Line impedance online real-time accurate inversion calculation method, device, equipment and medium

Abstract

The embodiment of the present invention discloses a method for online real-time accurate inversion calculation of line impedance, including: selecting a number of measurement nodes of main lines and branches according to the section to be measured; forming a main line voltage matrix according to the measurement nodes of the main line; forming a branch line voltage matrix according to the measurement nodes of each branch line, and merging the two into a first voltage matrix; forming a second voltage matrix according to the voltage difference between the node at the outlet of the distribution network and the measurement node closest to it, and merging it and the first voltage matrix into a total voltage matrix; merging the total voltage matrix, the total current column vector, and the total admittance column vector into a total voltage matrix equation; used to determine the admittance of all sections to be measured, and then determine the corresponding impedance. This solution can calculate and invert more accurate line impedance online in real time, provide accurate line parameters and topology information for real-time setting of power grid protection constants and real-time power flow calculation, and support applications such as power grid planning, scheduling, operation control, and source-grid-load-storage interaction.

Description

Technical Field

[0001] The present invention relates to the field of power electronics technology, and in particular to a method, device, equipment and medium for online real-time accurate inversion calculation of line impedance. Background Art

[0002] The access of a large number of distributed new energy sources and diversified loads to the power grid requires the power grid to achieve multi-directional coordination and flexible interaction. The traditional power grid has shown problems of insufficient transparency and digitization, especially the distribution network structure is complex and the equipment is numerous. The grid topology and electrical and physical parameters need to be transparent in an urgent need to truly realize the digital twin power grid.

[0003] Current technical means usually use the method of measuring line impedance during power outages, which affects power supply reliability and places a large workload on the distribution network. There is no effective method to perceive the entire power grid in real time and accurately obtain line impedance online. Summary of the invention

[0004] Based on this, it is necessary to propose a method, device, equipment and medium for online real-time accurate inversion calculation of line impedance to address the above problems.

[0005] To achieve the above-mentioned purpose, the first aspect of the present application provides a method for online real-time accurate inversion calculation of line impedance, the method comprising:

[0006] Selecting several measuring nodes in the distribution network according to the section to be measured;

[0007] Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0008] Forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0009] A branch line voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes;

[0010] Combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0011] A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0012] Construct an admittance column vector according to the admittance of each section to be measured;

[0013] The first voltage matrix, the current column vector, and the admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance;

[0014] A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0015] The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0016] Determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0017] The corresponding impedance is determined according to the admittance of all the sections to be measured.

[0018] In some implementations, the selecting of a plurality of measurement nodes in the distribution network according to the section to be measured specifically includes:

[0019] Determine all monitoring nodes included in the segment to be tested;

[0020] Sorting all the monitoring nodes according to the direction of the distribution network line;

[0021] The head-end nodes or the terminal nodes among all the monitoring nodes after sorting are removed, and the remaining monitoring nodes are used as measurement nodes.

[0022] In some embodiments, the main line voltage matrix The elements of are: Where i=1 to n, n is the number of main line nodes, and j is 1 to n.

[0023] In some embodiments, the branch voltage matrix The elements of are: Among them, if the i node has a branch, then k=i, k is the total number of branches, i=1 to p, p is the number of branch line nodes, and j is 1 to p.

[0024] In some implementations, combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix specifically includes:

[0025] The main line voltage matrix is ​​combined with the diagonal line of the branch line voltage matrix of each branch line respectively to form the first voltage matrix.

[0026] In some embodiments, the elements of the current column vector are:

[0027] In some embodiments, each element of the admittance column vector is: i1 =Y(i-1.i).

[0028] In some implementations, the first voltage matrix equation is: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector.

[0029] In some embodiments, the second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured, including:

[0030] The voltage difference between the node at the main line outlet of the distribution network and the measurement node closest to it is expanded into a second voltage matrix in the second voltage matrix equation of 1*j, U11 is U0-U1, when j>1, U1j=0, and it is added as the first row of the first voltage matrix in the first voltage matrix equation to form the total voltage matrix in the total voltage matrix equation;

[0031] The outflow current at the node of the main line outlet in the second voltage matrix equation is Added as the first row of the current column vector in the first voltage matrix equation to form the total current column vector in the total voltage matrix equation;

[0032] The total voltage matrix, the admittance column vector, and the total current column vector constitute the total voltage matrix equation used for inverse calculation of the admittance of the section to be measured.

[0033] In some implementations, the total voltage matrix equation is: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector, The pressure difference between the node at the main line outlet and the closest measurement node, It is the outflow current of the node where the main line exits.

[0034] To achieve the above-mentioned purpose, the second aspect of the present application provides an online real-time accurate inversion calculation device for line impedance, the device comprising:

[0035] A selection module is used to select a number of measurement nodes in the distribution network according to the section to be measured;

[0036] The selection module is further used to determine the measurement nodes of the main line and the measurement nodes of each branch line;

[0037] A voltage module, used for forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0038] The voltage module is further used to form a branch line voltage matrix according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between every two adjacent measurement nodes;

[0039] The voltage module is further used to combine the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0040] A current module, used to form a current column vector according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0041] An admittance module, used for forming an admittance column vector according to the admittance of each section to be measured;

[0042] A calculation module, used for combining the first voltage matrix, the current column vector, and the admittance column vector to form a first voltage matrix equation for inverse calculation of the first admittance;

[0043] The calculation module is further used to form a second voltage matrix equation according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0044] The calculation module is further used to merge the second voltage matrix equation into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0045] The calculation module is further used to determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0046] The calculation module is further used to determine the corresponding impedance according to the admittance of all the segments to be measured.

