 1 to 6 Any technical feature in the embodiment corresponding to any one of the items is also applicable to the embodiment of the present application. Figure 7 The corresponding embodiments will not be described in detail later.

[0344] See also Figure 7 The embodiment of the present invention further provides a device for measuring distributed parameters of a plurality of asymmetric power transmission lines, comprising:

[0345] A first acquisition module 701 is used to acquire the zero-sequence voltage and the zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested;

[0346] The second acquisition module 702 is used to acquire a transmission line model corresponding to the transmission line to be tested;

[0347] The first calculation module 703 is used to calculate the voltage phase mode transformation matrix, the current phase mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix according to the transmission line model, the zero-sequence voltage, and the zero-sequence current;

[0348] The second calculation module 704 is used to calculate the impedance matrix of the transmission line to be tested according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length;

[0349] The third calculation module 705 is used to calculate the admittance matrix of the transmission line to be tested according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length.

[0350] In a specific embodiment, the first acquisition module 701 includes:

[0351] A first acquisition unit, used to acquire a target operation mode corresponding to the transmission line to be tested;

[0352] The measuring unit is used to measure the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested under the target operation mode.

[0353] In a specific embodiment, the first calculation module 703 includes:

[0354] a first determining unit, configured to determine a first chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line submodel, and to determine a second chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line submodel;

[0355] A first calculation unit is used to calculate the eigenvector of the first chain parameter submatrix to obtain a current phase mode transformation matrix;

[0356] A second calculation unit is used to calculate the eigenvector of the second chain parameter submatrix to obtain a voltage phase mode transformation matrix;

[0357] A third calculation unit is used to calculate the eigenvalue of the first chain parameter submatrix to obtain a hyperbolic cosine matrix, or to calculate the eigenvalue of the second chain parameter submatrix to obtain a hyperbolic cosine matrix;

[0358] The second determining unit is used to determine the hyperbolic sine matrix according to the hyperbolic cosine matrix.

[0359] In a specific embodiment, the first determination unit is specifically used to input the zero-sequence voltage and zero-sequence current into the first transmission line sub-model, and output a first chain parameter matrix; and use the sub-matrix located in the second row and second column of the first chain parameter matrix as the first chain parameter sub-matrix.

[0360] In a specific embodiment, the first determination unit is specifically used to input the zero-sequence current and zero-sequence voltage into the second transmission line sub-model, and output a second chain parameter matrix; and use the sub-matrix located in the first row and first column of the second chain parameter matrix as the second chain parameter sub-matrix.

[0361] In a specific embodiment, it also includes:

[0362] A first determination module is used to determine the self-impedance parameter and the mutual impedance parameter of the transmission line to be tested according to the impedance matrix;

[0363] The second determination module is used to determine the self-admittance parameters and mutual-admittance parameters of the transmission line to be tested according to the admittance matrix.

[0364] In a specific embodiment, the present invention further provides an electronic device, the device including a processor and a memory;

[0365] The memory is used to store the program code and transmit the program code to the processor;

[0366] The processor is configured to execute the method of any of the above embodiments according to the instructions in the program code.

[0367] Those skilled in the art can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0368] In the several embodiments provided in the present application, it should be understood that the disclosed devices and methods can be implemented in other ways. For example, the device embodiments described above are only schematic. For example, the division of units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.

[0369] The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0370] In addition, each functional unit in each embodiment of the present invention may be integrated into one processing unit, or each functional unit may be physically separate, or two or more functional units may be integrated into one processing unit. The above integrated unit may be implemented in the form of hardware or in the form of software functional units.

[0371] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium, including several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods of each embodiment of the present invention. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (ROM, Read-Only Memory), random access memory (RAM, Random Access Memory), disk or optical disk, etc. Various media that can store program codes.

