A pipe network anti-leakage optical fiber sensing precise positioning system
By employing equal-lead spiral laying and irregular node segmented embedded laying techniques, combined with directional trenchless traction technology and three-channel synchronous coherent demodulation, the signal attenuation and positioning error problems of existing fiber optic sensing systems for pipeline network seepage prevention have been solved, achieving high-precision monitoring and closed-loop operation and maintenance throughout the entire life cycle.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- YANGZHOU ZHONGYI TECH CO LTD
- Filing Date
- 2026-04-23
- Publication Date
- 2026-07-24
Smart Images
Figure CN122448447A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of precise positioning technology, specifically to a fiber optic sensing precise positioning system for preventing leakage in pipeline networks. Background Technology
[0002] In the field of urban pipeline network and long-distance oil and gas / water pipeline seepage prevention monitoring, distributed optical fiber sensing technology has become the mainstream technology route. Existing pipeline network seepage prevention optical fiber sensing precision positioning system has multi-dimensional systemic drawbacks and deficiencies, and cannot adapt to the high-precision monitoring needs under complex working conditions.
[0003] Existing technologies mostly employ a single-point axial laying method at the top of the pipeline. For large-diameter pipes, leak signals from the bottom and sides suffer from extremely low effective identification rates after secondary attenuation by the pipe wall and soil. High-risk leak points such as tees, elbows, and valves have natural monitoring blind spots. For trenchless laying schemes in existing aging pipeline networks, it is impossible to balance the coupling efficiency between optical fiber and the pipe wall with construction feasibility, and a precise mapping system between optical fiber path length and pipeline physical coordinates has not been established, leading to inherent mismatch errors in subsequent positioning references. Existing multi-parameter acquisition and processing schemes suffer from inter-channel time synchronization errors, and fixed noise thresholds cannot adapt to dynamic environmental conditions. Changes and long-term performance drift of optical fibers mean that weak signals from micro-leakage near the noise floor are easily submerged, making it impossible to effectively extract features and accurately screen suspected signals. Existing positioning algorithms are all built using linear propagation models of single-point signal sources, which cannot accurately separate aliased signals from multiple leaks or micro-leakages at close range. Due to feature distortion, a large number of spurious peaks are generated, and the serial process of signal splitting and positioning calculation is prone to error accumulation, resulting in significant positioning deviations at irregular nodes. At the same time, existing solutions lack quantitative assessment of positioning errors and a closed-loop operation and maintenance system throughout the entire life cycle, making them unsuitable for engineering-level handling requirements and lacking long-term operational stability.
[0004] Therefore, there is a need to provide a fiber optic sensing precision positioning system for pipeline network leakage prevention. Summary of the Invention
[0005] The purpose of this invention is to provide a fiber optic sensing precision positioning system for pipeline network leak prevention. To solve the above-mentioned problems in the prior art, this invention achieves this through the following technical solution:
[0006] The first part, an embodiment of the present invention, provides a fiber optic sensing precision positioning system for pipeline network leak prevention, specifically including the following modules:
[0007] Adaptive coding module: It adopts a composite process of equal lead spiral laying and irregular node segmented embedded laying, combined with directional trenchless traction technology to adapt to old pipeline networks, and simultaneously constructs a full-domain spatial coding system that maps optical fiber path, spatial position and pipeline physical coordinates to provide a unified spatial reference.
[0008] Screening and storage module: Combining the global spatial coding system, adopting a three-channel synchronous coherent demodulation architecture, dynamically adapting the acquisition frequency and preamplification factor, constructing a dual-dimensional dynamic baseline of environmental noise and fiber performance, and completing the preliminary screening and spatial coding binding storage of suspected leaked signals;
[0009] Decomposition and compensation module: Combining the suspected leakage signal bound by spatial coding, and using the physical coordinates of the pipeline as a hard constraint, it completes the three-dimensional coordinate calculation and the deviation compensation of irregular nodes while performing non-overlapping decomposition of time-domain waveforms and frequency-domain feature clustering verification.
[0010] The positioning and determination module combines the three-dimensional coordinate calculation results, quantifies the total positioning error and precise excavation boundary through the full-dimensional error formula, and completes the determination of leakage level and treatment priority by combining the multi-physical field characteristics of the pipeline network, and simultaneously constructs a closed loop for the full life cycle operation and maintenance of the pipeline network.
[0011] The second part, an embodiment of the present invention, provides a method for precise positioning of pipeline network leak prevention using fiber optic sensing, specifically including the following steps:
[0012] Step 1: Adopt a composite process of equal lead spiral laying and irregular node segmented embedded laying, combined with directional trenchless traction technology to adapt to old pipeline networks, and simultaneously construct a global spatial coding system that maps optical fiber path length, spatial position and pipeline physical coordinates to provide a unified spatial reference.
[0013] Step 2: Combining the global spatial coding system, a three-channel synchronous coherent demodulation architecture is adopted to dynamically adapt the acquisition frequency and preamplification factor, construct a two-dimensional dynamic baseline of environmental noise and fiber performance, and complete the preliminary screening and spatial coding binding storage of suspected leakage signals.
