A rapid electromagnetic nondestructive detection method for PCCP pipeline broken wires

Abstract

The invention discloses a rapid electromagnetic nondestructive detection method for PCCP pipeline broken wires, comprising building a PCCP pipeline network map navigation system for determining a detection area and a pipeline group, establishing a PCCP pipeline broken wire feature model library for broken wire diagnosis, and PCCP pipeline broken wire detection; PCCP pipeline broken wire detection includes pipeline and pipeline robot initialization, autonomous driving, data acquisition, broken wire diagnosis and output results; the invention realizes automation and intelligence of PCCP pipeline broken wire detection by combining the pipeline robot with electromagnetic nondestructive testing equipment, and does not require on-site operation by professionals. The invention has the advantages of fast detection speed, low cost, high detection accuracy, data traceability, high degree of automation, high degree of visualization, high degree of intelligence, strong adaptability, strong scalability, etc., can effectively increase the single-day detection distance of PCCP pipeline broken wires by more than 10 times and enhance the detection quality, greatly reduce the detection cost, and provide data support and decision-making basis for enterprises.

Description

Technical Field

[0001] The present invention relates to the technical field of PCCP pipeline detection, and in particular to a method and system for rapid electromagnetic nondestructive detection of broken wires in PCCP pipelines. Background Art

[0002] PCCP pipe, also known as prestressed concrete pipe, is a pipe commonly used for water transport, drainage, and long-distance medium transportation. It is widely used in many projects due to its high strength, good corrosion resistance and long service life. However, since the pipe is buried underground, various problems may occur in PCCP pipes over time, due to environmental influences and the pressure inside the pipe. Therefore, regular inspections are required to eliminate potential defects such as cracks, corrosion, and prestress loss. Timely measures can avoid sudden pipe ruptures to ensure public safety and extend the service life of the pipe. The most common problem with PCCP pipes is pipe rupture caused by broken wires. There are no early signs of this problem, and pipe ruptures can cause huge economic losses and maintenance costs.

[0003] PCCP pipeline broken wire detection technology is an orthogonal electromagnetic detection technology commercialized by Canada's Pure Technology in 1997 based on the principle of far-field eddy current electromagnetic detection. It was later acquired by Xylem of the United States. Currently, the world still uses Xylem's PCCP pipeline broken wire detection standard: the accuracy of detecting pipeline broken wires is 5 broken wires (100mm interval), and the alarm threshold is set at 50 broken wires (40-50 broken wires indicate a dangerous state of PCCP pipe burst). The daily detection distance is between 1.5 kilometers and 5.6 kilometers. Professionals are required to push the electromagnetic non-destructive testing equipment inside the pipeline for operation. The theoretical optimal speed of the orthogonal electromagnetic detection equipment is 0.5 meters per second (14.4 kilometers per day).

[0004] At present, more than 26,000 kilometers of PCCP pipelines are in use in China, and the growth rate is expanding at 10% per year. The domestic PCCP pipeline broken wire detection technology is still in the imitation stage. The technical route, operation method and products are basically copied or continued from the product series of Xylem Company in the United States, without any original features; it is completely dependent on on-site operation by professionals, lacks data accumulation, and has no credible verification method for the detection results; the price of PCCP pipeline detection by domestic companies is about 40,000 yuan per kilometer, forcing Xylem Company to reduce its domestic charging price to 80,000 yuan per kilometer, but compared with Xylem Company's detection plan, domestic detection methods have no advantages in detection accuracy and cost-effectiveness. According to the need for inspection and maintenance every 5 years, at least 5,200 kilometers of PCCP pipelines need to be inspected every year, which is equivalent to an annual inspection fee of more than 200 million yuan (calculated at 40,000 yuan per kilometer); how to increase the single-day detection distance and break through the theoretical detection speed bottleneck of orthogonal electromagnetic detection equipment has become the key to reducing detection costs. Summary of the invention

[0005] In view of this, the present invention provides a rapid electromagnetic nondestructive detection method for PCCP pipeline broken wires, which effectively solves the problems of slow detection speed and high cost of current PCCP pipeline detection methods.