[0047] To achieve the above-mentioned object, the third aspect of the present application provides a computer device, including a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the following steps:

[0048] Selecting several measuring nodes in the distribution network according to the section to be measured;

[0049] Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0050] Forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0051] A branch line voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes;

[0052] Combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0053] A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0054] Construct an admittance column vector according to the admittance of each section to be measured;

[0055] The first voltage matrix, the current column vector, and the admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance;

[0056] A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0057] The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0058] Determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0059] The corresponding impedance is determined according to the admittance of all the sections to be measured.

[0060] To achieve the above-mentioned purpose, the fourth aspect of the present application provides a computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the following steps:

[0061] Selecting several measuring nodes in the distribution network according to the section to be measured;

[0062] Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0063] Forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0064] A branch line voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes;

[0065] Combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0066] A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0067] Construct an admittance column vector according to the admittance of each section to be measured;

[0068] The first voltage matrix, the current column vector, and the admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance;

[0069] A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0070] The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0071] Determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0072] The corresponding impedance is determined according to the admittance of all the sections to be measured.

[0073] The embodiments of the present invention have the following beneficial effects:

[0074] In order to solve the problem of measuring the impedance of the entire power grid line in real time online without power outage, the present invention proposes a method for accurately measuring and reconstructing the line parameters of the distribution network online by using the voltage and current measured on the low-voltage side of the transformer, and selecting a number of measurement nodes in the distribution network according to the section to be measured; determining the total voltage matrix, the total current column vector, and the admittance column vector according to the measurement nodes, and merging them to form a total voltage matrix equation for inverse calculation of the admittance; reconstructing the distribution network according to the total voltage matrix equation, and calculating and inverting the accurate line impedance online in real time, providing accurate line parameters and topology information for real-time setting of power grid protection constants and real-time power flow calculation, supporting applications such as power grid planning, scheduling, operation control, and source-grid-load-storage interaction, and facilitating the construction of new power systems, and adding a second voltage matrix composed of the voltage difference between the outgoing node in the distribution network and the closest measurement node, so that the convergence is stronger and the line impedance calculated by online real-time inversion is more accurate. BRIEF DESCRIPTION OF THE DRAWINGS

[0075] 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 work.

[0076] in:

[0077] Figure 1 It is a schematic diagram of a flow chart of a method for online real-time accurate inversion calculation of line impedance in one embodiment;

[0078] Figure 2 This is an example diagram of the basic principle of network reconstruction in an embodiment;

[0079] Figure 3 A structural diagram of a distribution network in one embodiment;

[0080] Figure 4 A schematic diagram of the main line of a distribution network structure diagram in one embodiment;

[0081] Figure 5 A schematic diagram of a vector analysis simulation model for a distribution transformer in an embodiment;

[0082] Figure 6 A positive sequence circuit diagram of a distribution transformer in one embodiment;

[0083] Figure 7 A negative sequence circuit diagram of a distribution transformer in one embodiment;

[0084] Figure 8 It is a structural diagram of a device for online real-time accurate inversion calculation of line impedance in one embodiment;

[0085] Fig. 9 is a schematic diagram of the structure of a computer device in one embodiment;

[0086] Fig.10 Schematic diagram of the structure of a computer-readable storage medium in one embodiment. DETAILED DESCRIPTION

[0087] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0088] In the embodiment of the present application, a method for online real-time accurate inversion calculation of line impedance is provided. Figure 1 , Figure 1 The present invention is a flowchart of a method for online real-time accurate inversion calculation of line impedance in an embodiment; the principle of the present application is to reconstruct the distribution network using matrix equations and inversely calculate the impedance of the line, specifically: based on the vector voltage and current vector between two nodes, the line impedance between the nodes is calculated.

[0089] For example, according to Figure 2 The basic principle of network reconstruction is shown in the figure. Y1 and Y2 can be solved, and the corresponding line impedance between nodes can be calculated based on Y1 and Y2.

[0090] In the embodiment of the present application, the line impedance online real-time accurate inversion calculation method includes: Figure 1 Steps S1 to S12 are shown.

[0091] Step S1 selects several measurement nodes in the distribution network according to the section to be measured;

[0092] In some implementations, the selecting of a plurality of measurement nodes in the distribution network according to the section to be measured specifically includes:

[0093] Determine all monitoring nodes included in the segment to be tested;

[0094] Sorting all the monitoring nodes according to the direction of the distribution network line;

[0095] The head-end nodes or the terminal nodes among all the monitoring nodes after sorting are removed, and the remaining monitoring nodes are used as measurement nodes.

[0096] Step S2, determining a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0097] Step S3, forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0098] In some embodiments, the main line voltage matrix The elements of are: Where i=1 to n, n is the number of main line nodes, and j is 1 to n.

[0099] Step S4, forming a branch line voltage matrix according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between every two adjacent measurement nodes;

[0100] In some embodiments, the branch voltage matrix The elements of are:

[0101] Among them, if the i node has a branch, then k=i, k is the total number of branches, i=1 to p, p is the number of branch line nodes, and j is 1 to p.

[0102] Step S5, combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0103] In some implementations, merging the main line voltage matrix and the branch line voltage matrix into a first voltage matrix specifically includes:

[0104] The main line voltage matrix is ​​combined with the diagonal line of the branch line voltage matrix of each branch line respectively to form the first voltage matrix.