[0014] Step 3: Combining the suspected leakage signal bound by spatial coding, and using the physical coordinates of the pipeline as a hard constraint, while performing non-overlapping decomposition of time-domain waveforms and frequency-domain feature clustering verification, complete the three-dimensional coordinate calculation and compensation for the deviation of irregular nodes.
[0015] Step 4: Combining the three-dimensional coordinate calculation results, the total positioning error and precise excavation boundary are quantified using the full-dimensional error formula. The leakage level and treatment priority are determined by combining the multi-physics field characteristics of the pipeline network, and the entire life cycle operation and maintenance closed loop of the pipeline network is constructed simultaneously.
[0016] The beneficial effects of this invention are:
[0017] 1. Implement full-circumferential adaptive laying and construct a full-domain space-optical path mapping coding system. Employ a pipe diameter-dynamically adapted equal-lead spiral laying process to overcome the problems of signal attenuation and extremely low effective identification rate caused by large-diameter pipe bottom leakage due to existing single-point laying at the top. Segmented embedded laying of irregular nodes reduces monitoring blind spots in high-leakage areas. Adapt directional trenchless technology to existing aging pipe networks. Simultaneously establish optical path and physical coordinate mapping coding to solve the inherent reference error of nonlinear mismatch between optical path and axial distance in spiral laying. Construct a multi-physics field synchronous acquisition and processing and dual-dimensional dynamic baseline self-calibration mechanism. Adopt a three-channel coherent demodulation architecture to eliminate the time misalignment problem of existing multi-parameter acquisition and processing. Construct dual dynamic baselines for environmental noise and fiber performance to overcome the defects of fixed thresholds being unable to adapt to dynamic changes in environmental conditions and long-term aging and drift of optical fibers. Dynamically adapt the acquisition frequency and pre-amplification factor to solve the problem that weak signals of micro-leakage near the noise floor are easily submerged and cannot be effectively extracted.
[0018] 2. An integrated algorithm for multi-point leakage signal decomposition and 3D positioning under spatial constraints is adopted, breaking through the limitations of existing linear models of single-point signal sources. Spatial coding is used as a hard constraint to complete the non-overlapping decomposition of aliased signals, achieving accurate decomposition of near-range multi-point leaks and solving the core pain points of multi-point signal aliasing, feature distortion, and spurious peak interference. Signal decomposition and 3D coordinate calculation are completed simultaneously, eliminating the error accumulation of serial processes. Compensation for irregular node deviations is provided to address the problems of insufficient accuracy in existing 1D positioning and large positioning deviations of irregular nodes. A quantitative assessment of positioning errors and a closed-loop operation and maintenance mechanism throughout the entire lifecycle are adopted. The precise excavation boundary is quantified through a full-dimensional error formula, overcoming the shortcomings of existing positioning results that lack error assessment and cannot guide engineering construction. Combined with the leakage classification judgment of pipeline risk levels, the problems of long-term system accuracy decay and operation and maintenance disconnect are solved. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 This is a schematic diagram of the structure of a fiber optic sensing precision positioning system for preventing leakage in pipelines, provided in Embodiment 1 of the present invention.
[0021] Figure 2 This is a flowchart of the steps of a fiber optic sensing precise positioning method for preventing leakage in pipelines, provided in Embodiment 2 of the present invention. Detailed Implementation
[0022] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art in conjunction with the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.
[0023] Example 1: As Figure 1 As shown in the figure, the fiber optic sensing precision positioning system for pipeline network leakage prevention provided by this embodiment of the invention specifically includes the following modules:
[0024] Adaptive coding module: It adopts a composite process of equal lead spiral laying and irregular node segmented embedded laying, combined with directional trenchless traction technology to adapt to old pipeline networks, and simultaneously constructs a full-domain spatial coding system that maps optical fiber path, spatial position and pipeline physical coordinates to provide a unified spatial reference.
[0025] In a specific embodiment, a full-line route survey of the target pipeline network is conducted to clarify the nominal diameter, burial depth, direction, location and size of irregular nodes, the degree of aging of the pipeline network, and the surrounding geological environment. Irregular nodes include: tees, elbows, valves, and reducers. Laying sections are divided according to pipe diameter, operating conditions, and construction years, with large-diameter sections, densely populated irregular node sections, and old pipeline network sections being the key laying sections. For old pipeline networks, directional trenchless traction equipment is used to open traction holes with a diameter ≤5mm at valve wells on the outer wall of the pipeline network.
[0026] Flexible armored sensing optical fiber is selected to adapt to long-term deformation caused by thermal expansion and contraction of pipeline network and soil settlement, effectively avoiding fiber breakage and sudden bending loss.
[0027] In the pretreatment stage, a high-temperature resistant and corrosion-resistant flexible thermally conductive adhesive is uniformly wrapped on the surface of the optical fiber to enhance the acoustic and thermal coupling efficiency between the optical fiber and the outer wall of the pipeline.
[0028] It should be noted that the flexible armored sensing fiber has a diameter ≤1.2mm, tensile strength ≥1500N, temperature range [-40℃, 80℃], and vibration frequency response range [0.1Hz, 10kHz].