[0372] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0373] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for measuring distributed parameters of a multi-circuit asymmetric transmission line, characterized in that: include: Obtaining the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested; Obtaining a transmission line model corresponding to the transmission line to be tested; According to the transmission line model, the zero-sequence voltage and the zero-sequence current, a voltage phase mode transformation matrix, a current phase mode transformation matrix, a hyperbolic sine matrix and a hyperbolic cosine matrix are calculated; Calculate the impedance matrix of the transmission line to be tested according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length; Calculate the admittance matrix of the transmission line to be tested according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length; The calculation formula of the impedance matrix is: ； is the impedance matrix, is the voltage phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length; The calculation formula of the admittance matrix is: ； is the admittance matrix, is the current phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length; The transmission line model includes a first transmission line sub-model and a second transmission line sub-model; the voltage phase mode transformation matrix, the current phase mode transformation matrix, the hyperbolic sine matrix, and the hyperbolic cosine matrix are calculated according to the transmission line model, the zero-sequence voltage, and the zero-sequence current, including: Determine a first chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line sub-model, and determine a second chain parameter sub-matrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line sub-model; Calculating the eigenvector of the first chain parameter submatrix to obtain the current phase mode transformation matrix; Calculating the eigenvector of the second chain parameter submatrix to obtain the voltage phase mode transformation matrix; Calculate the eigenvalue of the first chain parameter submatrix to obtain the hyperbolic cosine matrix, or calculate the eigenvalue of the second chain parameter submatrix to obtain the hyperbolic cosine matrix; The hyperbolic sine matrix is ​​determined according to the hyperbolic cosine matrix.

2. The method according to claim 1, characterized in that The step of obtaining the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested comprises: Obtaining a target operating mode corresponding to the transmission line to be tested; Under the target operation mode, the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested are measured.

3. The method according to claim 1, characterized in that Determining a first chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line sub-model comprises: Inputting the zero-sequence voltage and the zero-sequence current into the first transmission line sub-model, and outputting a first chain parameter matrix; The submatrix located in the second row and the second column of the first chain parameter matrix is ​​used as the first chain parameter submatrix.

4. The method according to claim 3, characterized in that Determining the second link parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line sub-model comprises: Inputting the zero-sequence current and the zero-sequence voltage into the second transmission line sub-model, and outputting a second chain parameter matrix; The submatrix located in the first row and first column of the second chain parameter matrix is ​​used as the second chain parameter submatrix.

5. The method according to claim 1, characterized in that The method further comprises: Determining the self-impedance parameter and the mutual-impedance parameter of the transmission line to be tested according to the impedance matrix; According to the admittance matrix, the self-admittance parameter and the mutual-admittance parameter of the transmission line to be tested are determined.

6. A device for measuring distributed parameters of multiple asymmetric transmission lines, characterized in that: The device comprises: A first acquisition module is used to acquire the zero-sequence voltage and zero-sequence current at both ends of the transmission line to be tested and the length of the transmission line to be tested; A second acquisition module is used to acquire a transmission line model corresponding to the transmission line to be tested; A first calculation module is used to calculate a voltage phase mode transformation matrix, a current phase mode transformation matrix, a hyperbolic sine matrix, and a hyperbolic cosine matrix according to the transmission line model, the zero-sequence voltage, and the zero-sequence current; A second calculation module is used to calculate the impedance matrix of the transmission line to be tested according to the voltage phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length; A third calculation module, used for calculating the admittance matrix of the transmission line to be tested according to the current phase mode transformation matrix, the hyperbolic sine matrix, the hyperbolic cosine matrix and the length; The calculation formula of the impedance matrix is: ； is the impedance matrix, is the voltage phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length; The calculation formula of the admittance matrix is: ； is the admittance matrix, is the current phase transformation matrix, is a hyperbolic sine matrix, is the hyperbolic cosine matrix, is the length; The transmission line model includes a first transmission line sub-model and a second transmission line sub-model; The first calculation module includes: a first determining unit, configured to determine a first chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the first transmission line submodel, and to determine a second chain parameter submatrix according to the zero-sequence voltage, the zero-sequence current and the second transmission line submodel; A first calculation unit is used to calculate the eigenvector of the first chain parameter submatrix to obtain a current phase mode transformation matrix; A second calculation unit is used to calculate the eigenvector of the second chain parameter submatrix to obtain a voltage phase mode transformation matrix; A third calculation unit is used to calculate the eigenvalue of the first chain parameter submatrix to obtain a hyperbolic cosine matrix, or to calculate the eigenvalue of the second chain parameter submatrix to obtain a hyperbolic cosine matrix; The second determining unit is used to determine the hyperbolic sine matrix according to the hyperbolic cosine matrix.

7. An electronic device, characterized in that: The device comprises a processor and a memory; The memory is used to store program code and transmit the program code to the processor; The processor is configured to execute the method according to any one of claims 1 to 5 according to the instructions in the program code.

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