[0105] Specifically, the first element of the first row of the branch voltage matrix of the first branch is placed in the next column of the next row of the last element in the main voltage matrix;

[0106] Place the first element of the first row of the N-th branch voltage matrix in the remaining branches in the next column of the next row of the last element in the N-1-th branch voltage matrix;

[0107] Finally, the first voltage matrix is ​​constructed.

[0108] Step S6, forming a current column vector according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0109] In some embodiments, the elements of the current column vector are:

[0110] Specifically, the current column vector includes and Main line current column vector I 主 The elements of are: Where i = 1 to n, n is the number of nodes in the main line; the branch current column vector I 支k The elements of are: Where k is the branch line number, i=1 to p, and p is the number of branch line nodes.

[0111] Step S7, constructing an admittance column vector according to the admittance of each section to be measured;

[0112] In some embodiments, each element of the admittance column vector is: i1 =Y(i-1.i).

[0113] Specifically, the admittance column vector includes Y 主 and Y 支k , admittance column vector Y 主 The elements of are: Y i1=Y(i-1.i), where i=1 to n, n is the number of main line nodes; the admittance column vector Y 支k The elements of are: Where k is the branch line number, i=1 to p, and p is the number of branch line nodes.

[0114] Step S8, combining the first voltage matrix, current column vector, and admittance column vector to form a first voltage matrix equation for inverse calculation of admittance;

[0115] In some implementations, the first voltage matrix equation is: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector.

[0116] Specifically, the main line voltage matrix Branch voltage matrix Combined to form the first voltage matrix is the admittance column vector, is the current column vector.

[0117] Step S9, constructing a second voltage matrix equation according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0118] Step S10, merging the second voltage matrix equation into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0119] In some embodiments, the second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured, including:

[0120] The voltage difference between the node at the main line outlet of the distribution network and the measurement node closest to it is expanded into a second voltage matrix in the second voltage matrix equation of 1*j, U11 is U0-U1, when j>1, U1j=0, and it is added as the first row of the first voltage matrix in the first voltage matrix equation to form the total voltage matrix in the total voltage matrix equation;

[0121] The outflow current at the node of the main line outlet in the second voltage matrix equation is Added as the first row of the current column vector in the first voltage matrix equation to form the total current column vector in the total voltage matrix equation;

[0122] The total voltage matrix, the admittance column vector, and the total current column vector constitute the total voltage matrix equation used for inverse calculation of the admittance of the section to be measured.

[0123] It should be noted that the admittance column vector is composed of the admittance of each section to be measured, including the admittance between the node at the main line outlet in the second voltage matrix equation and the measurement node closest to it, so the admittance column vector does not need to increase one row, and the admittance column vector is the total admittance column vector.

[0124] In some implementations, the total voltage matrix equation is: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector, The pressure difference between the node at the main line outlet and the closest measurement node, It is the outflow current of the node where the main line exits.

[0125] It should be noted that: the first voltage matrix equation is a homogeneous linear equation group, and the total voltage matrix equation composed of merging the second voltage matrix equation into the first voltage matrix equation is a non-homogeneous linear equation group. With one more constraint equation, the calculated admittance and final impedance will be more accurate. If only the first voltage matrix equation is used, if the voltage measurement is wrong, it will cause inaccurate parameter calculation and it will be difficult to detect. With one more constraint equation, it is possible to determine whether the measurement data is wrong by calculating whether the matrix converges. In this way, problems in the online real-time inversion calculation of the line impedance can be discovered in time, and the inversion results will be more precise and accurate.

[0126] Specifically, the main line voltage matrix Branch voltage matrix Combined to form the first voltage matrix First voltage matrix and the second voltage matrix Combined to form the total voltage matrix, is the admittance column vector, and is the total current column vector.

[0127] In some embodiments, After obtaining the first voltage matrix, the first voltage matrix equation can be constructed Add one row as the first row to the first voltage matrix U and the current column vector I respectively, and the admittance column vector Y remains unchanged, wherein the added row of the first voltage matrix U is: At this time, the first voltage matrix U becomes a (n+1)*n matrix;

[0128] The current column vector I adds one row to the first row, and the added row At this time, the current column vector I becomes a (n+1)*1 matrix.

[0129] in is the voltage at the outlet, is the current at the outlet, For the main line node 1, which is the node voltage closest to the outgoing line, the following equation is obtained:

[0130]

[0131] In some embodiments, the following steps are used to construct

[0132]

[0133] Assume that the main line has m nodes, there are k branches, each branch has n nodes, then there are j=m+kn nodes in total.

[0134] The main line voltage matrix is ​​constructed as an m*m matrix, the main line current matrix is ​​constructed as an m*1 matrix, and the main line admittance matrix is ​​constructed as an m*1 matrix;

[0135] The voltage matrix of each branch is constructed as an n*n matrix, the current matrix I of each branch is constructed as an n*1 matrix, and the admittance matrix of each branch is constructed as an n*1 matrix.

[0136] according to Combine all main line matrices and branch line matrices to form U 底 ×Y all =I 底 , where U 底 is the j*j matrix, that is, the first voltage matrix, Y all is a j*1 matrix, that is, the admittance column vector; I 底 is a j*1 matrix, that is, the current column vector;

[0137] Construct the second voltage matrix U m0 is a 1*j matrix, the first element is The remaining elements are 0.