[0006] To achieve the above object, the present invention provides a rapid electromagnetic nondestructive detection method for PCCP pipeline broken wires, comprising the following steps:

[0007] S1. Build a PCCP pipeline network map;

[0008] S2. Establish a PCCP pipeline broken wire feature model library;

[0009] S201, using a pipeline robot equipped with a calibrated electromagnetic nondestructive testing device to automatically scan the PCCP pipeline in the pipeline according to the testing task, controlling the orthogonal electromagnetic method detection control circuit to obtain PCCP pipelines in various wire-broken states, and adjusting the excitation magnetic field frequency, the interaxial distance between the excitation coil and the receiving coil, and the acquisition frequency in the receiving coil according to the pipeline position;

[0010] S202, using magnetic field finite element method to simulate PCCP pipelines with different pipe types and material compositions, and establishing a broken wire model library with directionality and integrated simulation of pipe type, pipe diameter and pipeline material;

[0011] Combined with electromagnetic nondestructive testing equipment to collect actual pipeline inspection initialization data, the model is trained through machine learning to establish a personalized broken wire model library;

[0012] S203, establishing a PCCP pipeline fault characteristic model;

[0013] S3. Conduct PCCP pipeline broken wire detection;

[0014] S301, the pipeline robot is equipped with electromagnetic nondestructive testing equipment to generate a pipeline group task data packet according to the task plan and initialize it, obtain the signal-to-noise ratio difference characteristics of the PCCP pipeline port and the pipeline body through the detection sensor, and obtain the pipeline port model through training;

[0015] S302, the pipeline robot autonomously controls the speed in each section of the pipeline according to the task package data, the inertial navigation system and the pipeline port model; autonomously drives in the PCCP pipeline to be inspected and corrects the error generated by the previous pipeline operation when reaching the pipeline port;

[0016] S303, the electromagnetic nondestructive testing equipment collects data and diagnoses broken wires according to the pipeline position and the corresponding broken wire model library, and automatically retests and verifies abnormal data;

[0017] S304, the detection results are bound to the PCCP pipeline that matches the GPS coordinate system and output to the system platform for visual display and generation of a broken wire report.

[0018] Preferably, building a PCCP pipeline network map includes the following steps:

[0019] S101. Collect and import PCCP pipeline network data;

[0020] S102, reorganizing the pipe network according to the PCCP pipe network data, taking a single PCCP pipe as a basic unit, sorting the PCCP pipes according to the longitude and latitude of the pipes, binding the position information, arranging them, and establishing a unique code for the PCCP pipes that can be retrieved;

[0021] S103, visualize the PCCP pipeline network, including the main pipeline display and local pipeline network display, in order to facilitate the planning of PCCP pipeline broken wire detection tasks, and locally display the pipeline network operation characteristics, pipe type and pipe diameter according to the detection task; display the number and location of the abnormal pipeline in the detection result, and the color change indicates the abnormal pipeline broken wire status; the pipeline map displays the pipeline status, and directly clicks on the abnormal pipeline to display the specific broken wire data;

[0022] Preferably, the PCCP pipeline network data includes PCCP pipeline number, pipeline length, pipe diameter, pipeline prestressing, nodes, turning points, intersections, longitude and latitude and elevation of the installation location and PCCP pipeline network GIS data.

[0023] Preferably, the pipe network image is targeted at a map image, and an image stitching technology alignment method is used to make the PCCP pipe network image and the map image plane coincide with each other, including image orientation and image pixel size. The pipe network can be displayed separately in a planar 2D form or a local form.

[0024] Preferably, using the magnetic field finite element method to establish a directional broken wire model library includes the following steps:

[0025] Discretize the magnetic field analysis area into a finite number of small units, each unit is a finite element;

[0026] Select the appropriate network type according to the analysis requirements, including triangular and quadrilateral finite elements;

[0027] Set the vector distribution according to the physical model and calculate the initial magnetic field strength;

[0028] The Maxwell equations are converted into finite element equations and solved. The expression of Maxwell equations in the PCCP pipeline structure is:

[0029] ;

[0030] ;

[0031] ;

[0032] ;

[0033] in, represents the magnetic field strength, represents the current density, represents the electric field strength, represents the magnetic flux density, represents the electric flux density, represents the charge density;

[0034] E. Adjust the constitutive equation of the PCCP pipeline structure and materials to simulate different pipe types, and repeat steps 3-5; the constitutive equation of the PCCP pipeline structure and materials is expressed as:

[0035] ;

[0036] ;

[0037] ;

[0038] in, represents the magnetic permeability, represents the magnetic susceptibility, represents the dielectric constant, Indicates conductivity.

[0039] Preferably, partial least squares method is used for wire breakage diagnosis, and principal component analysis is used to screen out the closest wire breakage model features in the wire breakage model library for feature data with obvious differences. The pipeline robot executes the retest instruction, retests in the opposite direction and repeats the wire breakage diagnosis.

