CN114707283B - Grounding grid corrosion diagnosis method based on Lasso theory - Google Patents

Grounding grid corrosion diagnosis method based on Lasso theory Download PDF

Info

Publication number
CN114707283B
CN114707283B CN202210350908.XA CN202210350908A CN114707283B CN 114707283 B CN114707283 B CN 114707283B CN 202210350908 A CN202210350908 A CN 202210350908A CN 114707283 B CN114707283 B CN 114707283B
Authority
CN
China
Prior art keywords
grounding grid
corrosion
branch
node
coping
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202210350908.XA
Other languages
Chinese (zh)
Other versions
CN114707283A (en
Inventor
陈艳华
王宏兴
李善飞
李加加
杨华
刘啸辰
钟文帆
程宏波
徐茂华
武素芳
刘建新
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Third Engineering Co Ltd of China Railway Electrification Engineering Group Co Ltd
CREC EEB Operation Maintenance Co Ltd
Original Assignee
Third Engineering Co Ltd of China Railway Electrification Engineering Group Co Ltd
CREC EEB Operation Maintenance Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Third Engineering Co Ltd of China Railway Electrification Engineering Group Co Ltd, CREC EEB Operation Maintenance Co Ltd filed Critical Third Engineering Co Ltd of China Railway Electrification Engineering Group Co Ltd
Priority to CN202210350908.XA priority Critical patent/CN114707283B/en
Publication of CN114707283A publication Critical patent/CN114707283A/en
Application granted granted Critical
Publication of CN114707283B publication Critical patent/CN114707283B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/10—Geometric CAD
    • G06F30/18—Network design, e.g. design based on topological or interconnect aspects of utility systems, piping, heating ventilation air conditioning [HVAC] or cabling
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/041—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance of a solid body
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
    • G01N27/02—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance
    • G01N27/04—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating impedance by investigating resistance
    • G01N27/20—Investigating the presence of flaws
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/11—Complex mathematical operations for solving equations, e.g. nonlinear equations, general mathematical optimization problems
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F17/00—Digital computing or data processing equipment or methods, specially adapted for specific functions
    • G06F17/10—Complex mathematical operations
    • G06F17/16—Matrix or vector computation, e.g. matrix-matrix or matrix-vector multiplication, matrix factorization
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F18/00—Pattern recognition
    • G06F18/20—Analysing
    • G06F18/21—Design or setup of recognition systems or techniques; Extraction of features in feature space; Blind source separation
    • G06F18/213—Feature extraction, e.g. by transforming the feature space; Summarisation; Mappings, e.g. subspace methods
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F18/00—Pattern recognition
    • G06F18/20—Analysing
    • G06F18/21—Design or setup of recognition systems or techniques; Extraction of features in feature space; Blind source separation
    • G06F18/214—Generating training patterns; Bootstrap methods, e.g. bagging or boosting
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F30/00—Computer-aided design [CAD]
    • G06F30/20—Design optimisation, verification or simulation
    • G06F30/27—Design optimisation, verification or simulation using machine learning, e.g. artificial intelligence, neural networks, support vector machines [SVM] or training a model
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y04—INFORMATION OR COMMUNICATION TECHNOLOGIES HAVING AN IMPACT ON OTHER TECHNOLOGY AREAS
    • Y04S—SYSTEMS INTEGRATING TECHNOLOGIES RELATED TO POWER NETWORK OPERATION, COMMUNICATION OR INFORMATION TECHNOLOGIES FOR IMPROVING THE ELECTRICAL POWER GENERATION, TRANSMISSION, DISTRIBUTION, MANAGEMENT OR USAGE, i.e. SMART GRIDS
    • Y04S10/00—Systems supporting electrical power generation, transmission or distribution
    • Y04S10/50—Systems or methods supporting the power network operation or management, involving a certain degree of interaction with the load-side end user applications

Landscapes

  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Theoretical Computer Science (AREA)
  • Data Mining & Analysis (AREA)
  • Mathematical Physics (AREA)
  • General Engineering & Computer Science (AREA)
  • Mathematical Analysis (AREA)
  • Pure & Applied Mathematics (AREA)
  • Mathematical Optimization (AREA)
  • Evolutionary Computation (AREA)
  • Computational Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Artificial Intelligence (AREA)
  • Software Systems (AREA)
  • Geometry (AREA)
  • Computer Hardware Design (AREA)
  • Electrochemistry (AREA)
  • Bioinformatics & Cheminformatics (AREA)
  • Pathology (AREA)
  • Bioinformatics & Computational Biology (AREA)
  • Algebra (AREA)
  • Databases & Information Systems (AREA)
  • Evolutionary Biology (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Immunology (AREA)
  • Health & Medical Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • Medical Informatics (AREA)
  • Operations Research (AREA)
  • Computing Systems (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Management, Administration, Business Operations System, And Electronic Commerce (AREA)

Abstract

The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, which comprises the following steps: step 1: establishing a structural relation matrix of a transformer substation grounding grid, and simultaneously acquiring basic parameters of the transformer substation grounding grid; step 2: detecting a transformer substation grounding grid to obtain detection parameters; and step 3: establishing a corrosion diagnosis equation set of the grounding grid of the transformer substation based on the structural relationship matrix, the basic parameters and the detection parameters; and 4, step 4: iteratively solving the corrosion diagnosis equation set of the grounding grid of the transformer substation by utilizing the Lasso theory to obtain a solution result; and 5: and graphically displaying the corrosion degree of the grounding grid of the transformer substation based on the solving result. According to the grounding grid corrosion diagnosis method based on the Lasso theory, the Lasso theory is utilized to carry out sparse processing on branch resistance variation, and then the fault diagnosis equation set is solved, so that the problems that the indeterminate equation solution is easy to cause non-convergence and pseudo fault when an electric network method is adopted in transformer substation grounding grid corrosion diagnosis are solved.