[0029] Large-diameter sections: An equal-lead spiral laying method is adopted, and the spiral spacing is dynamically adapted according to the pipe diameter. The spiral spacing is 0.8 times the nominal diameter of the pipe. During the spiral laying process, the optical fiber is tightly attached to the outer wall of the pipe and spirally wound around it in the circumference. The winding angle is controlled within [30°, 45°] to ensure that the optical fiber continuously covers the entire circumference of the pipe. The leakage signal at the bottom of the pipe can be directly transmitted through the attached optical fiber, avoiding secondary attenuation through the soil and pipe wall.
[0030] The irregular node section adopts a segmented embedded laying process. For nodes with high leakage rates such as tees, elbows, and valves, the optical fiber is cut into segments that perfectly match the node outline. The length of each optical fiber segment is determined according to the node size. The length of each segment in a tee node is 1.5 times the nominal diameter of the node, the length of each segment in an elbow node is 1.2 times the arc length of the elbow, and the length of each segment in a valve node is 1.1 times the circumference of the valve body sealing surface.
[0031] Segmented optical fibers are embedded and bonded to high-leakage locations of the node using flexible adhesive. These high-leakage locations include the junction of the inner and outer walls, the circumferential weld, and the sealing surface, ensuring that there are no blind spots in the node area.
[0032] In old pipeline sections, pre-processed optical fibers are introduced from the valve well traction hole using directional trenchless traction equipment. They are then laid along the outer wall of the pipeline using a spiral method that matches the pipe diameter. The spiral spacing is 0.8 times the nominal diameter of the pipe. During the traction process, the fit between the optical fiber and the pipe wall is controlled by a guide device. The entire process requires no road excavation and no pipeline shutdown.
[0033] After the fiber optic cable is laid, a high-density polyethylene flexible protective sleeve is used to completely wrap the fiber optic cable to prevent damage caused by soil friction and acid / alkali corrosion.
[0034] For sections with conventional pipe diameters, a simplified spiral laying method is adopted, and the spiral spacing is still dynamically adjusted according to the above formula;
[0035] A comprehensive spatial coding system is constructed. After the entire optical fiber is laid, signal acquisition, processing and demodulation modules are connected to both ends of the optical fiber to form a closed sensing loop. At the same time, a unique mapping code is constructed for the entire optical fiber path. The coding rules are as follows: the code includes: laying section number, spiral turn number, circumferential position number and node feature number. Each code corresponds to four sets of parameters: optical fiber path length, duct axial distance, circumferential angle and geographic coordinates. A mapping database of optical path-space-physical coordinates is established.
[0036] Screening and storage module: Combining the global spatial coding system, adopting a three-channel synchronous coherent demodulation architecture, dynamically adapting the acquisition frequency and preamplification factor, constructing a dual-dimensional dynamic baseline of environmental noise and fiber performance, and completing the preliminary screening and spatial coding binding storage of suspected leaked signals;
[0037] In a specific embodiment, a three-channel high-precision synchronous coherent demodulation architecture is adopted. The three acquisition and processing channels correspond to vibration signals, temperature signals, and strain signals, respectively. The time synchronization accuracy between channels is ≤100ns, which completely eliminates the time misalignment problem of multi-parameter signals.
[0038] The sampling frequency is dynamically adjusted based on the spiral laying parameters of the adaptation coding module and the type of pipeline medium to determine the value of the leakage signal strength coefficient. Using this determined leakage signal strength coefficient as the core basis, the spiral laying parameters of the corresponding pipeline section in the adaptation coding module are synchronously matched to complete the calculation and analysis of the target sampling frequency. The leakage signal strength coefficient ranges from [0.1, 0.5], and is determined based on the type of pipeline medium: liquid pipeline network. =0.2, oil and gas mixed transportation pipeline network =0.5, when the helix pitch is less than 200mm Adjust to 0.6;
[0039] The preamplification factor of the acquired and processed signal is dynamically adjusted based on the real-time signal-to-noise ratio (SNR). The SNR of the currently acquired signal is calculated in real time, and the real-time SNR value is obtained. Based on the real-time SNR and combined with a preset signal SNR coefficient, a coupled calculation and analysis are performed to obtain the preamplification factor. It combines historical pipeline operation data and signal noise characteristics for advance preset, and can also be dynamically fine-tuned according to changes in the real-time environmental noise baseline to ensure that the amplification factor matches the signal operating conditions, avoid the weak signal of micro-leakage being submerged by noise during the amplification process, and prevent strong signal saturation distortion.
[0040] After the calculation is completed, it is sent to the preamplifier of the corresponding acquisition channel in real time. The amplification factor of the three channels can be adjusted independently according to the signal-to-noise ratio of their respective signals.
[0041] By using the laid flexible armored sensing optical fiber and the spatial coding system of the adapted coding module, vibration signals, temperature signals and strain signals of each coding point along the entire pipeline are collected synchronously. The signal data of each collection point is bound and stored with the corresponding spatial code to ensure that each signal segment can be accurately traced to the specific physical location of the pipeline. During the collection process, the optical path loss of the entire optical fiber is scanned synchronously, and the optical fiber transmission loss value of each coding point is recorded.