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] The present invention realizes the automation and intelligence of PCCP pipeline broken wire detection by combining the pipeline robot with the electromagnetic nondestructive testing equipment; the pipeline robot can autonomously control the speed of driving, is not affected by human factors, greatly improves the detection speed, and the daily detection distance can reach more than 10 times; at the same time, it reduces the dependence on professionals, reduces labor costs, and greatly reduces the detection fee per kilometer;

[0042] The present invention improves the accuracy of the detection results through the broken wire feature model library and intelligent diagnosis algorithm, and the detection results are visualized, the broken wire position and number are intuitively displayed, and a broken wire diagnosis report is generated, which is convenient for users to understand and analyze the detection results;

[0043] The present invention is applicable to PCCP pipelines of different pipe types and material compositions, and can be used to train existing models based on actual collected data, adjust detection parameters, and calibrate algorithm models to improve detection efficiency and accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] FIG1 is a schematic diagram of a PCCP pipeline network of the present invention;

[0045] Figure 2 The PCCP pipeline data structure diagram of the present invention;

[0046] Figure 3 This is a basic module diagram of the PCCP pipeline network system platform of the present invention;

[0047] Figure 4 A schematic diagram of signal interference and characteristics of the PCCP pipeline port and pipeline body of the present invention;

[0048] Figure 5 The optimal speed related parameters and principle diagram of the electromagnetic detection equipment of the present invention;

[0049] Figure 6 The PCCP pipeline simulation circuit and the PCCP pipeline winding wire and broken wire simulation schematic diagram of the present invention;

[0050] Figure 7 A flow chart for building a PCCP pipeline network of the present invention; DETAILED DESCRIPTION

[0051] In order to further explain the technical means and effects adopted by the present invention to achieve the predetermined invention purpose, the specific implementation mode, structure, characteristics and effects of the present invention are described in detail below in combination with the accompanying drawings and preferred embodiments.

[0052] Embodiment 1:

[0053] In order to improve the speed of PCCP pipeline detection, reduce the dependence on professionals, reduce labor costs, and improve the accuracy of PCCP pipeline detection results, the present invention provides the following technical solutions: a rapid PCCP pipeline broken wire electromagnetic nondestructive detection method, comprising the following steps:

[0054] S1. Build a PCCP pipeline network map, including the following steps:

[0055] S101. Collect and import PCCP pipeline network data, including PCCP pipeline number, pipeline length, pipe diameter, pipeline prestressing, nodes, turning points, intersections, longitude and latitude and elevation of installation locations, and PCCP pipeline network GIS data;

[0056] S102, reorganizing the pipe network according to the PCCP pipe network data, taking a single PCCP pipe as a basic unit, sorting the PCCP pipes according to the longitude and latitude of the pipes, binding the position information, arranging them, and establishing a unique code for the PCCP pipes that can be retrieved;

[0057] PCCP pipeline parameters are also pipeline model library pipeline data structures, including data formats and contents, such as Figure 2 As shown, it includes the original model (modeling of factory or new PCCP pipelines), the broken wire model (the test platform simulates broken wire failure by cutting the PCCP pipeline steel wire), the port model (PCCP pipeline socket and spigot simulate broken wire failure) used to collect data from the PCCP pipeline network broken wire detection equipment for real-time processing (comparison and identification), the personalized model (based on the original model, the actual PCCP pipeline state model), the fault feature model (collecting actual fault information modeling), the pipeline port and pipeline body signal-to-noise ratio model (identifying the port position), except for the pipeline port and pipe body signal-to-noise ratio model, the others are used to assist in real-time broken wire diagnosis and analysis;

[0058] The establishment of the signal-to-noise ratio model of the pipeline port and pipeline body is completed through testing on the test platform, such as Figure 4As shown in the figure; the PCCP pipeline network is formed by connecting the front and rear pipe sockets. Due to the large thickness of the steel ring of the socket, there is a significant difference between the signal received after the electromagnetic signal penetrates the steel ring and the electromagnetic signal obtained by normally penetrating the pipe body. The difference in electromagnetic signals has obvious regularity and repetitive characteristics, which can be used to determine the position of the front and rear sockets and sockets of the PCCP pipeline; after testing on the experimental platform, the electromagnetic non-destructive testing equipment itself can determine the position of the PCCP pipeline socket and socket by normally receiving changes in the electromagnetic field during movement, and also determine the position of the PCCP pipeline body; since the length of a single PCCP pipeline is known, the operating speed of the electromagnetic non-destructive testing equipment is known, and the sensitivity of the change of the electromagnetic field is far greater than that of the mechanical Displacement (operating speed), so the change signal of the electromagnetic field at the PCCP pipeline port combined with the pipeline length can be modeled; the pipeline port and pipeline body signal-to-noise ratio model includes the PCCP pipeline starting position (pipeline socket), the pipeline body starting position, and the pipeline spigot position. By obtaining the change of the electromagnetic field and the pipeline port and pipeline body signal-to-noise ratio model algorithm in real time, the pipeline robot inertial navigation system can be effectively corrected to ensure that the cumulative error does not exceed the error caused by running in a single pipe; it can be used to control the driving speed of the pipeline robot; it can be used to control the offset distance of the excitation and detection coils of the electromagnetic detection equipment, the excitation signal frequency, and the acquisition frequency of the acquisition point phase, to generate the best combination parameters to optimize (improve) the "best" speed;