Description

Grounding grid corrosion diagnosis method based on Lasso theory
Technical Field
The invention relates to the technical field of substation grounding grid fault diagnosis, in particular to a grounding grid corrosion diagnosis method based on the Lasso theory.
Background
The transformer substation grounding grid has the functions of voltage sharing and current leakage, and plays an important role in ensuring the safe and stable operation of a power system and protecting the personal safety of transformer substation workers and the operation safety of electrical equipment. The transformer substation grounding grid is mostly made of common steel or galvanized flat steel, and is easily affected by soil corrosion and electrochemical corrosion to cause corrosion thinning, even breakage and falling of a grounding body. The corrosion of the grounding grid can reduce the grounding performance of the grounding grid, raise the grounding potential of the grounding grid, endanger the equipment and personal safety and bring huge potential safety hazards to the operation of a transformer substation.
At present, three main methods are available for diagnosing corrosion of a grounding grid: electromagnetic, electrochemical and electrical network methods. An alternating current is injected into an outgoing line of a grounding grid by an electromagnetic method, and the corrosion of the grounding grid is diagnosed and positioned by detecting the distribution condition of magnetic induction intensity on the ground, so that the electromagnetic method has the problem of electromagnetic interference, and particularly, a strong electromagnetic environment of a transformer substation can have great influence on a measurement result; the electrochemical method represents the corrosion condition of the grounding grid by utilizing electrochemical characteristics, the grounding grid can be oxidized to become an anode under the action of electrochemical corrosion, the electrochemical sensor is used for measuring polarization resistance of different positions of the grounding grid to diagnose the corrosion degree of the grounding grid, the electrochemical method needs to excavate a soil embedded sensor, and surrounding noise can affect detection precision; the electric network method utilizes an electric network theory and the Teller theorem to establish a fault diagnosis equation set, obtains the variable quantity of the resistance value of each branch of the grounding network according to the change condition of the port resistance, obtains the branch resistance of each branch of the grounding network by solving the equation set of the impedance change of the port network, and obtains the corrosion condition of each branch of the grounding network according to the resistance value of each branch resistance. The method is simple to operate and convenient to implement, but because the number of outgoing lines of the grounding network is less than the number of branches, the number of voltage and current equations of a port measured by an electric network method is less than the number of branches to be solved, so that an equation established by the electric network method is an underdetermined equation, at present, the equation is generally solved by an optimization method, such as documents [ Xu Lei, li Lin ], a transformer substation grounding network corrosion and breakpoint diagnosis method [ J ] based on an electric network theory, and 2012,27 (10): 270-276] are solved by a least square method, and the problems of overfitting, large error of diagnosis results, false faults and the like can be caused when the accessible nodes are too few (the number of the branches is too few).
Disclosure of Invention
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, which is characterized in that the Lasso theory is utilized to carry out sparse processing on branch resistance variation and then solve a fault diagnosis equation set so as to solve the problems that the existing underdetermined equation solution is easy to cause non-convergence and false faults when an electric network method is adopted in transformer substation grounding grid corrosion diagnosis.
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, which comprises the following steps:
step 1: establishing a structural relationship matrix of a transformer substation grounding grid, and simultaneously acquiring basic parameters of the transformer substation grounding grid;
and 2, step: detecting a transformer substation grounding grid to obtain detection parameters;
and 3, step 3: establishing a corrosion diagnosis equation set of the grounding grid of the transformer substation based on the structural relationship matrix, the basic parameters and the detection parameters;
and 4, step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by utilizing a Lasso theory to obtain a solution result;
and 5: and graphically displaying the corrosion degree of the grounding grid of the transformer substation based on the solving result.
Preferably, in step 1, establishing a structural relationship matrix of the substation grounding grid includes:
analyzing a topological structure of a design drawing of the transformer substation grounding grid, and establishing an incidence matrix A for describing a structural relationship of the transformer substation grounding grid;
the incidence matrix A describes the connection relation between nodes and branches of the transformer substation grounding network, the row of the matrix A represents a node element of the grounding network, and the column of the matrix A represents a branch element of the grounding network; taking a branch corresponding to the element as a reference direction from left to right and from top to bottom, wherein for each element of A, when the branch corresponding to the element leaves a node corresponding to the element according to the reference direction, the element takes +1; when the branch corresponding to the element enters the node corresponding to the element according to the reference direction, taking-1 as the element; when the branch corresponding to the element is not associated with the node corresponding to the element, the element takes 0.
Preferably, in the step 1, obtaining the basic parameters of the substation grounding grid includes:
calculating the nominal resistance value R of the branch according to the length of the branch of the transformer substation grounding grid and the grounding material adopted by the branch i ＝ρl i /s i Wherein i =1,2,3Is the total number of grounding grid branches, rho is the resistivity of the grounding grid branch metal, l i Is the length of the branch of the counterpoise, s i The sectional area of the branch metal of the grounding grid is obtained, and the branch nominal resistance vector R of the grounding grid is obtained according to the sectional area k ＝(R 1 ,R 2 ,...R i ,...,R b )；
By branch nominal resistance vector R k Get ground net branch conductance matrix
Figure GDA0003806272220000031
Further obtaining a grounding grid node conductance matrix G n ＝AG b A T And the subscript n represents the total number of the nodes of the grounding grid.
Preferably, the step 2: detecting the transformer substation grounding grid to obtain detection parameters, comprising:
taking a node with a leading-out wire on a transformer substation ground grid as a reachable node, selecting any node in the transformer substation ground grid as a reference node, and injecting direct current I between the reference node and the reachable node 1 0 Measuring a port voltage value U 'between the reachable node 1 and the reference node' (1) ；
Selecting the next available node and injecting a DC current I between the next available node and the reference node 0 Measuring a port voltage value U 'between the reachable node and a reference node' (2) ；
And repeating the operation on the rest reachable nodes in sequence, and recording the corresponding port voltage value U' (m) M is the number of the accessible nodes to obtain the injected DC current I 0 Port voltage vector U ' = (U ' of the case ' (1) ,U’ (2) ,…,U’ (m) )。
Preferably, the step 3: establishing a transformer substation grounding grid corrosion diagnosis equation set based on the structural relationship matrix, the basic parameters and the detection parameters, wherein the equation set comprises the following steps:
(31) According to the network topology of the transformer substation grounding network and the grounding network node conductance matrix G calculated in the step 1, the reference node selected in the step 2 is used n ＝AG b A T Calculate the respective reachable nodes in step 2Injecting a direct current I 0 Under the condition, the voltage theoretical value of each node of the transformer substation grounding grid is as follows:
Figure GDA0003806272220000041
Figure GDA0003806272220000042
in which I n Is the injection node n current vector, I n ＝(0 (1) ,0 (2) ,...,I 0(i) ,...,-I 0(j) ,...,0 (n) )；
(32) Calculating the theoretical value of the current of the grounding grid branch circuit, I k(1) ＝G b A T U n(1) ，I k(2) ＝G b A T U n(2) ，...，I k(m) ＝G b A T U n(m) And accordingly obtaining the theoretical value of the current vector of the branch circuit of the grounding grid as I k ＝(I k(1) ,I k(2) ,...,I k(m) )；
(33) According to the theoretical voltage value of each node of the grounding grid, calculating the direct current I injected into each accessible node 0 The theoretical value of the port voltage between each reachable node and the reference node is U = (U) (1) ,U (2) ,……U (m) )；
(34) Calculating theoretical values of the port resistances of the accessible nodes of the grounding grid according to ohm's law: r is ij(1) ＝U (1) /I 0 ，R ij(2) ＝U (2) /I 0 ，...，R ij(m) ＝U (m) /I 0 And obtaining the theoretical value vector R of the port resistance of the grounding grid according to the above ij ＝(R ij(1) ,R ij(2) ,...,R ij(m) )；
(35) Obtaining detection parameters of the grounding grid according to the step 2, and calculating actual values R 'of port resistances of the accessible nodes and the reference nodes of the grounding grid' ij(1) ＝U’ (1) /I 0 ，R’ ij(2) ＝U’ (2) /I 0 ，...，R’ ij(m) ＝U’ (m) /I 0 And obtaining the actual value vector R 'of the port resistance of the grounding grid according to the actual value vector R' ij ＝(R’ ij(1) ,R’ ij(2) ,...,R’ ij(m) )；
(36) Calculating the change quantity of the actual value and the theoretical value of the port resistance of the grounding grid: delta R ij ＝R’ ij -R ij ；
(37) Establishing a relation between the resistance variation of the grounding network branch and the resistance variation of the port through the Taylor's theorem:
Figure GDA0003806272220000043
wherein, Δ R ij Is the variation quantity of the actual value and the theoretical value of the port resistance of the grounding grid calculated in (36), delta R k Is the amount of resistance change of the branch of the grounding grid to be solved, I k Is the theoretical value of the current vector of the earth network branch, I ', calculated in (32)' k Is the actual value of each branch current after corrosion and the resistance variation quantity Delta R of the branch resistor k Related to, I 0 Is the value of the dc current injected between the reach node and the reference node.
Preferably, the step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by using a Lasso theory to obtain a solution result, wherein the solution result comprises the following steps:
(41) Setting the initial value of each branch current after corrosion to make
Figure GDA0003806272220000051
Then the branch resistance equation of the grounding grid in the step three) is changed into
Figure GDA0003806272220000052
(42) Randomization initialization
Figure GDA0003806272220000053
Supply of Δ R k Randomly taking an initial value
Figure GDA0003806272220000054
(43) From
Figure GDA0003806272220000055
Figure GDA0003806272220000056
Until now, in turn find
Figure GDA0003806272220000057
Figure GDA0003806272220000058
The solution of (a) is as follows:
Figure GDA0003806272220000059
wherein | | | purple hair 1 Is the regularization of L1 and,
Figure GDA00038062722200000510
λ∈[0,1]the penalty coefficient can be specified artificially;
at the solution of
Figure GDA00038062722200000511
When the utility model is used, the water is discharged,
Figure GDA00038062722200000512
are all constants;
sequentially find out
Figure GDA00038062722200000513
(44) Obtained by last calculation
Figure GDA00038062722200000514
Updating
Figure GDA00038062722200000515
And recalculate
Figure GDA00038062722200000516
Figure GDA00038062722200000517
Thereby obtainingBranch current value to next iteration
Figure GDA00038062722200000518
(45) Will be updated
Figure GDA00038062722200000519
Substitution equation
Figure GDA00038062722200000520
(46) Judgment of
Figure GDA00038062722200000521
(wherein epsilon is a set error constant) and if not, returning to (43) for circulation; if it is
Figure GDA00038062722200000522
Is established, then
Figure GDA00038062722200000523
The optimal solution of the equation of the resistance variation of the branch of the grounding grid and the resistance variation of the port is obtained;
(47) Calculating solution of actual value of branch resistance of grounding grid
Figure GDA00038062722200000524
Preferably, the step 5: based on the solution result, the corrosion degree of the transformer substation grounding grid is graphically displayed, and the method comprises the following steps:
according to the actual value of the branch resistance of the grounding grid obtained by the step 4, calculating the change multiple of the branch resistance
Figure GDA0003806272220000061
Wherein k =1,2., b, b represents the total number of grounding grid branches;
based on preset evaluation standard, according to branch resistance change multiple
Figure GDA0003806272220000062
To groundEvaluating the corrosion degree of each branch of the net to obtain an evaluation result;
graphically displaying the evaluation result, wherein the slightly corroded branch is represented by green, the moderately corroded branch is represented by yellow, and the severely corroded branch is represented by red;
and drawing an actual corrosion diagnosis result graph of each branch of the grounding grid according to the corrosion degree of each branch of the grounding grid, and outputting the graph.
Preferably, the method for diagnosing corrosion of a grounding grid based on the Lasso theory further includes:
step 6: and training a corrosion coping model, formulating a coping strategy according to the corrosion degree of the transformer substation grounding grid based on the corrosion coping model, and performing corresponding coping processing based on the coping strategy.
Preferably, in step 6, training the corrosion countermeasure model includes:
acquiring a plurality of first corrosion coping events, and acquiring a coping party corresponding to the first corrosion coping events;
acquiring a coping type corresponding to the counterparty, wherein the coping type comprises: internal coping and external coping;
when the corresponding type of the corresponding party is internal responding, acquiring an experience degree value corresponding to the corresponding party;
if the empirical degree value is less than or equal to a preset first threshold value, rejecting the corresponding first corrosion coping event;
when the corresponding type of the corresponding party is external corresponding, acquiring a credit degree value corresponding to the corresponding party;
if the credit degree value is less than or equal to a preset second threshold value, rejecting the corresponding first corrosion coping event;
when the first corrosion coping events needing to be removed are all removed, the remaining first corrosion coping events are removed to serve as second corrosion coping events;
carrying out rationality analysis on the second corrosion coping event to obtain a rational value;
if the reasonable value is greater than or equal to a preset third threshold value, taking the corresponding second corrosion coping event as a third corrosion coping event;
and performing model training according to the third corrosion coping event based on a preset model training algorithm to obtain a corrosion coping model.
Preferably, the rationality analysis is performed on the second corrosion countermeasure event to obtain a rational value, including:
acquiring a plurality of expert nodes, and simultaneously acquiring an evaluation value for reasonably evaluating the second corrosion coping event by the expert nodes;
acquiring expert weights corresponding to the expert nodes, giving the evaluation values corresponding to the expert weights, and acquiring target values;
and accumulating and calculating the target value to obtain a reasonable value.
Has the advantages that:
(1) The invention utilizes Lasso theory to compress characteristics, which not only can solve the over-fitting problem, but also can directly compress unimportant variables into 0 and delete the influence of invalid variables (uncorroded branches). Can achieve the purpose of extracting effective branch resistance variation quantity delta R in the parameter reduction process k (corroded branch). Not only can the more accurate fault diagnosis of the grounding grid be realized, but also the variable selection (dimension reduction) can be realized.