[0138] Will U m0 As the first line with U 底 Combined to form the complete total voltage matrix U all , at this time the total voltage matrix U all =(j+1)*j; the current at the outlet As the first line with I 底 Combined to form a complete current column vector Iall , at this time the current column vector I all is a (j+1)*1 matrix;

[0139] Write the matrix equation as U all Y all =I all get

[0140] Specifically, for example, the voltage matrix equation can be reconstructed as Figure 3 The distribution network structure shown in the figure, the voltage matrix equation is:

[0141] Step S11, determining the admittance of all the segments to be measured according to the voltage matrix equation;

[0142] Specifically, according to the voltage matrix equation After measuring the voltage and current of each node, we can calculate That is, the admittance of all segments to be measured.

[0143] Step S12, determining the corresponding impedance according to the admittance of all the segments to be measured.

[0144] Specifically, take The reciprocal of each element in obtains the corresponding impedance between each node.

[0145] By adopting the technical solution of this embodiment, a method is proposed to realize accurate online measurement and reconstruction of distribution network line parameters by using the voltage and current measured on the low-voltage side of the transformer, and the first voltage matrix and the second voltage matrix are merged into a total voltage matrix; the total voltage matrix, the total current column vector, and the admittance column vector are merged into a total voltage matrix equation; it is used to determine the admittance of all sections to be measured, and then determine the corresponding impedance. Such a voltage matrix equation has strong convergence due to the addition of the second matrix equation, and the line impedance inverted by online real-time calculation is more accurate, which can provide accurate line parameters and topology information for real-time setting of power grid protection constants and real-time power flow calculation, support power grid planning, dispatching, operation control, source-grid-load-storage interaction and other applications to help build new power systems.

[0146] In a specific embodiment, when the distribution network is reconstructed using matrix equations, the voltage and current vectors on the low-voltage side of the distribution transformer need to be converted to the high-voltage side line, and then the voltage vectors of each measurement node of the section to be measured are obtained, for example ..., and obtain the current vector of each measurement node of the section to be measured, for example ..., which is subsequently substituted into the voltage matrix equation to calculate the admittance. Usually, the current vector of each measuring node of the section to be measured is obtained through current vector analysis, and the voltage vector of each measuring node of the section to be measured is obtained through voltage vector analysis.

[0147] Furthermore, the connection group of the power transformer in the distribution network is usually Dyn11. The following is based on the Dyn11 distribution transformer research and analysis to convert the low-voltage side voltage and current vectors into high-voltage side vectors. That is, in a specific embodiment, the current vector analysis and voltage vector analysis of the following examples can be referred to to obtain the current vector of each measurement node in the section to be measured and the voltage vector of each measurement node in the section to be measured.

[0148] In a specific embodiment, the current vector is analyzed as follows:

[0149] First, the 0.4kV low-voltage side current is calculated using the formula The symmetrical component method decomposes the current into positive sequence, negative sequence and zero sequence current.

[0150] in, are the positive, negative and zero sequence components of the A phase current on the low voltage side of the distribution transformer, The three-phase currents of A, B, and C on the low-voltage side of the distribution transformer, a=e j120° 、a 2 =e j240° .

[0151] Since the high-voltage side is a angular connection, the line current on the high-voltage side does not contain zero-sequence current. Ignoring the influence of the excitation impedance shunt of the distribution transformer (if the no-load current and no-load loss are known, they can be calculated), the current on the low-voltage side of the distribution transformer is converted into the positive-sequence current on the high-voltage side. and negative sequence current They are:

[0152] Further, the positive sequence current on the high voltage side of the distribution transformer and negative sequence current Synthesize the A, B, and C phase line currents on the high voltage side for:

[0153] In summary, the high-voltage side line current vector is completed. Conversion.

[0154] Further, as Figure 5 The distribution transformer vector analysis simulation model schematic diagram is shown in the figure to perform simulation calculations to verify the high-voltage side line current vector Is the conversion correct?

[0155] The distribution transformer voltage ratio is 10kV / 0.4kV, the connection group is Dyn1, and an unbalanced load is set on the 0.4kV side of the distribution transformer. The distribution transformer parameters here mainly set the rated voltage, rated capacity, and leakage reactance on both sides, ignoring copper loss and iron loss. Figure 5The distribution transformer parameters of the distribution transformer vector analysis simulation model shown are mainly set on both sides of the rated voltage, rated capacity, leakage reactance, and copper loss and iron loss are ignored.

[0156] Assuming the rated voltage ratio of the distribution transformer is 25, the distribution transformer capacity is 50kVA and the leakage reactance is 0.1pu, the leakage reactance converted to the low voltage side is: X T2 =0.4×0.4÷50×1000×0.1=0.32jΩ. The current vector calculated by the theoretical formula and the current vector calculated by PSCAD simulation are as follows:

[0157] (1) Calculation of positive sequence current on the high voltage side

[0158] 1) Measure the positive sequence current on the low voltage side 369.8∠-130.2°A

[0159] 2) Calculate the positive sequence current on the high voltage side

[0160] 3) The positive sequence current on the high-voltage side calculated by PSCAD simulation is 14.8∠-160.25°A

[0161] (2) Calculation of negative sequence current on high voltage side

[0162] 1) Measure the negative sequence current on the low voltage side 135.6∠106.9°A

[0163] 2) Calculate the negative sequence current on the high voltage side

[0164] 3) The negative sequence voltage on the high-voltage side calculated by PSCAD simulation is 5.4∠136.9°

[0165] (3) Calculate the current of each phase on the high voltage side

[0166]

[0167]

[0168]

[0169] (4) Phase currents on the high-voltage side calculated by PSCAD simulation

[0170]

[0171]

[0172]

[0173] The maximum amplitude error between the calculated high-voltage side current and the high-voltage side current amplitude calculated by PSCAD simulation is 0.02A, and the maximum phase error is 0.06°, as shown in Table 1. It can be seen that the conclusion of the current vector analysis is correct. The current vector error obtained by this calculation is very small and has high accuracy. It can be used to substitute into the voltage matrix equation of this application to calculate the admittance, and then calculate the corresponding impedance.