[0059] S103, visualize the PCCP pipeline network, including the main pipeline display and local pipeline network display, in order to facilitate the planning of PCCP pipeline broken wire detection tasks, and locally display the pipeline network operation characteristics, pipe type and pipe diameter according to the detection task; display the number and location of the abnormal pipeline in the detection result, and the color change indicates the abnormal pipeline broken wire status; the pipeline map displays the pipeline status, and directly clicks on the abnormal pipeline to display the specific broken wire data;

[0060] The pipeline network image uses the map image as the target, and uses image stitching technology to align the PCCP pipeline network image and the map image plane, including the image orientation and image pixel size. The pipeline network can be displayed separately in a flat 2D form or a local form. The pipeline network can integrate pipeline prestressing points and add editable labels. The pipeline network can also assist the PCCP pipeline network robot navigation.

[0061] S2. Establish a PCCP pipeline broken wire feature model library:

[0062] S201, using a pipeline robot equipped with a calibrated electromagnetic nondestructive testing device to automatically scan the PCCP pipeline in the pipeline according to the detection task, controlling the orthogonal electromagnetic detection control circuit to obtain PCCP pipelines in various broken wire states, adjusting the excitation magnetic field frequency, the interaxial distance between the excitation coil and the receiving coil, and the acquisition frequency in the receiving coil according to the pipeline position, and establishing the PCCP pipeline original model and the broken wire model;

[0063] S202. Use the magnetic field finite element method to simulate PCCP pipelines with different pipe types and materials, collect actual pipeline data (test initialization data) in combination with electromagnetic nondestructive testing equipment, and establish a directional broken wire model library that integrates pipe type, pipe diameter and pipeline material simulation through machine learning training model; each time the actual collected test results do not have broken wire features, they will be supplemented to the original pipeline model in a correction manner according to the pipeline position to improve the personalized original pipeline model;

[0064] The magnetic field finite element method includes the following steps:

[0065] Discretize the magnetic field analysis area into a finite number of small units, each unit is a finite element;

[0066] Select the appropriate network type according to the analysis requirements, including triangular and quadrilateral finite elements;

[0067] Set the vector distribution according to the physical model and calculate the initial magnetic field strength;

[0068] The Maxwell equations are converted into finite element equations and solved. The expression of Maxwell equations in the PCCP pipeline structure is:

[0069] ;

[0070] ;

[0071] ;

[0072] ;

[0073] in, represents the magnetic field strength, represents the current density, represents the electric field strength, represents the magnetic flux density, represents the electric flux density, represents the charge density;

[0074] Adjust the constitutive equation of the PCCP pipeline structure and material to simulate different pipe types, and repeat steps 3-5; the constitutive equation of the PCCP pipeline structure and material is expressed as:

[0075] ;

[0076] ;

[0077] ;

[0078] in, represents the magnetic permeability, represents the magnetic susceptibility, represents the dielectric constant, represents electrical conductivity;

[0079] At the same time, the electromagnetic field propagating in the PCCP pipeline wire should satisfy the law of conservation of charge and the continuity equation:

[0080] ;

[0081] The basic principle of electromagnetic nondestructive testing technology for PCCP pipelines in low-frequency electromagnetic field (also known as eddy current magnetic field) is expressed;

[0082] The electromagnetic nondestructive testing analysis method essentially solves the propagation process of the electromagnetic field in the pipeline structure under known excitation magnetic fields and boundary conditions. The use of low-frequency excitation magnetic fields for nondestructive testing can greatly simplify the complexity of the electromagnetic field propagation process in the pipeline structure; combined with the electromagnetic field finite element method, the partial differential equations can be solved for structures with different pipe diameters and material compositions such as PCCP pipelines to achieve the simulation purpose, so that the PCCP pipeline characteristic model is more scalable, reducing the model's dependence on the PCCP pipeline diameter and material (type), so that the pipeline model can provide intelligent services for broken wire detection during actual PCCP pipeline network inspection after a brief on-site data collection and model training (initialization);