(2) The method solves the problem of blindness of corrosion diagnosis of the grounding grid, can accurately diagnose and position the fault without excavating soil in a large area, provides reference for replacing the grounding grid or not and selecting the excavating position, and further reduces the operation and maintenance cost of the on-site grounding grid.
(3) The invention enables the grounding grid corrosion diagnosis result to be visual and intuitive through graphical display and convenient application.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a flowchart of a grounding grid corrosion diagnosis method based on the Lasso theory according to an embodiment of the present invention;
fig. 2 is a schematic diagram of a network topology of a substation grounding grid in an embodiment of the present invention;
FIG. 3 is a schematic diagram of a corrosion diagnosis result of a grounding grid of a transformer substation according to an embodiment of the present invention;
fig. 4 is a flowchart of a grounding grid corrosion diagnosis method based on the Lasso theory according to another embodiment of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, which comprises the following steps of:
step 1: establishing a structural relation matrix of a transformer substation grounding grid, and simultaneously acquiring basic parameters of the transformer substation grounding grid;
step 2: detecting a transformer substation grounding grid to obtain detection parameters;
and step 3: establishing a corrosion diagnosis equation set of the grounding grid of the transformer substation based on the structural relationship matrix, the basic parameters and the detection parameters;
and 4, step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by utilizing a Lasso theory to obtain a solution result;
and 5: graphically displaying the corrosion degree of the grounding grid of the transformer substation based on the solving result;
in the step 1, establishing a structural relationship matrix of the transformer substation grounding grid includes:
analyzing a topological structure of a design drawing of the transformer substation grounding grid, and establishing an incidence matrix A for describing a structural relationship of the transformer substation grounding grid;
the incidence matrix A describes the connection relation between nodes and branches of the transformer substation grounding network, the row of the matrix A represents a node element of the grounding network, and the column of the matrix A represents a branch element of the grounding network; taking a branch corresponding to the element as a reference direction from left to right and from top to bottom, wherein for each element of A, when the branch corresponding to the element leaves a node corresponding to the element according to the reference direction, the element takes +1; when the branch corresponding to the element enters the node corresponding to the element according to the reference direction, taking-1 as the element; when the branch corresponding to the element is not associated with the node corresponding to the element, the element takes 0;
in the step 1, obtaining basic parameters of the substation grounding grid includes:
calculating the nominal resistance value R of the branch according to the length of the branch of the transformer substation grounding grid and the grounding material adopted by the branch i ＝ρl i /s i Wherein i =1,2,3., b, b is the total number of grounding grid branches, ρ is the resistivity of the grounding grid branch metal, and l i Is the length of the branch of the counterpoise, s i The sectional area of the branch metal of the grounding grid is obtained, and the branch nominal resistance vector R of the grounding grid is obtained according to the sectional area k ＝(R 1 ,R 2 ,...R i ,...,R b )；
By branch nominal resistance vector R k Get ground net branch conductance matrix
Figure GDA0003806272220000091
Further obtaining a grounding grid node conductance matrix G n ＝AG b A T Wherein, the subscript n represents the total number of the nodes of the grounding network;
the step 2: detecting the transformer substation grounding grid to obtain detection parameters, comprising:
taking a node provided with a lead-out wire on a transformer substation ground grid as a reachable node, selecting any node in the transformer substation ground grid as a reference node, and selecting the reference node and the reachable nodeInjecting a direct current I between 1 0 Measuring a port voltage value U 'between the reachable node 1 and the reference node' (1) ；
Selecting the next available node and injecting a DC current I between the next available node and the reference node 0 Measuring a port voltage value U 'between the reachable node and a reference node' (2) ；
And repeating the operation on the rest reachable nodes in sequence, and recording the corresponding port voltage value U' (m) M is the number of the accessible nodes to obtain the injected DC current I 0 Port voltage vector U ' = (U ' in the case ' (1) ,U’ (2) ,…,U’ (m) )；
The step 3: establishing a corrosion diagnosis equation set of the grounding grid of the transformer substation based on the structural relationship matrix, the basic parameters and the detection parameters, wherein the corrosion diagnosis equation set comprises the following steps:
(31) According to the network topology of the transformer substation grounding network and the grounding network node conductance matrix G calculated in the step 1, the reference node selected in the step 2 is used n ＝AG b A T Calculating the DC current I injected into each accessible node in step 2 0 Under the condition, the voltage theoretical value of each node of the transformer substation grounding grid is as follows:
Figure GDA0003806272220000101
Figure GDA0003806272220000102
wherein I n Is the injection node n current vector, I n ＝(0 (1) ,0 (2) ,...,I 0(i) ,...,-I 0(j) ,...,0 (n) )；
(32) Calculating the theoretical value of the current of the branch of the grounding grid I k(1) ＝G b A T U n(1) ，I k(2) ＝G b A T U n(2) ，...，I k(m) ＝G b A T U n(m) And accordingly obtaining the theoretical value of the current vector of the branch circuit of the grounding grid as I k ＝(I k(1) ,I k(2) ,...,I k(m) )；
(33) According to the sections of the grounding gridThe theoretical value of point voltage is calculated by injecting DC current I into each accessible node 0 The theoretical value of the port voltage between each reachable node and the reference node is U = (U) (1) ,U (2) ,……U (m) )；
(34) Calculating theoretical values of the port resistances of the accessible nodes of the grounding grid according to ohm's law: r ij(1) ＝U (1) /I 0 ，R ij(2) ＝U (2) /I 0 ，...，R ij(m) ＝U (m) /I 0 And obtaining the theoretical value vector R of the port resistance of the grounding grid according to the above ij ＝(R ij(1) ,R ij(2) ,...,R ij(m) )；
(35) Obtaining detection parameters of the grounding grid according to the step 2, and calculating actual values R 'of port resistances of the accessible nodes and the reference nodes of the grounding grid' ij(1) ＝U’ (1) /I 0 ，R’ ij(2) ＝U’ (2) /I 0 ，...，R’ ij(m) ＝U’ (m) /I 0 And obtaining the actual value vector R 'of the port resistance of the grounding grid according to the actual value vector R' ij ＝(R’ ij(1) ,R’ ij(2) ,...,R’ ij(m) )；
(36) Calculating the change quantity of the actual value and the theoretical value of the port resistance of the grounding grid: delta R ij ＝R’ ij -R ij ；
(37) Establishing a relation between the resistance variation of the grounding network branch and the resistance variation of the port through the Taylor's theorem:
Figure GDA0003806272220000103
wherein, Δ R ij Is the variation quantity of the actual value and the theoretical value of the port resistance of the grounding grid calculated in (36), delta R k Is the amount of resistance change, I, of the branch of the grounding grid to be solved k Is the theoretical value of the current vector of the earth network branch, I ', calculated in (32)' k Is the actual value of each branch current after corrosion and the resistance variation quantity Delta R of the branch resistor k In connection with, I 0 Is the value of the direct current injected between the reach node and the reference node;
the step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by using a Lasso theory to obtain a solution result, wherein the solution result comprises the following steps:
(41) Setting the initial value of each branch current after corrosion to ensure that
Figure GDA0003806272220000111
Then the resistance equation of the grounding grid branch in the third step) is changed into
Figure GDA0003806272220000112
(42) Randomization initialization
Figure GDA0003806272220000113
Supply of Δ R k Randomly taking an initial value
Figure GDA0003806272220000114
(43) From
Figure GDA0003806272220000115
At the beginning
Figure GDA0003806272220000116