[0174] Table 1:

[0175]

[0176] In a specific embodiment, the voltage vector is analyzed as follows:

[0177] The voltage on the 0.4kV low-voltage side of the distribution transformer is calculated using the formula The symmetrical component method decomposes into positive-sequence, negative-sequence and zero-sequence voltages.

[0178] Further, the positive-sequence power supply voltage and negative-sequence power supply voltage on the 0.4kV low-voltage side of the distribution transformer are calculated based on the positive-sequence circuit and negative-sequence circuit on the 0.4kV low-voltage side of the distribution transformer. The positive-sequence circuit of the Dyn11 distribution transformer is as follows: Figure 6 The positive sequence circuit diagram of the distribution transformer is shown in the figure.

[0179] It is the positive sequence power supply voltage on the 0.4kV low voltage side of the distribution transformer. The positive sequence voltage is calculated by the symmetrical component method of the voltage measured at the 0.4kV low voltage side terminal. is the positive sequence current calculated by the symmetrical component method of the current measured at the 0.4kV low voltage side terminal, X T2+ It is the positive sequence impedance converted from the high voltage side of the distribution transformer to the low voltage side (only the leakage reactance is considered, and the excitation reactance and winding resistance are ignored).

[0180] according to Figure 6 The positive sequence power supply voltage on the 0.4kV low voltage side of the distribution transformer is obtained

[0181] further The positive sequence voltage converted to the 10kV high voltage side of the distribution transformer is:

[0182] in, is the positive sequence voltage on the high voltage side of the distribution transformer, and k is the distribution transformer ratio.

[0183] Furthermore, the negative sequence loop impedance of the Dyn11 distribution transformer is equal to the positive sequence loop impedance. The negative sequence loop of the distribution transformer is shown as follows: Figure 7 The negative sequence circuit diagram of the distribution transformer shown

[0184] The negative sequence power supply voltage on the 0.4kV low voltage side of the distribution transformer. The negative sequence voltage is calculated by the symmetrical component method of the voltage measured at the 0.4kV low voltage side terminal. is the negative sequence current calculated by the symmetrical component method of the current measured at the 0.4kV low voltage side terminal, X T2- It is the negative sequence impedance converted from the high voltage side of the distribution transformer to the low voltage side.

[0185] according to Figure 7 The negative sequence power supply voltage on the 0.4kV low voltage side of the distribution transformer is

[0186] further The positive sequence voltage converted to the high voltage side is

[0187] in, is the positive sequence voltage on the high voltage side of the distribution transformer, and k is the distribution transformer ratio.

[0188] Furthermore, the zero-sequence impedance on the high-voltage side of the distribution transformer Dyn11 is very small, and the zero-sequence voltage is approximately 0, so the positive-sequence voltage on the high-voltage side of the distribution transformer is and negative sequence voltage Synthesized high-voltage side A, B, C phase voltage for:

[0189]

[0190] In summary, the high-voltage side phase voltage is completed. Conversion.

[0191] Further, as Figure 5 The distribution transformer vector analysis simulation model schematic diagram is shown in the figure to perform simulation calculations to verify the high-voltage side phase voltage vector Is the conversion correct?

[0192] The distribution transformer voltage ratio is 10kV / 0.4kV, the connection group is Dyn1, and an unbalanced load is set on the 0.4kV side of the distribution transformer. The distribution transformer parameters here mainly set the rated voltage, rated capacity, and leakage reactance on both sides, ignoring copper loss and iron loss. Figure 5 The distribution transformer parameters of the distribution transformer vector analysis simulation model shown are mainly set on both sides of the rated voltage, rated capacity, leakage reactance, and copper loss and iron loss are ignored.

[0193] (1) Calculation of positive sequence voltage on high voltage side

[0194] 1) PSCAD simulation calculation of low voltage side positive sequence voltage 126.12∠-78.6°V

[0195] 2) PSCAD simulation calculation of low voltage side positive sequence current 369.8∠-130.2°A

[0196] 3) Calculate the positive sequence power supply voltage on the low voltage side

[0197] 4) Calculate the positive sequence voltage on the high voltage side

[0198] 5) The positive sequence voltage on the high-voltage side calculated by PSCAD simulation is 5773.12∠-90.04°

[0199] (2) Calculation of negative sequence voltage on high voltage side

[0200] 1) PSCAD simulation calculation of low voltage side negative sequence voltage 43.4∠-16.9°V

[0201] 2) PSCAD simulation calculation of low voltage side negative sequence current 135.6∠106.9°A

[0202] 3) Calculate the open circuit negative sequence voltage on the low voltage side

[0203] 4) Calculate the negative sequence voltage on the high voltage side

[0204] 5) The negative sequence voltage on the high voltage side calculated by PSCAD simulation is 0.05∠-54.5°

[0205] (3) Calculate the voltage of each phase on the high voltage side

[0206]

[0207]

[0208]

[0209] (4) Phase voltages on the high-voltage side calculated by PSCAD simulation

[0210]

[0211]

[0212]

[0213] It can be seen that the maximum error between the calculated high-voltage side voltage and the high-voltage side voltage amplitude calculated by PSCAD simulation is 3V, the error is 0.05%, and the maximum phase error is 0.01°, as shown in Table 2. It can be seen that the conclusion of the voltage vector analysis is correct. The voltage vector error obtained by this calculation is very small and has high accuracy. It can be used to substitute into the voltage matrix equation of this application to calculate the admittance, and then calculate the corresponding impedance.