[0083] S203, establish a PCCP pipeline fault feature model; the PCCP pipeline fault feature model refers to the abnormalities of the same type of PCCP pipeline detected in other pipeline networks and verified, or the re-discussion and tracing data after the pipe burst event (with a single PCCP pipeline as the basic unit), and the feature vector obtained by principal component analysis is regarded as the fault feature model;

[0084] The establishment of the pipeline model library is based on the use of the calibration electromagnetic non-destructive testing equipment transmitting coil on the PCCP pipeline experimental platform to generate an alternating excitation magnetic field in the closed loop of the equally spaced steel wire wrapped around the PCCP pipeline to induce a secondary magnetic flux (far-field eddy current effect) which is converted into an electrical signal by the detection coil (detection device). Figure 6 The left is the equivalent circuit of the electromagnetic nondestructive testing equipment for PCCP pipelines. The principle is that the PCCP pipeline is wrapped with steel wire to form an equidistant closed loop. The transmitting coil of the detection device generates an alternating excitation magnetic field, which induces a secondary magnetic flux M in the wrapped steel wire. This magnetic flux is induced by the detection coil (detection device). Converted into voltage signal ;When wire breakage occurs When the magnetic flux is affected by the impedance change, the induced current in the steel wire changes , the magnetic flux M changes accordingly, affecting the received signal Distortion caused by Amplitude and phase changes; as a basis for detection and analysis, it is necessary to conduct The amplitude and phase are modeled separately in the signal characteristics under normal conditions and the change characteristics under broken wire conditions. Can simulate the number of broken wires; Figure 6 Right The simulation PCCP pipeline winding wire schematic diagram, with the help of the experimental platform can simulate normal and various broken wire combination conditions, Figure 6 Right ①、 Figure 6 Right ② respectively represents the steel wire evenly wound on the PCCP pipe (spiral from the pipe socket to the pipe spigot); Figure 6 Right ③ indicates N relays on the PCCP pipeline The connected steel wire can control the relay switch through the control circuit to simulate various wire breaking situations.

[0085] S3. Rapid PCCP pipeline broken wire detection:

[0086] S301. The pipeline robot is equipped with electromagnetic nondestructive testing equipment, various detection sensors and data docking modules, so that it can travel quickly (including variable speed) and smoothly independently of the pipeline environment. It generates pipeline group task data packets according to the task plan and initializes them. According to the task plan, the local task of the pipeline network (ROI) is imported into the robot navigation system. The local task can be abstracted as a set of sorted PCCP pipeline number sequences. The PCCP pipeline number is used to obtain (explore) all parameters of the pipeline from the algorithm model library. The signal-to-noise ratio difference characteristics of the PCCP pipeline port and the pipeline body are obtained through the detection sensor as the basis for the pipeline robot to change speed in the pipeline.

[0087] The optimal speed-related parameters of electromagnetic detection equipment are composed of the offset distance of the excitation and detection coils of the electromagnetic detection equipment, the excitation signal frequency, and the phase acquisition frequency of the acquisition point, such as Figure 5As shown; subject to the magnetic field signal area of ​​the PCCP pipeline wrapped with steel wire, such as the different magnetic field signal qualities of the pipeline port and the pipe body, timely and accurate acquisition of the magnetic field signal area of ​​the PCCP pipeline wrapped with steel wire can adjust the "measurement point phase acquisition times" of the electromagnetic non-destructive testing equipment to improve the optimal detection speed; in the PCCP pipeline port area, the magnetic field signal interference is large (low signal-to-noise ratio), and adjusting the "excitation and detection coil offset distance" and "excitation signal frequency" of the electromagnetic non-destructive testing equipment can improve the detection accuracy and sensitivity; since the PCCP pipeline port area accounts for 20% of the entire pipeline, optimizing the 80% area of ​​the pipeline can effectively improve the optimal detection speed x;

[0088] S302, the pipeline robot autonomously controls the speed in each section of the pipeline according to the task package data, the inertial navigation system and the pipeline port model; autonomously drives in the PCCP pipeline to be inspected and corrects the error generated by the previous pipeline operation when reaching the pipeline port;

[0089] S303. The electromagnetic nondestructive testing equipment collects data according to the pipeline position (pipeline port and pipe body) and the corresponding broken wire model library, and uses the partial least squares method to diagnose broken wires. For abnormal data, the pipeline robot is driven to automatically retest and verify in reverse. For features with obvious differences, the closest broken wire model features are screened out in the broken wire model library by the principal component analysis method. The pipeline robot executes the retest instruction, retests in the opposite direction and repeats the broken wire diagnosis. The diagnostic results of the same pipeline in the two directions are independent of each other and are compared and verified with each other, so as to achieve the purpose of improving the accuracy of diagnosis;

[0090] The electromagnetic nondestructive testing equipment adjusts the excitation magnetic field frequency, the interaxial distance between the excitation coil and the receiving coil, and the acquisition frequency in the receiving coil according to the position of the robot in the pipeline, thereby improving the theoretical detection speed of the orthogonal electromagnetic method detection equipment, thereby adjusting the robot's travel speed;

[0091] S304, the detection results are bound to the PCCP pipeline that matches the GPS coordinate system and output to the system platform for visual display and generation of a broken wire report.