Until now, in turn find
Figure GDA0003806272220000117
Figure GDA0003806272220000118
The solution of (a) is as follows:
Figure GDA0003806272220000119
wherein | | | purple hair 1 Is the regularization of L1 and,
Figure GDA00038062722200001110
λ∈[0,1]the penalty coefficient can be specified artificially;
in solving for
Figure GDA00038062722200001111
When the temperature of the water is higher than the set temperature,
Figure GDA00038062722200001112
are all constants;
sequentially find out
Figure GDA00038062722200001113
(44) Obtained by last calculation
Figure GDA00038062722200001114
Updating
Figure GDA00038062722200001115
And recalculate
Figure GDA00038062722200001116
Figure GDA00038062722200001117
Thereby obtaining the branch current value at the next iteration
Figure GDA00038062722200001118
(45) Will be updated
Figure GDA00038062722200001119
Substitution equation
Figure GDA00038062722200001120
(46) Judgment of
Figure GDA00038062722200001121
(wherein epsilon is a set error constant) and if not, returning to (43) for circulation; if it is
Figure GDA00038062722200001122
Is established, then
Figure GDA00038062722200001123
The optimal solution of the equation of the resistance variation of the branch of the grounding grid and the resistance variation of the port is obtained;
(47) Calculating the solution of the actual value of the branch resistance of the grounding network
Figure GDA0003806272220000121
The step 5: based on the solution result, the corrosion degree of the transformer substation grounding grid is graphically displayed, and the method comprises the following steps:
according to the actual value of the branch resistance of the grounding grid obtained by the step 4, calculating the change multiple of the branch resistance
Figure GDA0003806272220000122
Wherein k =1,2., b, b represents the total number of grounding grid branches;
based on preset evaluation standard, according to branch resistance change multiple
Figure GDA0003806272220000123
Evaluating the corrosion degree of each branch of the grounding network to obtain an evaluation result;
graphically displaying the evaluation result, wherein the slightly corroded branch is represented by green, the moderately corroded branch is represented by yellow, and the severely corroded branch is represented by red;
and drawing an actual corrosion diagnosis result graph of each branch of the grounding grid according to the corrosion degree of each branch of the grounding grid, and outputting the graph.
The working principle and the beneficial effects of the technical scheme are as follows:
the topology, nodes and branch numbers of the grounding network of the embodiment are shown in fig. 1, a rectangle represents a grounding network branch, a circle represents a grounding network node, and a red circle represents a grounding network reachable node, in the embodiment, it is assumed that corrosion occurs in branch 4 and branch 8, the branch resistance is 10 ohms, other branches are in good condition, the branch resistance is 1 ohm, the reachable nodes are 3,6,9 and 15 nodes, and the reference node is 16 nodes.
(1) And establishing a structural relation matrix of the grounding grid of the transformer substation, and acquiring basic parameters of the grounding grid. And analyzing the topological structure of the transformer substation grounding grid according to the design drawing of the transformer substation grounding grid, and establishing an incidence matrix A for describing the grounding grid structure. The incidence matrix A describes the connection relation between the nodes and the branches of the grounding network, the 'rows' of the matrix A represent the node elements of the grounding network, and the 'columns' of the matrix A represent the branch elements of the grounding network. Taking a branch corresponding to the element as a reference direction from left to right and from top to bottom, wherein for each element of A, when the branch corresponding to the element leaves a node corresponding to the element according to the reference direction, the element takes +1; when the branch corresponding to the element enters the node corresponding to the element according to the reference direction, taking-1 as the element; when the branch corresponding to the element is not associated with the node corresponding to the element, the element takes 0.
Taking 4x4 node network data as an example, an incidence matrix a of the network is calculated, and the size of the incidence matrix is 16x24, that is, the network has 16 nodes and 24 branches.
Figure GDA0003806272220000124
Figure GDA0003806272220000131
(2) Obtaining branch resistance vector R of the grounding grid according to the basic condition of the grounding grid k ＝(R 1 ,R 2 ,...R i ,...,R 24 )＝(1,1,...,1,...,1)。
(3) And carrying out simulation on the actual condition of the grounding grid to obtain the operation parameters of the actual grounding grid. And (3) establishing a simulation model by utilizing Matlab, setting No. 16 nodes as reference nodes, and selecting 3,6,9 and 15 nodes as reachable nodes. Direct current source I injected between each accessible node and reference node 0 Set to 10A, simulation results that reachable nodes 3,6,9,15 are respectively injected with direct current I 0 Port voltage vector of time U '= (U' (3) ,U’ (6) ,U’ (9) ,U’ (15) )＝(14.7743，14.1934，17.0429，7.0356)。
(4) Normal case (rotten)Before etching) a lower branch conductance matrix of
Figure GDA0003806272220000132
I.e. the main diagonal is R k The remainder are 24 × 24 squares of 0. From G n ＝AG b A T Obtaining a 16x16 node conductance matrix, and then
Figure GDA0003806272220000133
A 16x4 node voltage matrix is obtained. In which the nodes inject a current matrix I n Comprises the following steps:
Figure GDA0003806272220000134
(5) Obtaining a branch current matrix I under normal conditions (before corrosion) k ＝G b A T U n And is a 24x4 matrix. The theoretical value of the current matrix of the grounding grid branch is I k ＝(I k(3) ,I k(6) ,I k(9) ,I k(15) )。
Figure GDA0003806272220000141
(6) Calculating the DC current I injected at each node 0 Before etching, the theoretical value of the port voltage between each accessible node and the reference node. U = (U) (3) ,U (6) ,U (9) ,U (15) )＝(14.5982，12.9464，14.5982，7.0089)。
(7) Calculating actual values R 'of port resistances of the reachable node and the reference node of the grounding network according to the obtained voltage detection parameter of the port of the grounding network' ij(3) ＝U’ (3) /I 0 ，R’ ij(6) ＝U’ (6) /I 0 ，R’ ij(9) ＝U’ (9) /I 0 ，R’ ij(15) ＝U’ (15) /I 0 Obtaining the actual value vector R 'of the port resistance of the grounding grid' ij ＝(R’ ij(3) ,R’ ij(6) ,R’ ij(9) ,R’ ij(15) )＝(1.47743，1.41934，1.70429，0.70356)。
(8) Calculating theoretical values of the port resistances of the accessible nodes of the grounding grid according to ohm's law: r ij(3) ＝U (3) /I 0 ，R ij(6) ＝U (6) /I 0 ，R ij(9) ＝U (9) /I 0 ，R ij(15) ＝U (15) /I 0 Obtaining the theoretical value vector R of the port resistance of the grounding grid ij ＝(R ij(3) ,R ij(6) ,R ij(9) ,R ij(15) )＝(1.45982，1.29464，1.45982，0.70089)。
(9) Calculating the change quantity of the actual value and the theoretical value of the port resistance of the grounding grid: delta R ij ＝R’ ij -R ij ＝(△R ij(3) ,△R ij(6) ,△R ij(9) ,△R ij(15) )＝(0.0176，0.1247，0.2445，0.0027)。
(10) During initial iterative calculation, the post-corrosion circuit current I 'is calculated' k Equal to the current I of the branch before corrosion k That is to say order
Figure GDA0003806272220000151
Then converting Δ R ij 、I k 、I 0 Substituting into the fault diagnosis equation set of the grounding grid
Figure GDA0003806272220000152
In (1), four underdetermined equations are obtained.
Figure GDA0003806272220000153
Calling lasso function in Matlab so that
Figure GDA0003806272220000154
Minimum, get the first solution
Figure GDA0003806272220000155
Obtaining the branch variation of the first Lasso iterative computation
Figure GDA0003806272220000161
Comprises the following steps: (0,0,0,0.6369,0,0,0,2.1800,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0).
By
Figure GDA0003806272220000162
Can obtain
Figure GDA0003806272220000163
Comprises the following steps: (1,1,1,1.6369,1,1,1,3.1800,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1,1).
(11) Obtained by last calculation
Figure GDA0003806272220000164
Updating
Figure GDA0003806272220000165
And recalculate
Figure GDA0003806272220000166
Thereby obtaining the branch current value at the next iteration
Figure GDA0003806272220000167
(12) Will be updated
Figure GDA0003806272220000168
Substitution equation
Figure GDA0003806272220000169
Solving by using a Lasso optimization method
Figure GDA00038062722200001610
Is/are as follows
Figure GDA00038062722200001611
(13) Judgment of