[0214] Table 2

[0215]

[0216]

[0217] In the embodiment of the present application, a line impedance online real-time accurate inversion calculation device is provided. Figure 8 , Figure 8 1 is a structural diagram of an on-line real-time accurate inversion calculation device for line impedance in an embodiment, wherein the on-line real-time accurate inversion calculation device for line impedance comprises a selection module 201 , a voltage module 202 , a current module 203 , an admittance module 204 , and a calculation module 205 .

[0218] The selection module 201 is configured to select a number of measurement nodes in the distribution network according to the section to be measured;

[0219] The selection module 201 is further configured to determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0220] The voltage module 202 is configured to form a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes of the main line;

[0221] The voltage module 202 is further configured to form a branch voltage matrix according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between every two adjacent measurement nodes;

[0222] The voltage module 202 is further configured to combine the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0223] The current module 203 is configured to form a current column vector according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0224] The admittance module 204 is configured to construct an admittance column vector according to the admittance of each section to be measured;

[0225] A calculation module 205 is configured to combine the first voltage matrix, the current column vector, and the admittance column vector to form a first voltage matrix equation for inverse calculation of the first admittance;

[0226] The calculation module 205 is further configured to form a second voltage matrix equation according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0227] The calculation module 205 is further configured to merge the second voltage matrix equation into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0228] The calculation module 205 is further configured to determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0229] The calculation module 205 is further configured to determine the corresponding impedance according to the admittance of all the segments to be measured.

[0230] In some implementations, the selection module 201 is further configured to determine all monitoring nodes included in the segment to be tested;

[0231] Sorting all the monitoring nodes according to the direction of the distribution network line;

[0232] The head-end nodes or the terminal nodes among all the monitoring nodes after sorting are removed, and the remaining monitoring nodes are used as measurement nodes.

[0233] In some embodiments, the voltage module 202 is further configured to determine the main line voltage matrix The elements of are: Where i=1 to n, n is the number of main line nodes, and j is 1 to n.

[0234] In some embodiments, the voltage module 202 is further configured to determine the branch voltage matrix The elements of are: Among them, if the i node has a branch, then k=i, k is the total number of branches, i=1 to p, p is the number of branch line nodes, and j is 1 to p.

[0235] In some implementations, the voltage module 202 is further configured to combine the main line voltage matrix with the diagonal line of the branch line voltage matrix of each branch line to form the first voltage matrix.

[0236] In some implementations, the current module 203 is further configured to determine each element of the current column vector as:

[0237] In some implementations, the admittance module 204 is further configured to determine each element of the admittance column vector as: i1 =Y(i-1.i).

[0238] In some implementations, the calculation module 205 is further configured to determine the first voltage matrix equation as: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector.

[0239] In some embodiments, the calculation module 205 is further configured to merge the second voltage matrix equation into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured, including:

[0240] The voltage difference between the node at the main line outlet of the distribution network and the measurement node closest to it is expanded into a second voltage matrix in the second voltage matrix equation of 1*j, U11 is U0-U1, when j>1, U1j=0, and it is added as the first row of the first voltage matrix in the first voltage matrix equation to form the total voltage matrix in the total voltage matrix equation;

[0241] The outflow current at the node of the main line outlet in the second voltage matrix equation is Added as the first row of the current column vector in the first voltage matrix equation to form the total current column vector in the total voltage matrix equation;

[0242] The total voltage matrix, the admittance column vector, and the total current column vector constitute the total voltage matrix equation used for inverse calculation of the admittance of the section to be measured.

[0243] In some implementations, the calculation module 205 is further configured to determine the total voltage matrix equation as: in, is the main line voltage matrix, Y 主 is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, Y 支k is the branch admittance vector, is the branch current vector, The pressure difference between the node at the main line outlet and the closest measurement node, It is the outflow current of the node where the main line exits.

[0244] For other details about how each module in the device for online real-time accurate inversion calculation of line impedance implements the above technical solution, please refer to the description of the online real-time accurate inversion calculation of line impedance provided above, which will not be repeated here.

[0245] In an embodiment of the present application, a computer device is provided. Fig. 9 , Fig. 93 is a schematic diagram of the structure of a computer device in an embodiment. The device includes a memory 301 and a processor 302. The memory 301 stores a computer program. When the computer program is executed by the processor 302, the processor 302 performs the following steps:

[0246] Selecting several measuring nodes in the distribution network according to the section to be measured;

[0247] Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0248] Forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0249] A branch line voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes;

[0250] Combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0251] A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0252] Construct an admittance column vector according to the admittance of each section to be measured;

[0253] The first voltage matrix, the current column vector, and the admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance;

[0254] A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0255] The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0256] Determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0257] The corresponding impedance is determined according to the admittance of all the sections to be measured.

[0258] Among them, the processor 302 can also be called a CPU (Central Processing Unit), and the processor 302 may be an integrated circuit chip with signal processing capabilities; the processor 302 can also be a general-purpose processor, DSP (Digital Signal Process), ASIC (Application Specific Integrated Circuit), FPGA (Field Programmable Gate Array) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, among which the general-purpose processor can be a microprocessor or the processor 302 can also be any conventional processor, etc.

[0259] In an embodiment of the present application, a computer readable storage medium is provided. Fig.10 , Fig.10 The structure diagram of a computer-readable storage medium in an embodiment is a schematic diagram, on which a readable computer program 401 is stored; wherein the computer program 401 may be stored in the above storage medium in the form of a software product, and includes a number of instructions for causing a computer device (which may be a personal computer, a server machine, or a network device, etc.) or a processor to perform the following steps:

[0260] Selecting several measuring nodes in the distribution network according to the section to be measured;

[0261] Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line;

[0262] Forming a main line voltage matrix according to the voltage difference between every two adjacent measurement nodes among the measurement nodes of the main line;

[0263] A branch line voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes;

[0264] Combining the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix;

[0265] A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network;

[0266] Construct an admittance column vector according to the admittance of each section to be measured;

[0267] The first voltage matrix, the current column vector, and the admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance;

[0268] A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node;

[0269] The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured;

[0270] Determine the admittance of all the segments to be measured according to the total voltage matrix equation;

[0271] The corresponding impedance is determined according to the admittance of all the sections to be measured.

[0272] The aforementioned storage media include: U disk, mobile hard disk, magnetic disk or CD, ROM (Read-Only Memory), RAM (Random Access Memory) and other media that can store program code, or terminal devices such as computers, service machines, mobile phones, and tablets.

[0273] Those skilled in the art can understand that all or part of the processes in the above-mentioned embodiment methods can be completed by instructing the relevant hardware through a computer program, and the program can be stored in a non-volatile computer-readable storage medium. When the program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, storage, database or other media used in the embodiments provided in this application can include non-volatile and / or volatile memory. Non-volatile memory may include read-only memory (ROM), programmable ROM (PROM), electrically programmable ROM (EPROM), electrically erasable programmable ROM (EEPROM) or flash memory. Volatile memory may include random access memory (RAM) or external cache memory. As an illustration and not limitation, RAM is available in many forms, such as static RAM (SRAM), dynamic RAM (DRAM), synchronous DRAM (SDRAM), double data rate SDRAM (DDRSDRAM), enhanced SDRAM (ESDRAM), synchronous link (Synchlink) DRAM (SLDRAM), memory bus (Rambus) direct RAM (RDRAM), direct memory bus dynamic RAM (DRDRAM), and memory bus dynamic RAM (RDRAM).

[0274] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0275] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for online real-time accurate inversion calculation of line impedance, characterized in that: The method comprises: Selecting several measuring nodes in the distribution network according to the section to be measured; Determine a number of measurement nodes located on the main line and measurement nodes located on each branch line; A main line voltage matrix is ​​formed according to the voltage difference between every two adjacent measurement nodes of the main line. The elements of are: ; where i = 1 to n, n is the number of main line nodes, j is 1 to n, is the voltage of node i-1, is the voltage of node i, is the voltage of node i+1; A branch voltage matrix is ​​formed according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes. The elements of are: ; Wherein, if the i node has a branch, then k=i, k is the total number of branches, i=1 to p, p is the number of branch line nodes, and j is 1 to p; The main line voltage matrix and the branch line voltage matrix are combined to form a first voltage matrix, including placing the first element of the first row of the branch line voltage matrix of the first branch line in the last column of the row below the last element in the main line voltage matrix, and placing the first element of the first row of the N-th branch line voltage matrix of the remaining branches in the last column of the row below the last element in the N-1-th branch line voltage matrix, and finally forming the first voltage matrix; A current column vector is formed according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network. The current column vector includes and , the main line current column vector The elements of are: , where i = 1 to n, n is the number of nodes in the main line; the branch current column vector The elements of are: , where k is the branch line number, i = 1 to p, and p is the number of branch line nodes; The admittance column vector is formed according to the admittance of each section to be measured. The admittance column vector includes Y 主 and Y 支k , admittance column vector The elements of are: , where i = 1 to n, n is the number of main line nodes; the admittance column vector The elements of are: , where k is the branch line number, i = 1 to p, and p is the number of branch line nodes; The first voltage matrix, current column vector, and admittance column vector are combined to form a first voltage matrix equation for inverse calculation of the first admittance. The first voltage matrix equation is: ,in, For the main line voltage matrix, is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, is the branch admittance vector, is the branch current vector; A second voltage matrix equation is formed according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node; The second voltage matrix equation is merged into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured, including: the voltage difference between the node at the main line outlet in the distribution network and the measurement node closest to it is expanded to the second voltage matrix in the second voltage matrix equation of 1*j, U11 is U0-U1, when j>1, U1j=0, U11 is the element of the first row and first column in the second voltage matrix, U0-U1 is the voltage difference between the node at the main line outlet in the distribution network and the measurement node closest to it, and U1j is the second voltage matrix The element of the first row and the jth column in the first voltage matrix equation, j is 1 to n; add it as the first row of the first voltage matrix in the first voltage matrix equation to form the total voltage matrix in the total voltage matrix equation; add the outflow current I0 of the node at the main line outlet in the second voltage matrix equation to the first row of the current column vector in the first voltage matrix equation to form the total current column vector in the total voltage matrix equation; the total voltage matrix, the admittance column vector, and the total current column vector constitute the total voltage matrix equation for inverse calculation of the admittance of the section to be measured, and the total voltage matrix equation is: ,in, is the main line voltage matrix, is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, is the branch admittance vector, is the branch current vector, The pressure difference between the node at the main line outlet and the closest measurement node, is the outflow current of the node where the main line is outgoing; Determine the admittance of all the segments to be measured according to the total voltage matrix equation; The corresponding impedance is determined according to the admittance of all the sections to be measured.

2. The method for online real-time accurate inversion calculation of line impedance according to claim 1 is characterized in that: The step of selecting a plurality of measurement nodes in the distribution network according to the section to be measured specifically includes: Determine all monitoring nodes included in the segment to be tested; Sort all monitoring nodes according to the direction of the distribution network line; The head-end nodes or the terminal nodes among all the monitoring nodes after sorting are removed, and the remaining monitoring nodes are used as measurement nodes.

3. A line impedance online real-time accurate inversion calculation device, characterized in that: The device comprises: A selection module is used to select a number of measurement nodes in the distribution network according to the section to be measured; The selection module is further used to determine the measurement nodes of the main line and the measurement nodes of each branch line; A voltage module is used to form a main line voltage matrix according to the voltage difference between each two adjacent measurement nodes of the main line. The elements of are: ; where i = 1 to n, n is the number of main line nodes, j is 1 to n, is the voltage of node i-1, is the voltage of node i, is the voltage of node i+1; The voltage module is further used to form a branch voltage matrix according to the voltage difference between the branch head node and the closest measurement node in the measurement nodes of each branch line, and the voltage difference between each two adjacent measurement nodes. The elements of are: ; Wherein, if the i node has a branch, then k=i, k is the total number of branches, i=1 to p, p is the number of branch line nodes, and j is 1 to p; The voltage module is further used to combine the main line voltage matrix and the branch line voltage matrix to form a first voltage matrix, including placing the first element of the first row of the branch line voltage matrix of the first branch line in the last column of the row below the last element in the main line voltage matrix, placing the first element of the first row of the N-th branch line voltage matrix of the remaining branches in the last column of the row below the last element in the N-1-th branch line voltage matrix, and finally forming the first voltage matrix; A current module is used to form a current column vector according to the current flowing out of the measurement node of each main line in the distribution network and the current flowing out of the measurement node of each branch line along the line direction of the distribution network. The current column vector includes and , the main line current column vector The elements of are: , where i = 1 to n, n is the number of nodes in the main line; the branch current column vector The elements of are: , where k is the branch line number, i = 1 to p, and p is the number of branch line nodes; The admittance module is used to form an admittance column vector according to the admittance of each section to be measured. The admittance column vector includes Y 主 and Y 支k , admittance column vector The elements of are: , where i = 1 to n, n is the number of main line nodes; the admittance column vector The elements of are: , where k is the branch line number, i = 1 to p, and p is the number of branch line nodes; A calculation module is used to combine the first voltage matrix, the current column vector, and the admittance column vector to form a first voltage matrix equation for inverse calculation of the first admittance, wherein the first voltage matrix equation is: ,in, For the main line voltage matrix, is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, is the branch admittance vector, is the branch current vector; The calculation module is further used to form a second voltage matrix equation according to the voltage difference between the node at the main line outlet and the closest measurement node in the distribution network, the outflow current of the node at the main line outlet, and the admittance between the node at the main line outlet and the closest measurement node; The calculation module is also used to merge the second voltage matrix equation into the first voltage matrix equation to form a total voltage matrix equation for inverse calculation of the admittance of the section to be measured, including: expanding the voltage difference between the node at the main line outlet in the distribution network and the measurement node closest to it into a second voltage matrix in the second voltage matrix equation of 1*j, U11 is U0-U1, when j>1, U1j=0, U11 is the element of the first row and first column in the second voltage matrix, U0-U1 is the voltage difference between the node at the main line outlet in the distribution network and the measurement node closest to it, and U1j is the first The elements of the first row and the jth column in the second voltage matrix, where j is 1 to n, are added as the first row of the first voltage matrix in the first voltage matrix equation to form the total voltage matrix in the total voltage matrix equation; the outflow current I0 of the node at the main line outlet in the second voltage matrix equation is added as the first row of the current column vector in the first voltage matrix equation to form the total current column vector in the total voltage matrix equation; the total voltage matrix, the admittance column vector, and the total current column vector form the total voltage matrix equation for inverse calculation of the admittance of the section to be measured, and the total voltage matrix equation is: ,in, is the main line voltage matrix, is the principal line admittance vector, is the main line current vector, is the branch voltage matrix, is the branch admittance vector, is the branch current vector, The pressure difference between the node at the main line outlet and the closest measurement node, is the outflow current of the node where the main line is outgoing; The calculation module is further used to determine the admittance of all the segments to be measured according to the total voltage matrix equation; The calculation module is further used to determine the corresponding impedance according to the admittance of all the segments to be measured.

4. A computer device comprising a memory and a processor, wherein the memory stores a computer program, and when the computer program is executed by the processor, the processor executes the steps of the method according to claim 1 or 2.

5. A computer-readable storage medium storing a computer program, wherein when the computer program is executed by a processor, the processor executes the steps of the method according to claim 1 or 2.

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