[0092] Example 2: Building a PCCP pipeline network map navigation system

[0093] The PCCP pipeline network structure framework constitutes a pipeline network, which can be displayed together with the map to obtain geographical location reference information, such as Figure 7 As shown in the operation process, the preparation work is to design and lay the pipeline drawings Figure 7 -① Establish a table based on the identity of the pipeline (including pipeline length, nodes, bends, cross pipes, valves, etc.), Figure 7 -②; The pipelines arranged by identity must have at least the following information Figure 7-①: Pipeline UID, pipe length (node, turning point, turning point, intersection), pipe diameter, starting point longitude, latitude, end point longitude, latitude; the pipe network structure component module provides a data import mechanism to import the above tables into the system program to reorganize the pipe network structure. Figure 7 -③; The reorganization of the pipe network structure can be simply understood as a process of using a city map with a longitude and latitude coordinate system as a "base" and putting the pipes with longitude and latitude together like a "puzzle" Figure 7 -④.

[0094] Since the longitude and latitude information of the pipe network structure is obtained through design and installation, and the longitude and latitude azimuth of the map do not represent the image in the same "collection" method; therefore, the pipes and map images "calculated" based on the longitude and latitude of the starting and ending points have differences in pixel size (clarity), misalignment (position deviation), and orientation (azimuth). In order to discuss them together (matching after reorganization) and process the data, image geometry matching and alignment processing is required to achieve alignment with the map after the pipe network structure is reorganized, and then image processing and display operations such as image unification and mutual conversion can be performed; the image matching conversion algorithm can use nonlinear geometric transformation, or nonlinear three-dimensional difference method; the "nonlinear" here is to generate a differential function by fitting the terrain through quadratic curve regression, and the relationship between the matching conversion of the pipe network structure and the map image can be established through nonlinear geometric transformation. Figure 7 -⑤.

[0095] After the PCCP pipeline network structure (pipeline) is aligned with the map image, the reorganized pipeline network structure image can be mapped to the map image for display, or the local segment (area) can be mapped to the map for display. The key is to give the area for the inspection task planning; generally, ROI defines a rectangle through 4 vertices, and the 4 vertices will find corresponding points in the pipeline network structure image to form a corresponding rectangle. The pipeline network structure image within the rectangle will be imported into the new display space. In the pipeline network structure, the PCCP pipeline diameter or the PCCP pipeline laying years can also be used as the basic unit for ROI and map matching display.

[0096] The PCCP pipeline network determines the number of all pipelines in the task planning area ROI, and sorts them according to the installation position, obtaining a group of continuous PCCP pipeline groups. The starting point of the pipeline can be determined according to the direction of water flow. The serial number of each pipeline in the pipeline group can be used to retrieve the PCCP pipeline number, which corresponds to the broken wire feature model of the pipeline in the PCCP pipeline network model database. The pipeline group and the PCCP pipeline network model database information corresponding to all pipelines in the pipeline group constitute the inspection task; a 22-kilometer PCCP pipeline network inspection task involves 3,667 pipelines (pipeline network / pipeline: 22000 / 6=3667), assuming that the broken wire feature model data space of each pipeline is 512K (reference Figure 2), the data volume of the inspection task data packet is approximately 1,878MByte. The pipeline robot obtains the PCCP pipeline group sorted in the order of installation through the inspection task data packet as the basis for its inertial navigation, and the pipeline broken wire characteristics and related data retrieved from each pipeline number assist the electromagnetic non-destructive testing equipment in data collection, intelligent diagnosis, and feedback of pipeline position information to the pipeline robot to achieve the purpose of correcting the operating position deviation.

[0097] Example 3: Establishing a PCCP pipeline broken wire characteristic model

[0098] The PCCP pipeline broken wire model needs to be established with the help of a test platform. First, determine the PCCP pipeline, and use electromagnetic modeling equipment to scan the entire PCCP pipeline in two directions (considering that the actual detection may be from upstream to downstream or / and from downstream to upstream), and establish the original model. Simulate the broken wire state: Cut a section in the middle of the PCCP pipeline to expose 50 wires ( Figure 6 Cut off the wires, install controllable switch relays, cooperate with control circuits, and use software to control the wire connection and wire breaking status.