Figure GDA00038062722200001612
(where ε is the set error constant) is true, where ε is set to 0.01. If not, returning to the step (11) for circulation; if it is
Figure GDA00038062722200001613
Is established, then
Figure GDA00038062722200001614
The method is an optimal solution of the equation of the resistance variation of the branch of the grounding network and the resistance variation of the port. Calculating the solution of the actual value of the branch resistance of the grounding network
Figure GDA00038062722200001615
In this example, after 12 iterations, the convergence condition is satisfied
Figure GDA00038062722200001616
The resulting equation is solved as:
△R k ＝(0，0，0，7.2231，0，0，0，7.8930，0，0，0，0，0，0，0，0，0，0，0，0，0，0，0，0)。
according to
Figure GDA00038062722200001617
The calculated value for calculating the resistance value of each branch of the actual grounding grid is as follows:
Figure GDA00038062722200001618
(14) Calculating the change multiple P of the branch resistance according to the actual value of the branch resistance of the grounding grid obtained by solving k ＝R’ k /R k (k =1,2.., b.b represents the total number of ground net branches).
P k ＝R’ k /R k ＝(1，1，1，8.2231，1，1，1，8.8930，1，1，1，1，1，1，1，1，1，1，1，1，1，1，1，1)。
(15) According to branch resistance change multiple P k ＝R’ k /R k The corrosion degree of each branch of the grounding network is evaluated, and the preset evaluation criteria are shown in the following table:
Figure GDA0003806272220000171
as shown in fig. 3. And (3) graphically displaying the corrosion degree of the grounding grid branch, wherein the slightly corroded branch is represented by green, the moderately corroded branch is represented by yellow, and the severely corroded branch is represented by red. And drawing an actual corrosion diagnosis result graph of each branch of the grounding grid according to the corrosion degree of each branch of the grounding grid.
The invention utilizes Lasso theory to compress characteristics, which not only can solve the over-fitting problem, but also can directly compress unimportant variables into 0 and delete the influence of invalid variables (uncorroded branches). Can achieve the purpose of extracting effective branch resistance variation quantity delta R in the parameter reduction process k (corroded branch). Not only can the more accurate fault diagnosis of the grounding grid be realized, but also the variable selection (dimension reduction) can be realized. The method solves the blindness of the corrosion diagnosis of the grounding grid, can accurately diagnose and position the fault without excavating soil in a large area, provides reference for replacing the grounding grid or not and selecting the excavation position, and further reduces the operation and maintenance cost of the on-site grounding grid. And the corrosion diagnosis result of the grounding grid is visualized and convenient to apply through graphical display.
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, as shown in fig. 4, the grounding grid corrosion diagnosis method based on the Lasso theory further comprises the following steps:
step 6: training a corrosion coping model, formulating a coping strategy according to the corrosion degree of the transformer substation grounding grid based on the corrosion coping model, and carrying out corresponding coping processing based on the coping strategy.
The working principle and the beneficial effects of the technical scheme are as follows:
when the grounding grid of the transformer substation is corroded, timely coping treatment is needed; based on machine learning technology, training can learn the model that manual analysis transformer substation's ground net corrodes the condition and carry out the reply and handle, corrodes the reply model promptly, based on the corruption reply model of training, according to the degree of corrosion, formulates the reply strategy, carries out corresponding reply and handles.
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, wherein in the step 6, a corrosion coping model is trained, and the method comprises the following steps:
acquiring a plurality of first corrosion countermeasures and acquiring a counterpart corresponding to the first corrosion countermeasures;
acquiring a coping type corresponding to the counterparty, wherein the coping type comprises: internal coping and external coping;
when the corresponding type of the corresponding party is internal responding, acquiring an experience degree value corresponding to the corresponding party;
if the empirical degree value is less than or equal to a preset first threshold value, rejecting the corresponding first corrosion coping event;
when the corresponding type of the corresponding party is external corresponding, acquiring a credit degree value corresponding to the corresponding party;
if the credit degree value is less than or equal to a preset second threshold value, rejecting the corresponding first corrosion coping event;
when the first corrosion coping events needing to be removed are all removed, the remaining first corrosion coping events are removed to be used as second corrosion coping events;
carrying out rationality analysis on the second corrosion coping event to obtain a rational value;
if the reasonable value is greater than or equal to a preset third threshold value, taking the corresponding second corrosion coping event as a third corrosion coping event;
and performing model training according to the third corrosion coping event based on a preset model training algorithm to obtain a corrosion coping model.
The working principle and the beneficial effects of the technical scheme are as follows:
when the corrosion coping model is trained, a first corrosion coping event, namely a process record for manually analyzing the corrosion condition of the grounding grid of the transformer substation for coping processing, needs to be acquired, so that learning and training are facilitated based on a machine learning technology, but in order to ensure the training quality of the corrosion coping model and ensure the suitability of coping strategy formulation, the first corrosion coping event needs to be screened; the coping types of the counterparty (the manual counterparty for analyzing and coping with processing commands) corresponding to the first corrosion coping event are divided into internal coping (professional in the transformer substation company) and external coping (professional in other transformer substation companies); when the coping type is internal coping, the experience degree of the coping party can be accurately traced (records can be checked), a corresponding experience degree value is obtained, and if the experience degree value is smaller, a corresponding first corrosion coping event is removed; when the coping type is external coping, verifying the general quality of the corrosion coping event historically provided by the coping party, namely acquiring a credit degree value, and if the credit degree value is smaller, rejecting a corresponding first corrosion coping event; and performing model training according to the third corrosion coping event which is removed and remained on the basis of a preset model training algorithm (machine learning algorithm).
The invention provides a grounding grid corrosion diagnosis method based on a Lasso theory, which is used for carrying out rationality analysis on a second corrosion coping event to obtain a reasonable value and comprises the following steps:
acquiring a plurality of expert nodes, and simultaneously acquiring an evaluation value for reasonably evaluating the second corrosion coping event by the expert nodes;
acquiring expert weights corresponding to the expert nodes, giving the evaluation values corresponding to the expert weights, and acquiring target values;
and accumulating and calculating the target value to obtain a reasonable value.
The working principle and the beneficial effects of the technical scheme are as follows:
when the rationality of the second corrosion coping event is analyzed, a plurality of expert nodes are set, the expert nodes correspond to a grounding grid corrosion coping expert, and the rationality of the second corrosion coping event is evaluated by the expert nodes to obtain an evaluation value; the larger the expert weight of the expert node is, the higher the rationality of rationality evaluation performed by the expert node is, and the expert weight (multiplication) corresponding to the evaluation value is given to the expert node to obtain a target value; and accumulating and summing the target values to obtain a reasonable value, so that the accuracy of obtaining the reasonable value is improved.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims (8)