[0042] During the acquisition and processing, full-element dynamic baseline self-calibration is performed, and a two-dimensional dynamic baseline is constructed simultaneously to achieve dual compensation for environmental interference and fiber performance drift.
[0043] Environmental noise signals under leak-free steady-state operation of the pipeline network were continuously collected and processed. Initial calibration involved 30 minutes of continuous data acquisition, with one set of global data collected every 1 minute. During operation, the baseline data was automatically updated every 24 hours to construct a dynamic baseline for environmental noise. The initial environmental noise baseline under leak-free steady-state operation of the pipeline network was obtained. Using this initial environmental noise baseline as a benchmark, and combining the environmental variation coefficient and the system's cumulative operating time, the dynamic baseline of environmental noise at the corresponding calculation time was calculated and analyzed, yielding the dynamic baseline of environmental noise at time t. The environmental change coefficient ranges from [0.001 to 0.005] and is adjusted in real time according to ambient temperature, humidity, and surrounding vibration conditions.
[0044] By combining synchronously scanned fiber transmission loss data, a dynamic baseline for fiber loss is constructed to compensate for signal baseline drift caused by fiber aging, bending loss, and splicing loss. The measured average initial fiber loss reference value for the entire line after fiber laying is obtained. Based on this initial fiber loss reference value, and combined with the fiber loss drift coefficient and the system's cumulative operating time, the fiber loss compensation coefficient at the corresponding calculation time is calculated and analyzed to obtain the fiber loss compensation coefficient at time t. The initial fiber loss reference value is the average loss value measured along the entire line after the laying is completed. The fiber loss drift coefficient ranges from [0.0005, 0.002] and is adjusted according to the loss change rate of the fiber in real time scanning.
[0045] A two-dimensional dynamic baseline for fiber performance is constructed by combining the obtained dynamic baselines for environmental noise and fiber loss.
[0046] After the collected multi-physics field signals were calibrated by the dual-dimensional dynamic baseline of fiber performance, they were compared with the dynamic baseline of environmental noise. Signal segments with a signal intensity greater than 1.2 times the dynamic baseline of environmental noise after calibration were selected as suspected leakage signals, and steady-state environmental interference signals were initially ruled out.
[0047] Record the acquisition time, corresponding spatial code, and signal amplitude and characteristics in three dimensions of suspected leakage signals; for signals with signal strength below the threshold, they are identified as environmental interference signals and directly rejected.
[0048] Decomposition and compensation module: Combining the suspected leakage signal bound by spatial coding, and using the physical coordinates of the pipeline as a hard constraint, it completes the three-dimensional coordinate calculation and the deviation compensation of irregular nodes while performing non-overlapping decomposition of time-domain waveforms and frequency-domain feature clustering verification.
[0049] In a specific embodiment, the suspected leakage signals screened in the screening and storage module are matched with the optical path-space-physical coordinate mapping database constructed by the adaptation coding module according to their bound spatial codes to determine the preliminary range of spatial coordinates for each suspected signal.
[0050] For suspected signals with adjacent spatial codes, i.e., the axial distance between pipes is less than the preset proximity base value, they are judged as suspected multi-point leakage superposition signals and enter the integrated solution process; for suspected signals with non-adjacent spatial codes, single-point feature verification is performed separately to avoid misjudgment.
[0051] For suspected multi-point leakage aliasing signals, the time-domain waveform is decomposed without overlap using the physical location of the pipeline corresponding to the spatial code as a hard constraint. The total time-domain waveform data that is identified as a suspected multi-point leakage aliasing signal is retrieved from the database of the screening and storage module.
[0052] The collected aliased time-domain total signal is the decomposition object. First, the number of leakage points in the aliased signal is determined. The minimum number of leakage points is 2. The physical location of the pipeline corresponding to the spatial code is used as a hard constraint. The aliased time-domain total signal is decomposed into the superposition result of the time-domain signals of the corresponding number of independent leakage points. At the same time, the residual error after decomposition is calculated. The maximum value of the residual error is constrained to be less than or equal to 0.05 to ensure the decomposition accuracy.
[0053] During the decomposition process, the time window of the time domain waveform of each signal is limited according to the axial spacing of adjacent spatial codes. At the same time, the arrival time difference of signals from adjacent leak points is constrained by combining the propagation velocity of the pipe acoustic vibration. This avoids waveform overlap and signal interference distortion during decomposition, and the aliased total time domain signal is obtained by analysis.
[0054] During the decomposition process, the time window of the time domain waveform of each aliased total time domain signal is limited according to the axial spacing of adjacent spatial codes. At the same time, the time difference of signals from adjacent leak points is constrained by combining the propagation velocity of acoustic vibration in the pipeline, so as to avoid waveform overlap and signal interference distortion during the decomposition process.
[0055] Fourier frequency domain transformation is performed on each decomposed aliased time-domain signal. The frequency domain feature parameters of each signal segment are extracted and standardized. The frequency domain feature parameters include: characteristic frequency, frequency amplitude, and frequency bandwidth. An unsupervised clustering method is used to classify the frequency domain features of different signal segments. Fourier frequency domain transformation is performed on each decomposed independent time-domain signal segment to convert the time-domain signal into a frequency-domain signal. The frequency domain feature parameters of each signal segment are extracted and standardized. The core parameters include characteristic frequency, frequency amplitude, and frequency bandwidth.
[0056] For two signal segments to be compared, their characteristic frequencies and frequency amplitudes are obtained respectively. Based on the difference in characteristic frequencies and frequency amplitudes of the two signals, the frequency domain characteristic distance between the two signal segments is calculated.
[0057] Analysis yielded the frequency domain characteristic distance between the two signal segments. , Let m be the characteristic frequency of the m-th signal segment. Let n be the characteristic frequency of the nth signal segment. Let m be the frequency amplitude of the signal segment. The frequency amplitude of the nth signal segment;
[0058] When the frequency domain feature distance is greater than When the frequency domain characteristic distance is less than or equal to the effective signal of two independent leakage points, it is considered a valid signal. When the signal is identified as a repeating signal or a spurious peak signal from the same leak point, it is initially eliminated.
[0059] For the clustered valid signals, multi-physics field correlation verification is performed by combining the temperature and strain signals synchronously collected in the screening and storage module. For the clustered valid signals, the measured temperature and strain signals synchronously collected at the same time stamp corresponding to the spatial coding point of the signal are retrieved.
[0060] The value of the medium correlation coefficient is determined, with a range of [1.1, 1.3], based on the type of medium transported in the pipeline network;
[0061] Set a dual-constraint verification range: the measured temperature signal must fall within the range of "pipeline steady-state operating temperature ± medium correlation coefficient × theoretical temperature change caused by leakage", and the measured strain signal must fall within the range of "pipeline steady-state operating strain ± medium correlation coefficient × theoretical strain change caused by leakage";
[0062] If two measured signals simultaneously satisfy the above two interval constraints, they are determined to be real leakage signals and retained; if either signal does not satisfy the constraint conditions, it is determined to be a false peak signal and discarded.
[0063] It should be noted that the measured temperature and strain signals are retrieved from the three-channel synchronous acquisition database, using the corresponding spatially coded points and the same timestamp for the measured temperature and strain data. During the initial system calibration phase, the steady-state operating temperature and strain of the pipeline network are calculated by continuously collecting temperature and strain data from all points across the entire network for 30 minutes under leak-free steady-state operation, averaging the data, and using this average as the baseline parameters entered into the system. The theoretical temperature and strain changes caused by leakage are calculated based on the pipeline material, the type of transported medium, and the pipeline operating pressure, using fluid mechanics and materials mechanics theories combined with on-site leak calibration tests, and are pre-entered into the system database.
[0064] For the verified micro-leakage signal, i.e., signal strength ≤ Feature enhancement processing is performed, and a threshold for judging micro-leakage signals is set. Real leakage signals with signal strength less than or equal to the threshold are judged as micro-leakage signals and included in the enhancement processing range. The value of the feature enhancement coefficient is determined, with a value range of [0.3, 0.5]. The lower the signal strength, the larger the value of the feature enhancement coefficient, which follows an inverse adaptation rule. Based on the original time-domain signal of the micro-leakage signal, combined with the corresponding assigned feature enhancement coefficient, the enhanced effective micro-leakage signal is calculated and analyzed, and the enhanced time-domain signal is output, thus improving the micro-leakage signal strength to the accurate solution range.
[0065] For each valid leakage signal after verification, the three-dimensional coordinates of axial distance, circumferential angle and burial depth are calculated simultaneously in combination with its bound spatial code. At the same time, the positioning deviation compensation of irregular nodes is completed, so as to realize the simultaneous completion of disassembly and positioning.
[0066] Specifically, axial distance calculation is performed to obtain the initial axial distance of the laying section where the leak point is located, which is used as the calculation benchmark; the number of spiral turns where the leak point is located is multiplied by the spiral spacing of the corresponding section to calculate the cumulative spiral axial distance; the cumulative spiral axial distance is added to the axial offset distance of the leak point within the current spiral turn, and then the initial axial distance of the section is superimposed to obtain the axial distance of the leak point.
[0067] To calculate the circumferential position, the circumferential position number is multiplied by the angular offset corresponding to a single circumferential code to obtain the circumferential angle of the leak point. ,in, Number the circumferential position within the spiral turn where the leak point is located. The number of circumferential codes per turn of the spiral. This is the angular offset corresponding to the circumferential encoding;
[0068] The burial depth coordinates are calculated to obtain the average burial depth of the corresponding pipe top as the calculation benchmark. The sum of the pipe radius and the fiber optic laying depth offset is calculated, and the maximum value of this value is constrained to be less than or equal to 0.2m. Combined with the circumferential angle of the leak point, the burial depth correction value corresponding to the sum of the pipe radius and the offset is calculated. The actual burial depth of the leak point is obtained by adding the burial depth correction value to the average burial depth of the pipe top.
[0069] For leak points at irregular joints such as tees, elbows, and valves, a deviation compensation formula is used to calibrate the three-dimensional coordinates. For leak points at irregular joints, the length deviation of the fiber optic cable at the joint, the circumferential angle of the leak point, the inherent deviation coefficient of the joint, and the nominal diameter of the corresponding pipe are first obtained. The axial distance deviation compensation amount is then analyzed. Compensation amount for circumferential angle deviation The axial distance deviation compensation is superimposed on the original axial distance calculation result, and the circumferential angle deviation compensation is superimposed on the original circumferential angle calculation result. Combined with the burial depth coordinates, the final output is the accurate three-dimensional coordinates of the leakage point at the irregular node after calibration.
[0070] The spatial validity of the three-dimensional coordinates of all leak points after calculation is verified.
[0071] Obtain the squared difference between the axial distances of the m-th and n-th leakage points and the squared difference between their burial depths. Calculate the arithmetic square root of the sum of the two squared differences, and analyze to obtain the spatial linear distance between the m-th and n-th leakage points. ;
[0072] When the spatial straight-line distance between the m-th and n-th leak points is ≥0.5, they are determined to be two independent leak points, and the location result is valid; when the spatial straight-line distance between the m-th and n-th leak points is <0.5, they are determined to be duplicate locations of the same leak point, and the location result with the higher signal strength is retained to avoid duplicate alarms and false judgments.
[0073] Location determination module: Combining the three-dimensional coordinate calculation results, the total positioning error and precise excavation boundary are quantified through the full-dimensional error formula. The leakage level and treatment priority are determined by combining the multi-physical field characteristics of the pipeline network, and the entire life cycle operation and maintenance closed loop of the pipeline network is constructed simultaneously.
[0074] In a specific embodiment, the positioning results are evaluated by full-dimensional error quantification in conjunction with the solution process of the decomposition compensation module, and the total positioning error of each leakage point and the excavation boundary are calculated.
[0075] Four core parameters were obtained: maximum axial positioning error, maximum circumferential positioning error, corresponding nominal pipe diameter, and maximum burial depth positioning error. Hard constraints were set: maximum axial positioning error ≤ 0.3m, maximum circumferential positioning error ≤ 5°, and maximum burial depth positioning error ≤ 0.2m. The maximum circumferential positioning error was converted into the arc length error of the pipe surface by multiplying the maximum circumferential positioning angle error by the circumference length corresponding to the nominal pipe diameter, and then dividing by 360°. Combining the maximum axial positioning error, the converted circumferential arc length error, and the maximum burial depth positioning error, a full-dimensional coupled calculation was completed to analyze and obtain the total error in leak point location. ;
[0076] Based on the total error in locating the leak point and in accordance with pipeline construction specifications, the precise excavation boundary is calculated. The excavation boundary is a circle centered on the three-dimensional coordinates of the leak point, with a radius of [missing information]. The circular area serves as a clear minimum excavation area for maintenance personnel, preventing over-excavation or missed excavation.
[0077] Combining the leakage signal strength, temperature change, and strain change extracted from the decomposition and compensation module, and considering the pipeline network risk level, the leakage level and handling priority are determined. The signal proportions in three dimensions are calculated as follows: First dimension: the effective signal strength at the leak point is divided by the maximum leakage signal strength within the system range to obtain the signal strength proportion; Second dimension: the temperature change caused by the leak is divided by the maximum temperature change within the system range to obtain the temperature change proportion; Third dimension: the strain change caused by the leak is divided by the maximum strain change within the system range to obtain the strain change proportion. The proportion parameters of these three dimensions are then used to perform a coupled calculation, ultimately outputting the leakage level coefficient. The leakage level coefficient ranges from (0,1], with a larger value indicating a more severe leakage.
[0078] Based on the risk level of the pipeline network, the leakage level and response priority are determined:
[0079] when If the leak is identified as a minor leak, the priority for handling ordinary pipeline networks is level three, while the priority for handling high-risk chemical pipeline networks and oil and gas transmission pipeline networks is upgraded to level two.
[0080] when If the leak is classified as a medium-risk leak, the priority for handling ordinary pipelines is Level II, and the priority for handling high-risk pipelines is upgraded to Level I.
[0081] when At that time, it was determined to be a major leak, and all pipeline network treatment was given the highest priority, triggering an emergency warning;
[0082] The complete information of each leak point is standardized and output, including: the three-dimensional coordinates of the leak point, the total positioning error and the precise excavation boundary, the leak level and the treatment priority, the corresponding spatial code, the leak characteristic parameters, the pipeline section and surrounding structures, and is presented simultaneously in the form of text and geographic coordinate map. This informs the operation and maintenance personnel of the specific physical location and operating characteristics of the leak point, and provides complete data support for precise excavation and leak sealing.
[0083] The location results are synchronously transmitted to the pipeline operation and maintenance management system, and standardized treatment plans are automatically generated based on the leakage level and treatment priority. At the same time, a system self-calibration closed loop is constructed.
[0084] Micro-leakage scenario: Generate regular inspection suggestions, clarify the inspection cycle and monitoring focus, and simultaneously include the point in the system's key monitoring scope. Update the signal data of the point every 1 hour to track the development trend of the leak.
[0085] In the event of a leak: generate emergency inspection and on-site leak sealing preparation suggestions, simultaneously push the 3D coordinates of the leak point and the excavation boundary to the mobile terminal of the operation and maintenance personnel, link the surrounding valve well control system, and indicate the range of valves that can be closed;
[0086] In a large-scale leak scenario: the system generates immediate repair suggestions, triggers an emergency audible and visual warning, simultaneously pushes complete information about the leak point to the operation and maintenance and emergency management departments, and coordinates with the pipeline control system to execute emergency valve closure operations to prevent the leak from spreading and secondary disasters from occurring.
[0087] By combining the leak location data after on-site handling and verification, the spatial mapping database, dynamic baseline parameters and solution model are updated to compensate for the performance drift of optical fibers during long-term operation, forming a closed loop throughout the entire life cycle.
[0088] Example 2: Figure 2 As shown in the figure, the present invention provides a method for precise positioning of pipeline network leakage prevention using fiber optic sensing, which specifically includes the following steps:
[0089] Step 1: Adopt a composite process of equal lead spiral laying and irregular node segmented embedded laying, combined with directional trenchless traction technology to adapt to old pipeline networks, and simultaneously construct a global spatial coding system that maps optical fiber path length, spatial position and pipeline physical coordinates to provide a unified spatial reference.
[0090] Step 2: Combining the global spatial coding system, a three-channel synchronous coherent demodulation architecture is adopted to dynamically adapt the acquisition frequency and preamplification factor, construct a two-dimensional dynamic baseline of environmental noise and fiber performance, and complete the preliminary screening and spatial coding binding storage of suspected leakage signals.
[0091] Step 3: Combining the suspected leakage signal bound by spatial coding, and using the physical coordinates of the pipeline as a hard constraint, while performing non-overlapping decomposition of time-domain waveforms and frequency-domain feature clustering verification, complete the three-dimensional coordinate calculation and compensation for the deviation of irregular nodes.
[0092] Step 4: Combining the three-dimensional coordinate calculation results, the total positioning error and precise excavation boundary are quantified using the full-dimensional error formula. The leakage level and treatment priority are determined by combining the multi-physics field characteristics of the pipeline network, and the entire life cycle operation and maintenance closed loop of the pipeline network is constructed simultaneously.
[0093] The above provides a detailed description of one embodiment of the present invention, but the content described is only a preferred embodiment of the present invention and should not be considered as limiting the scope of the present invention. The above formulas are all dimensionless and standardized to obtain numerical calculations. The formulas are derived from software simulations of collected and processed large amounts of data to obtain the most recent real-world results. The preset parameters in the formulas are set by those skilled in the art based on actual conditions and historical experience, and can be adjusted according to actual conditions. The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. All equivalent changes and improvements made in accordance with the scope of the present invention should still fall within the patent coverage of the present invention.
Claims
1. A fiber optic sensing precision positioning system for pipeline network leak prevention, characterized in that, Includes the following modules: Adaptive coding module: It adopts a composite process of equal lead spiral laying and irregular node segmented embedded laying, combined with directional trenchless traction technology to adapt to old pipeline networks, and simultaneously constructs a full-domain spatial coding system that maps optical fiber path, spatial position and pipeline physical coordinates to provide a unified spatial reference. Screening and storage module: Combining the global spatial coding system, adopting a three-channel synchronous coherent demodulation architecture, dynamically adapting the acquisition frequency and preamplification factor, constructing a dual-dimensional dynamic baseline of environmental noise and fiber performance, and completing the preliminary screening and spatial coding binding storage of suspected leaked signals; Decomposition and compensation module: Combining the suspected leakage signal bound by spatial coding, and using the physical coordinates of the pipeline as a hard constraint, it completes the three-dimensional coordinate calculation and the deviation compensation of irregular nodes while performing non-overlapping decomposition of time-domain waveforms and frequency-domain feature clustering verification. The positioning and determination module combines the three-dimensional coordinate calculation results, quantifies the total positioning error and precise excavation boundary through the full-dimensional error formula, and completes the determination of leakage level and treatment priority by combining the multi-physical field characteristics of the pipeline network, and simultaneously constructs a closed loop for the full life cycle operation and maintenance of the pipeline network.
2. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for laying equal-lead spirals is as follows: The entire route of the target pipeline network is surveyed, and the laying sections are divided according to pipe diameter, operating conditions, and construction year. For large-diameter sections, equal-lead spiral laying is adopted, with the spiral spacing set at 0.8 times the nominal pipe diameter. The optical fiber is wrapped circumferentially around the outer wall of the pipe, and the winding angle is controlled within [30°, 45°]. For conventional-diameter sections, simplified spiral laying is adopted, and the spiral spacing is adjusted according to 0.8 times the nominal pipe diameter. In old pipeline sections, pre-treated optical fibers are introduced using directional trenchless traction equipment and laid according to the corresponding spiral spacing. During the traction process, the degree of contact between the optical fiber and the pipe wall is controlled by a guiding device.
3. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for embedding irregularly shaped nodes is as follows: The location and dimensions of pipeline tees, elbows, valves, reducers and other irregular nodes are determined by surveying; the optical fiber is cut into segments that match the node outline, with each segment of the tee node being 1.5 times the nominal diameter of the node, each segment of the elbow node being 1.2 times the arc length of the elbow, and each segment of the valve node being 1.1 times the circumference of the valve body sealing surface. Segmented optical fibers are embedded and bonded to the junction of the inner and outer walls of the node, the circumferential weld, and the sealing surface using flexible adhesive. The optical fibers at the node are spliced using a fusion splicing seamless connection process.
4. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for constructing the global spatial coding system is as follows: After the entire optical fiber is laid, the two ends of the optical fiber are connected to the signal acquisition and demodulation module to form a closed sensing loop; a unique mapping code is constructed for the entire optical fiber path, which is composed of the laying section number, the number of spiral turns, the circumferential position number, and the node feature number; for each code, four sets of parameters are matched: optical fiber path length, duct axial distance, circumferential angle, and geographical coordinates, to establish a mapping database of optical path-space-physical coordinates.
5. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for three-channel synchronous coherent demodulation is as follows: A three-channel high-precision synchronous coherent demodulation architecture is adopted, with three acquisition channels corresponding to vibration, temperature and strain signals respectively, and the time synchronization accuracy between channels is controlled to be ≤100ns. The acquisition frequency is dynamically adjusted based on the spiral laying parameters and the type of pipeline medium; the preamplification factor is dynamically adjusted based on the real-time signal-to-noise ratio. The three types of signals at each coding point along the entire line are collected synchronously through optical fiber. The signal data is bound and stored with the corresponding spatial code. The optical path loss of the entire optical fiber is scanned synchronously, and the transmission loss value of each coding point is recorded.
6. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for obtaining the two-dimensional dynamic baseline of optical fiber performance is as follows: The environmental noise signal of the pipeline network under steady-state operation without leakage was continuously collected. The initial calibration was carried out by continuous collection for 30 minutes, with one set of global data collected every 1 minute. The baseline data was updated every 24 hours during operation to construct a dynamic baseline for environmental noise. Combined with the scanned fiber optic transmission loss data, a dynamic baseline for fiber optic loss was constructed. A two-dimensional dynamic baseline for fiber performance is constructed by combining the obtained dynamic baselines for environmental noise and fiber loss. After the collected multi-physics field signals are calibrated by the dual-dimensional dynamic baseline of fiber performance, they are compared with the dynamic baseline of environmental noise. Segments with a signal intensity greater than 1.2 times the dynamic baseline of environmental noise after calibration are selected as suspected leakage signals, and the corresponding collection information is recorded. Interference signals below the threshold are removed.
7. The fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for non-overlapping decomposition of the time-domain waveform is as follows: The selected suspected leakage signals are matched with the bound spatial code mapping database to determine the preliminary range of the spatial coordinates of each suspected signal. Suspected signals corresponding to adjacent codes with axial spacing of pipes less than the preset proximity base value are identified as suspected multi-point leakage aliasing signals. For aliasing signals, the time-domain waveform is decomposed into non-overlapping components using the physical location of the pipe corresponding to the spatial code as a hard constraint. During the decomposition process, the time window of each signal is limited according to the axial spacing between adjacent codes, and the time difference of signals at adjacent leak points is constrained by the propagation velocity of acoustic vibration in the pipeline.
8. A fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for calculating the three-dimensional coordinates is as follows: The decomposed time-domain signal is subjected to Fourier frequency domain transformation to extract feature frequency, frequency amplitude, and frequency bandwidth parameters. Unsupervised clustering method is used to classify the frequency domain features. The valid signals are verified by multi-physics field correlation. For the verified valid signals, combined with the suspected leakage signals bound by spatial coding, the three-dimensional coordinates of axial distance, circumferential angle and burial depth are calculated simultaneously.
9. A fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for compensating for the deviation of irregular nodes is as follows: For leakage points at irregular joints of tees, elbows, and valves, the three-dimensional coordinates are calibrated, and the compensation amount is substituted into the axial and circumferential calculation results to obtain the calibrated three-dimensional coordinates. The spatial validity of the three-dimensional coordinates of all leak points is verified. The spatial straight-line distance ΔS between two leak points is calculated. If ΔS ≥ 0.5m, it is determined to be an independent leak point. If ΔS < 0.5m, it is determined to be a duplicate location. The result with higher signal strength is retained.
10. A fiber optic sensing precision positioning system for pipeline network leak prevention according to claim 1, characterized in that, The method for closed-loop operation and maintenance throughout the entire lifecycle is as follows: Based on the three-dimensional coordinate calculation results, the total error ΔE in locating the leak point is calculated; combined with the total location error and the pipeline construction specifications, the excavation boundary with the three-dimensional coordinates of the leak point as the center and a radius of (ΔE+0.2)m is calculated; Calculate the leakage level coefficient, classify the leakage level and treatment priority based on the pipeline network risk level; standardize the output of leakage point information and synchronize it to the operation and maintenance management system, generate treatment plans according to the leakage level; and update the mapping database, baseline parameters and solution model based on the on-site treatment verification data to compensate for fiber optic performance drift.