CN-121994687-A - Intelligent evaluation and quantitative classification method for corrosion degree of grounding grid

CN121994687ACN 121994687 ACN121994687 ACN 121994687ACN-121994687-A

Abstract

The invention discloses an intelligent evaluation and quantitative grading method for corrosion degree of a grounding grid, relates to the technical field of corrosion detection of the grounding grid, and solves the problems that in the prior art, the corrosion degree evaluation is ambiguous and grading standards are absent in the grounding grid corrosion detection technology based on a transient electromagnetic method. The method comprises the steps of firstly establishing a reusable apparent resistivity reference database on a standard grounding grid, providing a reliable reference system for quantitative comparison, then rapidly locking abnormal grids through double-index similarity evaluation to avoid blind encryption detection, finally converting discrete observation data into a continuous resistivity distribution model by utilizing a two-dimensional inversion algorithm, creatively providing a corrosion index calculation formula, converting abstract resistivity difference into visual dimensionless indexes, realizing synchronous quantification of corrosion area, depth and severity, providing accurate decision support capability for power grid operation and maintenance departments, and remarkably improving engineering practical value of detection results.

Inventors

BIAN MEIHUA
LU ZHANQIANG
DENG SHANQUAN
HE YUYIN
ZHU JUNWEI
CHEN HENG
PENG JIANING
ZHANG XINGSEN
LIU GUICHAN
LI JUNHUA

Assignees

广西电网有限责任公司电力科学研究院

Dates

Publication Date: 20260508
Application Date: 20260119

Claims (10)

1. The intelligent evaluation and quantitative grading method for the corrosion degree of the grounding grid is characterized by comprising the following steps of: S1, establishing a standard apparent resistivity curve set, namely detecting the center of each grid of the non-corroded grounding grid by using a transient electromagnetic detection device, obtaining a secondary induced voltage, and calculating to obtain the standard apparent resistivity curve set; S2, detecting the diagnosed grounding grid, namely detecting the center of each grid of the diagnosed grounding grid by using a transient electromagnetic detection device, obtaining secondary induced voltage, and calculating to obtain a apparent resistivity curve of each grid center; S3, judging whether each grid of the diagnosed grounding grid is likely to be corroded, namely comparing the apparent resistivity curve of the center of each grid with a standard apparent resistivity curve set, and judging whether each grid is likely to be corroded; S4, performing dense-point detection on grids which may have corrosion by using a transient electromagnetic detection device; S5, calculating to obtain apparent resistivity distribution conditions of the grid underground; s6, imaging the apparent resistivity distribution condition; And S7, observing the apparent resistivity difference, and judging the corrosion position of the grounding grid based on the resistivity difference.
2. The method for intelligently evaluating and quantitatively grading corrosion degree of grounding network according to claim 1, wherein in step S1, the standard apparent resistivity is calculated as follows: in the formula, Representing a standard apparent resistivity; Indicating vacuum permeability; representing the transmit coil area; Representing the equivalent radius; the time of the sample is indicated as the moment of sampling, Representing the emission current; Representing the induced voltage.
3. The method for intelligently evaluating and quantitatively grading the corrosion degree of the grounding grid according to claim 2, wherein the method for obtaining the secondary induced voltage in the step S2 and the method for calculating the apparent resistivity are the same as those in the step S1.
4. The method for intelligently evaluating and quantitatively grading the corrosion degree of the grounding grid according to claim 1, wherein the step S3 is specifically as follows: S301, evaluating the similarity of curves, namely calculating root mean square error and correlation coefficient; s302, judging corrosion conditions according to the set threshold value, and further outputting a corrosion grid set 。
5. The method for intelligently evaluating and quantitatively grading the corrosion degree of the grounding grid according to claim 1, wherein the step S4 is specifically as follows: s401, carrying out encryption network measurement layout in the suspected grids marked in the S3 according to the set corresponding measuring point spacing and measuring point number; s402, obtaining the induction voltage of the encryption measuring point And requires a measurement accuracy, where the measurement accuracy is higher than the accuracy of the preceding step; s403, calculating to obtain Constructing a high-density observation data set 。
6. The method for intelligently evaluating and quantitatively grading the corrosion degree of the grounding grid according to claim 1, wherein the step S5 is specifically as follows: s501, setting a two-bit inversion objective function: in the formula, Representing a model parameter vector, m=ln (ρ); Representing an observation data vector; representing a forward operator; representing a data weight matrix; representing a model smoothing matrix; λ represents a regularization factor; Representing a reference model; s502, performing inversion operation to obtain a two-dimensional resistivity distribution model The inversion procedure is as follows: initial model: ; And (5) iterative updating: ; And (3) terminating the condition that the gradient norm or the iteration number reaches a set threshold.
7. The method for intelligently evaluating and quantitatively grading the corrosion degree of the grounding grid according to claim 1, wherein the step S701 is specifically as follows: S701, setting a relative resistivity threshold and a gradient threshold, and identifying a corrosion body; s702, after determining corrosion, performing corrosion degree evaluation: s703, setting a grading standard: s704, outputting a final report, integrating all the information of S1-S6, and outputting the final report including the corrosion degree And a hierarchical, suggested comprehensive report.
8. The method for intelligently evaluating and quantitatively grading corrosion degree of grounding grid according to claim 7, wherein grading standards and suggestions are set as follows: Light: Suggesting enhanced monitoring; : : 。
9. A computer-readable storage medium, characterized in that the computer-readable storage medium comprises a stored program, wherein the program, when run, controls a device in which the computer-readable storage medium is located to perform the method for intelligently evaluating and quantitatively grading the corrosion level of a ground network according to any one of claims 1 to 8.
10. A processor for running a program, wherein the program runs to perform the method for intelligently assessing and quantitatively grading the corrosion level of a ground network according to any one of claims 1 to 8.

Description

Intelligent evaluation and quantitative classification method for corrosion degree of grounding grid Technical Field The invention relates to the technical field of corrosion detection of a grounding grid, in particular to an intelligent evaluation and quantitative classification method for the corrosion degree of the grounding grid. Background The grounding grid of the power system is used as a key facility for guaranteeing safe and stable operation of the power grid and bears important functions such as fault current discharge, overvoltage protection, electromagnetic shielding and the like. In the power grid scenes such as transformer substations, transmission towers and the like, the grounding grid is buried underground for a long time, and the multiple threats of soil corrosion, electrochemical corrosion and stray current corrosion are commonly faced, so that the sectional area of a conductor is reduced, the grounding resistance is increased, and the safety accidents such as equipment damage, personal electric shock and the like can be possibly caused when the sectional area of the conductor is serious. According to statistics, about 40% of the grounding grids in China have corrosion problems with different degrees, and the corrosion has the characteristics of strong concealment, slow development and difficult direct observation. The traditional detection method mainly relies on regular excavation spot check or ground electrical parameter measurement, and is low in efficiency, high in cost and incapable of comprehensively evaluating the overall corrosion state. In recent years, transient electromagnetic method gradually becomes the main technical direction of nondestructive detection of a grounding grid by virtue of the advantages of non-contact, high sensitivity, large detection depth and the like, but how to realize intelligent identification of corrosion positions and accurate quantification of damage degree based on electromagnetic response data is still a technical bottleneck which puzzles the operation and maintenance departments of the power grid. Current grounding grid corrosion detection technology based on transient electromagnetic method generally faces the fatal defect of fuzzification of corrosion degree evaluation and missing of grading standard. The traditional method is mainly in a qualitative judgment level, namely whether corrosion is judged by comparing abnormal resistivity of local areas, but a quantitative mapping relation between resistivity difference and corrosion amount cannot be established, and the corrosion severity cannot be scientifically classified. The defect causes that on-site operation and maintenance personnel can not formulate a precise maintenance strategy according to a detection report, when the resistivity of a certain area is higher, whether light corrosion needs to be monitored in an enhanced mode or heavy corrosion needs to be immediately excavated and replaced cannot be judged, and a conservative strategy can be adopted only by experience, so that excessive maintenance or hidden danger omission is caused. Especially in the large-scale operation and maintenance scene of the power grid, the lack of quantitative classification means that the differential operation and maintenance resource allocation cannot be realized, and all suspected corrosion areas need to be verified by inputting a large amount of manpower and material resources, so that the application value and popularization efficiency of the detection technology are severely restricted In view of this, there is a need for an intelligent assessment and quantitative classification method for the extent of corrosion of a ground network. Disclosure of Invention Aiming at the problems of fuzzy corrosion degree evaluation and lack of grading standards commonly faced by the grounding grid corrosion detection technology based on a transient electromagnetic method in the prior art, the invention provides an intelligent evaluation and quantitative grading method for the corrosion degree of a grounding grid, which can construct a progressive diagnosis framework of standard curve group establishment, preliminary abnormal screening, encryption fine detection and inversion imaging quantification, and fundamentally solves the problem that the corrosion degree cannot be quantitatively graded in industry. The specific technical scheme is as follows: An intelligent evaluation and quantitative classification method for corrosion degree of a grounding grid comprises the following steps: S1, establishing a standard apparent resistivity curve set, namely detecting the center of each grid of the non-corroded grounding grid by using a transient electromagnetic detection device, obtaining a secondary induced voltage, and calculating to obtain the standard apparent resistivity curve set; S2, detecting the diagnosed grounding grid, namely detecting the center of each grid of the diagnosed grounding grid by using a transient elect