1. A grounding grid corrosion diagnosis method based on the Lasso theory is characterized by comprising the following steps:
step 1: establishing a structural relation matrix of a transformer substation grounding grid, and simultaneously acquiring basic parameters of the transformer substation grounding grid;
step 2: detecting a transformer substation grounding grid to obtain detection parameters;
and step 3: establishing a corrosion diagnosis equation set of the grounding grid of the transformer substation based on the structural relationship matrix, the basic parameters and the detection parameters;
and 4, step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by utilizing a Lasso theory to obtain a solution result;
and 5: graphically displaying the corrosion degree of the grounding grid of the transformer substation based on the solving result;
step 6: training a corrosion coping model, making a coping strategy according to the corrosion degree of the transformer substation grounding grid based on the corrosion coping model, and performing corresponding coping processing based on the coping strategy;
in step 6, training a corrosion countermeasure model includes:
acquiring a plurality of first corrosion coping events, and acquiring a coping party corresponding to the first corrosion coping events;
acquiring a coping type corresponding to the coping party, wherein the coping type comprises: internal coping and external coping;
when the corresponding type of the corresponding party is internal corresponding, acquiring an experience degree value corresponding to the corresponding party;
if the empirical degree value is less than or equal to a preset first threshold value, rejecting the corresponding first corrosion coping event;
when the corresponding type of the corresponding party is external corresponding, acquiring a credit degree value corresponding to the corresponding party;
if the credit degree value is less than or equal to a preset second threshold value, rejecting the corresponding first corrosion coping event;
when the first corrosion coping events needing to be removed are all removed, the remaining first corrosion coping events are removed to be used as second corrosion coping events;
carrying out rationality analysis on the second corrosion coping event to obtain a rational value;
if the reasonable value is greater than or equal to a preset third threshold value, taking the corresponding second corrosion coping event as a third corrosion coping event;
and performing model training according to the third corrosion coping event based on a preset model training algorithm to obtain a corrosion coping model.
2. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 1, wherein in the step 1, establishing a structural relationship matrix of the substation grounding grid comprises:
analyzing a topological structure of a design drawing of the transformer substation grounding grid, and establishing an incidence matrix A for describing a structural relationship of the transformer substation grounding grid;
the incidence matrix A describes the connection relation between nodes and branches of the transformer substation grounding network, the row of the matrix A represents a node element of the grounding network, and the column of the matrix A represents a branch element of the grounding network; taking the reference direction from left to right and from top to bottom, and taking the element as +1 for each element of A when the branch corresponding to the element leaves the node corresponding to the element according to the reference direction; when the branch corresponding to the element enters the node corresponding to the element according to the reference direction, taking-1 as the element; when the branch corresponding to the element is not associated with the node corresponding to the element, the element takes 0.
3. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 2, wherein the step 1 of obtaining the basic parameters of the grounding grid of the substation comprises:
calculating the nominal resistance value R of the branch according to the length of the branch of the transformer substation grounding grid and the grounding material adopted by the branch i ＝ρl i /s i Wherein i =1,2,3., b, b is the total number of grounding grid branches, ρ is the resistivity of the grounding grid branch metal, and l i Is the length of the branch of the counterpoise, s i The sectional area of the branch metal of the grounding grid is obtained, and the branch nominal resistance vector R of the grounding grid is obtained according to the sectional area k ＝(R 1 ,R 2 ,...R i ,...,R b )；
By branch nominal resistance vector R k Get ground net branch conductance matrix
Figure FDA0003836309880000021
Further obtaining a grounding grid node conductance matrix G n ＝AG b A T Wherein, the subscript n represents the total number of the nodes of the grounding network.
4. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 1, wherein the step 2: detecting the transformer substation grounding grid to obtain detection parameters, comprising:
taking a node with a leading-out wire on a transformer substation ground grid as a reachable node, selecting any node in the transformer substation ground grid as a reference node, and injecting direct current I between the reference node and the reachable node 1 0 Measuring a port voltage value U 'between the reachable node 1 and the reference node' (1) ；
Selecting the next available node and injecting a DC current I between the next available node and the reference node 0 Measuring a port voltage value U 'between the reachable node and a reference node' (2) ；
And repeating the operation on the rest reachable nodes in sequence, and recording the corresponding port voltage value U' (m) M is the number of reachable nodes, get injectedDirect current I 0 Port voltage vector U ' = (U ' of the case ' (1) ,U′ (2) ,…,U′ (m) )。
5. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 3, wherein the step 3: establishing a transformer substation grounding grid corrosion diagnosis equation set based on the structural relationship matrix, the basic parameters and the detection parameters, wherein the equation set comprises the following steps:
(31) According to the network topology of the transformer substation grounding network and the grounding network node conductance matrix G calculated in the step 1, the reference node selected in the step 2 is used n ＝AG b A T Calculating the DC current I injected into each node in step 2 0 Under the condition, the voltage theoretical value of each node of the transformer substation grounding grid is as follows:
Figure FDA0003836309880000031
Figure FDA0003836309880000032
in which I n Is the injection node n current vector, I n ＝(0 (1) ,0 (2) ,...,I 0(i) ,...,-I 0(j) ,...,0 (n) )；
(32) Calculating the theoretical value of the current of the branch of the grounding grid I k(1) ＝G b A T U n(1) ，I k(2) ＝G b A T U n(2) ，...，I k(m) ＝G b A T U n(m) And accordingly obtaining the theoretical value of the current vector of the branch circuit of the grounding grid as I k ＝(I k(1) ,I k(2) ,...,I k(m) )；
(33) According to the theoretical voltage value of each node of the grounding grid, calculating the direct current I injected into each accessible node 0 The theoretical value of the port voltage between each reachable node and the reference node is U = (U) (1) ,U (2) ,……U (m) )；
(34) And calculating theoretical values of the port resistances of the accessible nodes of the grounding grid according to ohm's law: r ij(1) ＝U (1) /I 0 ，R ij(2) ＝U (2) /I 0 ，...，R ij(m) ＝U (m) /I 0 And obtaining the theoretical value vector R of the port resistance of the grounding grid according to the above ij ＝(R ij(1) ,R ij(2) ,...,R ij(m) )；
(35) Obtaining detection parameters of the grounding grid according to the step 2, and calculating actual values R 'of port resistances of the accessible nodes and the reference nodes of the grounding grid' ij(1) ＝U′ (1) /I 0 ，R′ ij(2) ＝U′ (2) /I 0 ，...，R′ ij(m) ＝U′ (m) /I 0 And obtaining the actual value vector R 'of the port resistance of the grounding grid according to the actual value vector R' ij ＝(R′ ij(1) ,R′ ij(2) ,...,R′ ij(m) )；
(36) Calculating the change quantity of the actual value and the theoretical value of the port resistance of the grounding grid: delta R ij ＝R′ ij -R ij ；
(37) Establishing a relation between the resistance variation of the grounding network branch and the resistance variation of the port through the Taylor's theorem:
Figure FDA0003836309880000041
wherein, Δ R ij Is the variation of the actual value and the theoretical value of the port resistance of the grounding grid calculated in (36), delta R k Is the amount of resistance change of the branch of the grounding grid to be solved, I k Is the theoretical value of the current vector of the earth network branch, I ', calculated in (32)' k Is the actual value of each branch current after corrosion and the resistance variation quantity Delta R of the branch resistor k In connection with, I 0 Is the value of the dc current injected between the reach node and the reference node.
6. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 5, wherein the step 4: iteratively solving the corrosion diagnosis equation set of the transformer substation grounding grid by using a Lasso theory to obtain a solution result, wherein the solution result comprises the following steps:
(41) Setting the initial value of each branch current after corrosion to make
Figure FDA0003836309880000042
Then the resistance equation of the grounding grid branch in the third step) is changed into
Figure FDA0003836309880000043
(42) Randomization initialization
Figure FDA0003836309880000044
Supply of Δ R k Randomly taking an initial value
Figure FDA0003836309880000045
(43) From
Figure FDA0003836309880000046
At the beginning
Figure FDA0003836309880000047
Until now, in turn find
Figure FDA0003836309880000048
Figure FDA0003836309880000049
The solution of (a) is as follows:
Figure FDA00038363098800000410
wherein | | | purple hair 1 Is the regularization of L1 and,
Figure FDA0003836309880000051
λ∈[0,1]is a penalty coefficient;
at the solution of
Figure FDA0003836309880000052
When the temperature of the water is higher than the set temperature,
Figure FDA0003836309880000053
are all constants;
sequentially find out
Figure FDA0003836309880000054
(44) Obtained by last calculation
Figure FDA0003836309880000055
Updating
Figure FDA0003836309880000056
And recalculate
Figure FDA0003836309880000057
Figure FDA0003836309880000058
Thereby obtaining the branch current value at the next iteration
Figure FDA0003836309880000059
(45) Will be updated
Figure FDA00038363098800000510
Substitution equation
Figure FDA00038363098800000511
(46) Judgment of
Figure FDA00038363098800000512
If yes, wherein epsilon is a set error constant, if not, returning to (43) for circulation; if it is
Figure FDA00038363098800000513
Is established, then
Figure FDA00038363098800000514
The optimal solution of the equation of the resistance variation of the branch of the grounding grid and the resistance variation of the port is obtained;
(47) Calculating the solution of the actual value of the branch resistance of the grounding network
Figure FDA00038363098800000515
7. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 6, wherein the step 5: based on the solution result, the corrosion degree of the transformer substation grounding grid is graphically displayed, and the method comprises the following steps:
according to the actual value of the branch resistance of the grounding grid obtained by the step 4, calculating the change multiple of the branch resistance
Figure FDA00038363098800000516
Wherein k =1,2., b, b represents the total number of grounding grid branches;
based on preset evaluation standard, according to branch resistance change multiple
Figure FDA00038363098800000517
Evaluating the corrosion degree of each branch of the grounding network to obtain an evaluation result;
graphically displaying the evaluation result, wherein slightly corroded branches are represented by green, moderately corroded branches are represented by yellow, and severely corroded branches are represented by red;
and drawing an actual corrosion diagnosis result graph of each branch of the grounding grid according to the corrosion degree of each branch of the grounding grid, and outputting the graph.
8. The method for diagnosing corrosion of a grounding grid based on the Lasso theory as claimed in claim 1, wherein the analyzing rationality of the second corrosion countermeasure event to obtain a rational value comprises:
acquiring a plurality of expert nodes, and simultaneously acquiring an evaluation value for reasonably evaluating the second corrosion coping event by the expert nodes;
acquiring expert weights corresponding to the expert nodes, giving the evaluation values corresponding to the expert weights, and acquiring target values;
and accumulating and calculating the target value to obtain a reasonable value.
CN202210350908.XA 2022-04-02 2022-04-02 Grounding grid corrosion diagnosis method based on Lasso theory Active CN114707283B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202210350908.XA CN114707283B (en) 2022-04-02 2022-04-02 Grounding grid corrosion diagnosis method based on Lasso theory