[0099] Broken wire 1 model, starting from the middle, control the first wire relay to disconnect to simulate wire breakage, use the same electromagnetic modeling equipment to scan the entire PCCP pipeline in two directions to establish broken wire 1 model; Broken wire 3 model, upstream of the first broken wire, disconnect two wire relays to simulate wire breakage, repeat the above scan to establish broken wire 3 model; Broken wire 5 model, downstream of the first broken wire, disconnect two wire relays to simulate wire breakage, repeat the above scan to establish broken wire 5 model; Broken wire 10 model, upstream of the five broken wires, disconnect five wire electrical appliances to simulate wire breakage, repeat the above scan to establish broken wire 10 model; Broken wire 1 5 models, downstream of 10 broken wires, disconnect 5 steel wires in succession to simulate broken wires, repeat the above scan, and establish a broken wire 15 model; and so on, until 50 steel wires are cut (or the upper limit of broken wires designed by the model); each operation of cutting the steel wire generates a model; the total number of disconnected steel wires is: 1, 3, 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, and the corresponding broken wire models are generated; considering that the actual detection can start from any direction, the model needs to meet the directionality, so the upstream and downstream directions need to be considered when modeling, and the discontinuous broken wire model can be achieved by adjusting the simulated broken wire state through the control software.

[0100] Example 4: Practical operation of PCCP pipeline network broken wire detection

[0101] The same type of PCCP pipeline network with a diameter of 2m between pumping stations A and B at 22km needs to be regularly inspected and evaluated for broken wires. Since it is the first inspection, it is necessary to build a PCCP pipeline network map on the system platform according to the original design and laying drawings of the pipeline, and generate a task data packet for the inspection pipeline group according to the task planning. The data packet is "implanted" (for example, by inserting a USB disk or directly downloading it through the 4G network) into the pipeline robot and electromagnetic non-destructive testing equipment (robot inspection system) that perform the inspection task.

[0102] The robot detection system is embedded into the "starting point" of the PCCP pipeline network between pump station A and pump station B by construction personnel through the pipeline wellhead; after assembly and testing, the robot detection system is repeatedly tested and initialized in the first two sections of the pipeline, and the PCCP pipeline in this section of the pipeline network model library is corrected according to the collected data to establish a personalized model. On the basis of the existing broken wire model, the robot detection system corrects and matches the original model through field collection, so that the electromagnetic non-destructive testing equipment can generate a personalized model through real-time collection of PCCP pipeline detection data. After initialization, the robot detection system automatically performs broken wire detection according to the PCCP pipeline sequence in the task data packet, and uses the partial least squares method to analyze whether there is a broken wire change feature; if the feature (difference) is obvious, the principal component analysis is used to find the most matching feature model by which the feature is close to the broken wire model feature in the broken wire model library. Then the robot detection system sends a retest instruction, retests from the opposite direction, repeats the above diagnostic steps, finds the most matching feature model, and binds the detection results to the PCCP pipeline (number) to complete the quantitative broken wire diagnosis of the PCCP pipeline.

[0103] The robot detection system travels in the pipeline network, and calculates the driving position based on the pipeline length and speed, which corresponds to the PCCP pipeline number in the PCCP pipeline group (the so-called inertial navigation). The port model is used to determine when the robot travels into each new PCCP pipeline, and the position error is corrected to achieve the best driving speed and collection frequency for the single-day detection distance.

[0104] After the inspection task is completed, the robot inspection system outputs the inspection results to the system platform. The PCCP pipeline number with broken wire characteristics retrieves its longitude and latitude according to its pipeline group sorting position, fits it to the PCCP pipeline network map to complete the broken wire detection visualization, and can generate a broken wire diagnosis report for the end customer. The customer plans the operation and maintenance plan based on the marking (geographic location) of the broken wire pipeline on the PCCP pipeline network map.

[0105] Therefore, the PCCP pipeline network broken wire detection minimizes the involvement of professionals. The whole process has automatic driving, real-time, and intelligent detection and diagnosis, which greatly improves the detection speed and achieves the goal of increasing the daily detection distance by 10x.

[0106] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Although the present invention has been disclosed as a preferred embodiment as above, it is not used to limit the present invention. Any technical personnel in this field can make some changes or modify the technical contents disclosed above into equivalent embodiments without departing from the scope of the technical solution of the present invention. However, any brief modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A rapid electromagnetic nondestructive detection method for PCCP pipeline broken wires, characterized in that: The following steps are involved: S1. Build a PCCP pipeline network map; S2. Establish a PCCP pipeline broken wire feature model library; S201, using a pipeline robot equipped with a calibrated electromagnetic nondestructive testing device to automatically scan the PCCP pipeline in the pipeline according to the detection task, controlling the orthogonal electromagnetic detection control circuit to obtain PCCP pipelines in various broken wire states, adjusting the excitation magnetic field frequency, the interaxial distance between the excitation coil and the receiving coil, and the acquisition frequency in the receiving coil according to the pipeline position, and establishing the PCCP pipeline original model and the broken wire model; S202, using magnetic field finite element method to simulate PCCP pipelines with different pipe types and material compositions, and establishing a directional broken wire model library; Combined with electromagnetic nondestructive testing equipment to collect actual pipeline inspection initialization data, a machine learning training model is used to establish a directional broken wire model library that integrates pipe type, pipe diameter and pipeline material simulation; S203, establishing a PCCP pipeline fault characteristic model; S3. Conduct PCCP pipeline broken wire detection; S301. The pipeline robot is equipped with electromagnetic nondestructive testing equipment and detection sensors, generates and initializes the pipeline group task data packet according to the task plan, obtains the signal-to-noise ratio difference characteristics of the PCCP pipeline port and the pipeline body through the detection sensor, and obtains the pipeline port model through training; S302, the pipeline robot autonomously controls the speed in each section of the pipeline according to the task package data, the inertial navigation system and the pipeline port model; autonomously drives in the PCCP pipeline to be inspected and corrects the error generated by the previous pipeline operation when reaching the pipeline port; S303, the electromagnetic nondestructive testing equipment collects data and diagnoses broken wires according to the pipeline position and the corresponding broken wire model library, and automatically retests and verifies abnormal data; S304, the detection results are bound to the PCCP pipeline that matches the GPS coordinate system and output to the system platform for visual display and generation of a broken wire report.

2. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 1, characterized in that: Building a PCCP pipeline network map includes the following steps: S101. Collect and import PCCP pipeline network data; S102, reorganizing the pipe network according to the PCCP pipe network data, taking a single PCCP pipe as a basic unit, sorting the PCCP pipes according to the longitude and latitude of the pipes, binding the position information, arranging them, and establishing a unique code for the PCCP pipes that can be retrieved; S103, visualized PCCP pipeline network; It includes the main pipeline display and local pipeline network display, and displays the operation characteristics, pipe types and diameters of the pipeline network locally according to the detection task.

3. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 2, characterized in that: The PCCP pipeline network data includes PCCP pipeline number, pipeline length, pipe diameter, pipeline prestressing, nodes, turning points, intersections, longitude and latitude and elevation of the installation location, and PCCP pipeline network GIS data.

4. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 2, characterized in that: The pipe network image uses the map image as a target and uses image stitching technology alignment method to make the PCCP pipe network image and the map image plane consistent, including image orientation and image pixel size. The pipe network can be displayed separately in a planar 2D form or a local form.

5. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 1, characterized in that: The use of the magnetic field finite element method to establish a broken wire model library with directionality and integrated pipe type, pipe diameter and pipeline material simulation includes the following steps: Discretize the magnetic field analysis area into a finite number of small units, each unit is a finite element; Select the appropriate network type according to the analysis requirements, including triangular and quadrilateral finite elements; Set the vector distribution according to the physical model and calculate the initial magnetic field strength; The Maxwell equations are converted into finite element equations and solved. The expression of Maxwell equations in the PCCP pipeline structure is: ； ； ； ； in, represents the magnetic field strength, represents the current density, represents the electric field strength, represents the magnetic flux density, represents the electric flux density, represents the charge density; Adjust the constitutive equation of the PCCP pipeline structure and material to simulate different pipe types, and repeat steps 3-5; the constitutive equation of the PCCP pipeline structure and material is expressed as: ； ； ； in, represents the magnetic permeability, represents the magnetic susceptibility, represents the dielectric constant, Indicates conductivity.

6. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 1, characterized in that: By initially collecting PCCP pipeline data, the pipeline and broken wire models are trained to generate a personalized model.

7. A rapid electromagnetic nondestructive testing method for PCCP pipeline broken wires according to claim 1, characterized in that: The partial least squares method is used for broken wire diagnosis. The principal component analysis method is used to screen out the closest broken wire model features in the broken wire model library for features that are significantly different from the original model data of the PCCP pipeline. The pipeline robot executes the retest instruction, retests in the opposite direction and repeats the broken wire diagnosis.

Images