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202210350908.XA CN114707283B (en) 2022-04-02 2022-04-02 Grounding grid corrosion diagnosis method based on Lasso theory

Publications (2)

Publication Number Publication Date
CN114707283A CN114707283A (en) 2022-07-05
CN114707283B true CN114707283B (en) 2022-10-21

Family

ID=82172861

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202210350908.XA Active CN114707283B (en) 2022-04-02 2022-04-02 Grounding grid corrosion diagnosis method based on Lasso theory

Country Status (1)

Country Link
CN (1) CN114707283B (en)

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115982914B (en) * 2023-02-16 2023-06-02 华东交通大学 Grounding grid corrosion evaluation method and system based on elastic grid theory

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104865487A (en) * 2014-08-20 2015-08-26 上海交通大学 Sub-area fault diagnosis method for transformer station grounding network
CN105445615A (en) * 2015-11-12 2016-03-30 有能集团有限公司 Corrosion diagnosis method for transformer station grounding network
CN109102131A (en) * 2018-10-26 2018-12-28 中国农业科学院农业信息研究所 A kind of optimization method of the Soybean production based on big data
CN109324241A (en) * 2017-08-01 2019-02-12 国网辽宁省电力有限公司电力科学研究院 A kind of grounding net of transformer substation corrosion diagnosis method for early warning and system
CN110032827A (en) * 2019-04-30 2019-07-19 清华大学 Current elements 3-d inversion method based on algebra elastic network(s) regularization method
CN111262246A (en) * 2020-03-16 2020-06-09 国网天津市电力公司电力科学研究院 Method for rapid model establishment and accurate corrosion diagnosis of transformer substation grounding grid
CN111830361A (en) * 2019-04-18 2020-10-27 中国石油化工股份有限公司 Oil field tank field grounding grid fault detection device

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2817915C (en) * 2010-11-16 2020-02-18 Matco Services Inc. Method for protecting electrical poles and galvanized anchors from galvanic corrosion
CN114062966A (en) * 2021-11-16 2022-02-18 国网上海市电力公司 Grounding grid corrosion fault diagnosis method based on improved fruit fly optimization algorithm

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN104865487A (en) * 2014-08-20 2015-08-26 上海交通大学 Sub-area fault diagnosis method for transformer station grounding network
CN105445615A (en) * 2015-11-12 2016-03-30 有能集团有限公司 Corrosion diagnosis method for transformer station grounding network
CN109324241A (en) * 2017-08-01 2019-02-12 国网辽宁省电力有限公司电力科学研究院 A kind of grounding net of transformer substation corrosion diagnosis method for early warning and system
CN109102131A (en) * 2018-10-26 2018-12-28 中国农业科学院农业信息研究所 A kind of optimization method of the Soybean production based on big data
CN111830361A (en) * 2019-04-18 2020-10-27 中国石油化工股份有限公司 Oil field tank field grounding grid fault detection device
CN110032827A (en) * 2019-04-30 2019-07-19 清华大学 Current elements 3-d inversion method based on algebra elastic network(s) regularization method
CN111262246A (en) * 2020-03-16 2020-06-09 国网天津市电力公司电力科学研究院 Method for rapid model establishment and accurate corrosion diagnosis of transformer substation grounding grid

Non-Patent Citations (4)

* Cited by examiner, † Cited by third party
Title
A Diagnosis of Grounding Grid Corrosion Defects Based on Branch Voltage Disturbance;Manling Dong et al;《IEEE Access》;20200213;第8卷;全文 *
基于智能优化算法的接地网故障诊断;赵可欣;《中国优秀硕士学位论文全文数据库电子期刊 工程科技II辑》;20150415;第2015年卷(第4期);全文 *
基于电网络理论的变电站接地网腐蚀及断点诊断方法;许磊 等;《电工技术学报》;20121031;第27卷(第10期);参见第2节 *
邻近点梯度法与交替方向乘子法求解LASSO的性能比较分析;陆萍;《现代计算机》;20151130;参见第0-1节 *

Also Published As

Publication number Publication date
CN114707283A (en) 2022-07-05

Similar Documents

Publication Publication Date Title
CN106248569A (en) A kind of corrosion diagnosis of grounding grid method based on endogenous formula EIT
CN114707283B (en) Grounding grid corrosion diagnosis method based on Lasso theory
CN107561407B (en) Distributed transformer substation grounding grid detection and evaluation method
CN104898024B (en) The Failure Diagnosis of Substation Ground Network method of comprehensive surface potential and magnetic induction intensity
CN111262246A (en) Method for rapid model establishment and accurate corrosion diagnosis of transformer substation grounding grid
CN109324241B (en) Corrosion diagnosis early warning method and system for transformer substation grounding grid
Zheng et al. The theory and implementation of corrosion diagnosis for grounding system
CN104142455A (en) Grounding grid corrosion fault diagnosis method based on Tellegen theorem
CN114154766B (en) Method and system for early warning vulnerability of power grid under dynamic prediction of thunder and lightning
CN110428185B (en) Pseudo measurement model-based robust state estimation method for electricity-heat interconnection comprehensive energy system
CN106295911A (en) A kind of grid branch parameter evaluation method based on chromatographic assays
CN104965134B (en) Grounding net of transformer substation surface potential distribution calculation method based on echo state network
CN107632231B (en) Transformer substation grounding grid corrosion fault online diagnosis method using multiple excitation sources
CN105445615A (en) Corrosion diagnosis method for transformer station grounding network
CN115982914B (en) Grounding grid corrosion evaluation method and system based on elastic grid theory
CN114660387A (en) Lightning arrester monitoring method based on leakage current sensor and BP neural network algorithm
CN104849620A (en) Grounding grid fault diagnosis method based on BP neural network
CN117039890B (en) Network attack detection-oriented power distribution network prediction auxiliary interval state estimation method
CN110265906B (en) Transformer substation grounding grid state evaluation method and computer system
CN117535669A (en) Fixed-point accurate cathode protection corrosion prevention method for grounding grid
Liu et al. Optimized corrosion diagnosis of large-scale grounding grid
CN107505536B (en) Transformer substation grounding grid earth surface potential distribution calculation method considering multiple metal pipelines
CN105425049A (en) Method of testing geodetic network earthing resistance
CN112565180B (en) Power grid defense method, system, equipment and medium based on moving target defense
Davoudi Sensitivity analysis of power system estimation regarding to network parameter uncertainties

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant