A method and system for detecting and quantitatively estimating leaks in a pipeline
By collecting pipeline pressure data to estimate the equivalent flow rate, calculating the deviation index, and analyzing the fluid dynamics equations, the high hardware cost and location difficulties of pipeline leakage detection in existing technologies have been solved, enabling accurate leakage detection and quantitative estimation on long-distance pipelines.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUXI HUA YAN WATER
- Filing Date
- 2026-04-14
- Publication Date
- 2026-07-14
AI Technical Summary
Existing pipeline leakage detection technologies have high hardware costs in long-distance pipeline scenarios, are difficult to identify minor leaks, and cannot accurately locate and quantitatively estimate the amount of leakage, thus failing to meet actual operation and maintenance needs.
By collecting pressure data at the upstream and downstream ends of the pipeline, the equivalent theoretical flow rate is estimated based on a leak-free pipeline model. The deviation index of the pressure-flow relationship is calculated, and the fluid dynamics equations containing leakage terms are analyzed using an optimization algorithm to determine the location of the leakage point and the flow rate.
It enables accurate determination and quantitative estimation of pipeline leakage under limited pressure sensor conditions, reduces hardware costs, and improves the practicality and economy of detection.
Smart Images
Figure CN122384009A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of pipeline leakage detection technology, and in particular to a pipeline leakage detection and quantitative estimation method and system. Background Technology
[0002] Pipeline transportation systems are critical national infrastructure, and their operational safety and economy directly impact resource utilization and production safety. Pipeline leakage can easily lead to resource losses, economic losses, and safety hazards, making it a pressing issue for the industry. Existing leakage detection technologies are mainly divided into two categories: hardware detection and data analysis detection. Among these, software analysis methods based on pressure and flow operating parameters are more widely used.
[0003] Existing leakage detection methods based on pressure and flow parameters typically require the deployment of numerous measuring devices, resulting in high hardware costs and making them difficult to use comprehensively in long-distance pipeline scenarios. Furthermore, they lack the ability to identify minor leaks, which can easily be confused with parameter changes caused by normal operating conditions. In addition, most methods can only determine whether a leak has occurred, but cannot determine the location and amount of the leak, thus failing to meet actual operation and maintenance needs.
[0004] Existing technologies struggle to reliably identify, locate, and calculate pipeline leaks using only a limited number of pressure sensors, thus limiting the practicality and cost-effectiveness of pipeline leak detection. Summary of the Invention
[0005] To address the limitations of existing pipeline leakage detection technologies in achieving accurate leakage identification, location, and quantitative estimation under pressure monitoring alone, and the lack of a structural-level fluid dynamics model and closed-loop inversion mechanism, this invention provides a pipeline leakage detection and quantitative estimation method. The technical solution is as follows: On the one hand, a method for detecting and quantitatively estimating pipeline leakage is provided, the method comprising: Collect upstream pressure data Pu(t) and downstream pressure data Pd(t) of the pipeline; Based on a leak-free pipeline model, the equivalent theoretical flow rate Q is calculated using the real-time pressure difference and pipeline flow resistance parameter R. calc (t); Based on the upstream pressure data Pu(t), the downstream pressure data Pd(t), and the equivalent theoretical flow rate Q calc (t), calculate the deviation index of pressure-flow relationship; Based on the comparison result between the pressure-flow relationship deviation index and the preset threshold, it is determined whether the pipeline has leaked; The pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) is used as input, with the leak location X and the leak flow rate Q as input. lFor the parameters to be determined, an objective function is constructed based on the pipeline fluid dynamics equations that include leakage terms, wherein the pipeline fluid dynamics equations are a quasi-steady-state model established based on mass conservation and Bernoulli's principle and considering friction. The objective function is solved using an optimization algorithm to obtain the location X of the leak point and the leakage flow rate Q. l .
[0006] Optionally, the pipeline flow resistance parameter R is obtained by fitting historical operating data from a leak-free baseline period, and the fitting formula is: Where Pu is the upstream pressure, Pd is the downstream pressure, Q is the flow rate in the pipe under leak-free conditions, L and D are the length and diameter of the horizontal pipe to be measured, respectively, and f is the friction coefficient. For density.
[0007] Optional, calculate the equivalent theoretical flow rate Q. calc The formula for (t) is: .
[0008] Optionally, the pressure-flow relationship deviation index includes the flow deviation ΔQ(t), where the flow deviation ΔQ(t) is the direct flow measurement value Q. real (t) and equivalent theoretical flow rate Q calc The difference between (t), i.e. .
[0009] Optionally, determining whether a pipeline leak has occurred based on a comparison between the pressure-flow deviation index and a preset threshold includes: Determine whether the flow deviation ΔQ(t) is continuously positive and its average value exceeds the first threshold. ; If the conditions are met, then a leak has been identified in the pipeline.
[0010] Optionally, the pressure-flow relationship deviation index includes the correlation coefficient Corr(t) of the upstream and downstream pressure change rates, wherein the correlation coefficient Corr(t) is the correlation value between the upstream pressure change rate dPu / dt and the downstream pressure change rate dPd / dt within the sliding time window.
[0011] Optionally, determining whether a pipeline leak has occurred based on a comparison between the pressure-flow deviation index and a preset threshold includes: Determine whether the correlation coefficient Corr(t) remains below the second threshold. ; If the conditions are met, then it is determined that there is a leak in the pipeline.
[0012] Optionally, the pipeline fluid dynamics equations include: mass conservation equation, ; Piecewise pressure drop equation, , ; Leakage equation, ; Among them, Q u For upstream traffic, Q d For downstream flow, Q l For leakage flow, P l R1 and R2 are the segmented flow resistance coefficients related to the location X of the leak point, k is the leakage coefficient, and P is the pressure at the leak point. env Due to environmental pressures.
[0013] Optionally, the pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) is used as input, with the leak location X and the leak flow rate Q as input. l For the parameters to be determined, an objective function is constructed based on the pipe fluid dynamics equations including leakage terms, including: Based on the pipeline fluid dynamics equations, the upstream model pressure value Pu, determined by the leak point location X and the leak flow rate Q1, is calculated. model (t) and downstream model pressure value Pd model (t); The upstream model pressure value Pu model (t) is compared with the upstream pressure data Pu(t), and the downstream model pressure value Pd is... model (t) is compared with the downstream pressure data Pd(t); The objective function is established based on the principle of minimizing the deviation between each model pressure value and its corresponding pressure data. The expression of the objective function is as follows: .
[0014] On the other hand, a pipeline leakage detection and quantitative estimation system suitable for the above-mentioned method is provided, characterized in that it includes: Pipe (1); Upstream pressure sensor P1 (2) is installed at the upstream end of pipeline (1) to collect upstream pressure data Pu(t); Downstream pressure sensor P2 (3) is installed at the downstream end of pipeline (1) to collect downstream pressure data Pd(t); An optional flow meter F (4) is installed inside the pipe (1) to collect the direct flow measurement value Q. real (t); The data acquisition unit (5) is connected to the upstream pressure sensor P1 (2), the downstream pressure sensor P2 (3), and the optional flow meter F (4) respectively, and is used to collect and transmit pressure data and flow data; The central processing unit (6) is connected to the data acquisition unit (5) and is used to perform equivalent theoretical flow estimation, pressure-flow relationship deviation index calculation, pipeline leakage determination, objective function construction and optimization solution; The alarm and display terminal (7) is connected to the central processing unit (6) and is used to output the leakage detection results, the location of the leakage point X, and the leakage flow rate Q. l It also triggers a leakage alarm.
[0015] This application discloses a method and system for pipeline leakage detection and quantitative estimation, belonging to the field of pipeline leakage detection technology. It aims to solve the problem that existing methods rely on flow measurement devices and are difficult to use for leak location and quantitative estimation. The method includes: collecting pressure data from the upstream and downstream ends of the pipeline; calculating the equivalent theoretical flow rate based on a leak-free pipeline model, using the pressure difference and pipeline flow resistance parameters; calculating the pressure-flow rate deviation index based on the pressure data and the equivalent theoretical flow rate, and determining whether pipeline leakage has occurred based on the comparison result of the deviation index and a preset threshold; after determining that leakage has occurred, using a pressure data sequence composed of pressure data as input, and the leak location and leakage flow rate as parameters to be determined, constructing an objective function based on a set of pipeline fluid dynamics equations including a leakage term, and solving for the leak location and leakage flow rate using an optimization algorithm. This method can be used for pipeline operating status monitoring and the calculation of leak location and leakage flow rate. Attached Figure Description
[0016] Figure 1 The schematic diagram illustrates a pipeline leakage detection and quantitative estimation system according to the present invention; Figure 2 The diagram illustrates the overall process of the pipeline leakage detection and quantitative estimation method of the present invention. Detailed Implementation
[0017] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.
[0018] In this article, "multiple" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship. Example 1
[0019] like Figure 2As shown, a schematic diagram of the overall process of a pipeline leakage detection and quantitative estimation method is presented. This flowchart illustrates the steps and logical sequence of the method of the present invention.
[0020] In this embodiment, in conjunction with the appendix Figure 1 The process of detecting and quantitatively estimating pipeline leakage is explained.
[0021] Step 101: Collect upstream pressure data Pu(t) and downstream pressure data Pd(t) of the pipeline.
[0022] In this embodiment, pressure acquisition devices are installed at the upstream and downstream ends of the pipeline to continuously acquire pressure signals at fixed time intervals, thereby obtaining Pu(t) and Pd(t) that change with time.
[0023] Step 102: Based on the leak-free pipeline model, calculate the equivalent theoretical flow rate Q according to the real-time pressure difference and pipeline flow resistance parameter R. calc (t).
[0024] In this embodiment, a leak-free pipeline steady-state model is used to calculate the equivalent theoretical flow rate Q under the current operating condition based on the real-time upstream and downstream pressure difference and the flow resistance parameter R. calc (t).
[0025] Step 103, based on the upstream pressure data Pu(t), the downstream pressure data Pd(t), and the equivalent theoretical flow rate Q calc (t), calculate the deviation index of pressure-flow relationship.
[0026] In this embodiment, based on pressure data and theoretical flow rate, a deviation index is calculated according to preset rules to characterize the degree of difference between the actual pipeline operating state and the theoretical state without leakage.
[0027] Step 104: Based on the comparison result between the pressure-flow relationship deviation index and the preset threshold, determine whether the pipeline has leaked.
[0028] In this embodiment, the real-time value of the deviation index is compared with a preset threshold, and the presence of leakage in the pipeline is determined according to a preset judgment rule.
[0029] Step 105: Using the pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) as input, and the leak point location X and leakage flow rate Q are used as input. l For the parameters to be determined, an objective function is constructed based on the set of pipe fluid dynamics equations that include leakage terms.
[0030] The pipeline fluid dynamics equations are a quasi-steady-state model based on mass conservation and Bernoulli's principle, taking into account friction.
[0031] In this embodiment, continuously collected pressure data is used as model input, and the leak location X and leakage flow rate Q are used as the model input. l As unknowns to be determined, based on the conservation of mass, Bernoulli's principle and considering pipe friction, a quasi-steady-state fluid dynamics equation set including leakage terms is established, and an objective function is constructed based on this equation set.
[0032] Step 106: Solve the objective function using an optimization algorithm to obtain the location X of the leak point and the leakage flow rate Q. l .
[0033] In this embodiment, the objective function is iteratively solved using a preset optimization algorithm. Within the feasible region, the unknown values that satisfy the objective function's conditions are searched, and the corresponding X and Q are output. l .
[0034] In this embodiment, by sequentially executing pressure data acquisition, theoretical flow rate estimation, pressure-flow rate deviation calculation, leakage determination, and parameter inversion solution based on fluid dynamics equations, leakage detection, location, and quantitative estimation are completed within the same processing flow. Each step forms a continuous calculation link through data sequence transmission, thereby realizing a complete processing flow from pressure input to leakage parameter output. Example 2
[0035] In one possible implementation, the pipe flow resistance parameter R is obtained by fitting historical operating data from a leak-free baseline period, and the fitting formula is: Where Pu is the upstream pressure, Pd is the downstream pressure, Q is the flow rate in the pipe under leak-free conditions, L and D are the length and diameter of the horizontal pipe to be measured, respectively, and f is the friction coefficient. For density.
[0036] Specifically, a baseline period of pipeline operation without leakage was selected, and multiple sets of upstream pressure Pu, downstream pressure Pd, and corresponding flow rate Q data were collected. This data was then analyzed based on the formula Pu - Pd = RQ. 2 The flow resistance parameter R is obtained by fitting the data. The physical meaning of R is related to the pipe length, diameter, friction, and fluid density. The least squares method can be used in the fitting process to reduce parameter errors by using multiple sets of historical data.
[0037] In this embodiment, the pipeline flow resistance parameter R is fitted by selecting historical operating data from a leak-free baseline period, so that the parameter matches the actual physical characteristics of the pipeline under test. This allows the pressure-flow relationship established based on the parameter to reflect the actual operating conditions and provides a consistent parameter basis for subsequent theoretical flow calculations. Example 3
[0038] Furthermore, the equivalent theoretical flow rate Q is calculated. calc The formula for (t) is: .
[0039] In this embodiment, based on the real-time collected Pu(t) and Pd(t) and the fitted R, according to the equivalent theoretical flow rate Q... calc The formula for (t) calculates the equivalent theoretical flow rate time-by-time. Where Pu(t) is the measured pressure at the upstream end at time t, Pd(t) is the measured pressure at the downstream end at time t, R is the overall pipe flow resistance parameter, and Q... calc (t) represents the theoretical flow rate at time t under leak-free conditions.
[0040] In this embodiment, the equivalent theoretical flow rate Q is calculated using the upstream and downstream pressure difference and the flow resistance parameter R. calc (t) enables flow information to be obtained indirectly from pressure data, thereby establishing a correspondence between pressure and flow without the need for direct flow measurement, and providing a unified theoretical reference for subsequent deviation calculation. Example 4
[0041] Furthermore, the pressure-flow relationship deviation index includes the flow deviation ΔQ(t), where ΔQ(t) is the direct flow measurement value Q. real (t) and equivalent theoretical flow rate Q calc The difference between (t), i.e. .
[0042] The pressure-flow deviation index uses the flow deviation ΔQ(t), which is determined by the measured flow rate Q in the pipeline. real (t) minus the equivalent theoretical flow rate Q calc (t) is obtained. Q real (t) Data collected in real time from a flow meter installed on the pipeline, Q calc (t) represents the theoretical flow rate calculated based on the pressure difference.
[0043] Then, determining whether pipeline leakage has occurred based on the comparison result of the pressure-flow deviation index and the preset threshold includes: judging whether the flow deviation ΔQ(t) is continuously positive and the average value exceeds the first threshold. If the condition is met, then it is determined that a leak has occurred in the pipeline.
[0044] In this embodiment, ΔQ(t) is monitored over a continuous time period to determine whether ΔQ(t) remains positive. Simultaneously, the average value of ΔQ(t) over that time period is calculated, and the average value is compared with a first threshold. For comparison, when it is consistently positive and the average value is greater than 100%. At that time, it was determined that the pipeline was leaking.
[0045] In one example, a crude oil pipeline is used for illustration. The pipeline is 10 km long and 0.5 m in diameter. Under normal, leak-free operation, historical operating data shows that the flow deviation ΔQ(t) mainly fluctuates within -2 m. 3 / h to 2m 3 Between / h.
[0046] Based on this, a segment of leak-free operating data was selected as a benchmark sample. Statistical analysis was performed on the average value of ΔQ(t) within a continuous time window, revealing that its mean is close to 0 and its absolute value does not exceed 1.5m. 3 / h. Based on the above statistical results, the first threshold is... Set to 3m 3 / h.
[0047] In actual operation, ΔQ(t) is monitored within a continuous time window (e.g., 10 s). When ΔQ(t) is detected to be continuously positive and the average value within that time window is greater than 3m, the result is considered positive. 3 When the time reaches / h, it is determined that a leak has occurred in the pipeline.
[0048] For example, within a certain detection period, the average value of ΔQ(t) over 15 consecutive seconds is 4.2m. 3 If the value of ΔQ(t) is positive at each time point, then the above judgment condition is met, thus determining that there is leakage in the pipeline during this period.
[0049] In summary, by calculating the difference ΔQ(t) between the measured flow rate Qreal(t) and the equivalent theoretical flow rate Qcalc(t), the difference between the actual operating state and the leak-free theoretical state can be characterized in the form of flow rate, thus transforming the deviation of the pressure-flow relationship into a calculable quantity. Correspondingly, by judging the sign and average value of the flow deviation ΔQ(t) over a continuous time range, leakage judgment is based on time series data, thereby making the judgment process consider both the direction and duration of deviation, forming a judgment method based on continuous data. Example 5
[0050] Furthermore, the pressure-flow relationship deviation index includes the correlation coefficient Corr(t) of the upstream and downstream pressure change rates, which is the correlation value between the upstream pressure change rate dPu / dt and the downstream pressure change rate dPd / dt within the sliding time window.
[0051] In this embodiment, the deviation index of the pressure-flow relationship is the correlation coefficient Corr(t) of the upstream and downstream pressure change rates. dPu / dt is obtained by differencing Pu(t), and dPd / dt is obtained by differencing Pd(t). The correlation coefficient of the two rate change sequences is calculated within a sliding time window of a set length to obtain Corr(t). The sliding window length can be set to 5~30s.
[0052] Then, determining whether pipeline leakage has occurred based on the comparison result of the pressure-flow deviation index and the preset threshold includes: determining whether the correlation coefficient Corr(t) is continuously lower than the second threshold. If the condition is met, then it is determined that a leak has occurred in the pipeline.
[0053] In this embodiment, the correlation coefficient Corr(t) is monitored in real time. When Corr(t) remains below a second threshold for a continuous period of time... At that time, it was determined that the pipeline was leaking.
[0054] In one example, a long-distance oil pipeline is used as an illustration. Under leak-free operation, statistical analysis of the correlation coefficient Corr(t) within the sliding time window using historical operating data shows that the values of Corr(t) are typically distributed between 0.92 and 0.99, indicating a high degree of consistency in the upstream and downstream pressure change rates.
[0055] Based on the above statistical results, the second threshold will be... Set to 0.85.
[0056] In actual operation, Corr(t) is monitored within a continuous time window (e.g., 10 seconds). When Corr(t) is detected to be continuously below 0.85 within a continuous time period, it is determined that a pipeline leak has occurred.
[0057] For example, if the average value of Corr(t) is 0.72 within a certain detection period and Corr(t) is below 0.85 at each time point, then the judgment condition is met, and it is determined that there is leakage in the pipeline during that period.
[0058] In summary, by calculating the correlation coefficient Corr(t) between the upstream pressure change rate dPu / dt and the downstream pressure change rate dPd / dt, the dynamic relationship of pressure signal changes can be used to characterize the pipeline operating status, thereby constructing a pressure-flow relationship deviation index without direct flow measurement. Correspondingly, by comparing the correlation coefficient Corr(t) with a preset threshold over a continuous time range, leakage judgment is based on the consistent changes in the pressure change relationship, thus realizing a judgment method based on dynamic characteristics. Example 6
[0059] Optionally, the pipeline fluid dynamics equations include: mass conservation equation, ; Piecewise pressure drop equation, , ; Leakage equation, ; Among them, Q u For upstream traffic, Q d For downstream flow, Q l For leakage flow, P l R1 and R2 are the segmented flow resistance coefficients related to the location X of the leak point, k is the leakage coefficient, and P is the pressure at the leak point. env Due to environmental pressures.
[0060] In this embodiment, when leakage occurs at a distance X from the upstream location in the pipeline, and the leakage flow rate is Q... l At this point, a quasi-steady-state hydrodynamic equation set is established. The mass conservation equation Q... u =Q d +Q l The upstream flow rate equals the sum of the downstream flow rate and the leakage flow rate; the piecewise pressure drop equation describes the relationship between the pressure loss from upstream to the leak point and from the leak point to downstream and the square of the flow rate; the leakage equation states that the leakage flow rate is proportional to the square root of the difference between the leak point pressure and the ambient pressure. Q u Q represents the flow rate upstream of the leak point. d Q is the downstream flow rate of the leak point. l For leakage flow, P l R is the pressure at the leak point, R1 and R2 are the piecewise flow resistance coefficients that vary with the location X of the leak point, k is the leakage coefficient, and P is the pressure at the leak point. env The external environmental pressure of the pipeline.
[0061] In summary, by combining the mass conservation equation, the piecewise pressure drop equation, and the leakage equation, a set of pipeline fluid dynamics equations containing leakage terms is constructed. This allows the flow distribution relationship and pressure distribution relationship under leakage conditions to be described within the same mathematical framework, thus forming a combined expression that includes the relationship between leakage location, leakage flow rate, and pressure variables. Example 7
[0062] Furthermore, in Embodiment 1, the pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) is used as input, and the leak location X and leakage flow rate Q are used as input. l Step 105, which involves constructing the objective function based on the pipeline fluid dynamics equations including leakage terms for the parameters to be determined, includes the following:
[0063] Step 1051: Based on the pipeline fluid dynamics equations, calculate the upstream model pressure value Pu, which is determined by the leak point location X and the leak flow rate Q1. model (t) and downstream model pressure value Pd model (t); Step 1052, the upstream model pressure value Pu model (t) is compared with the upstream pressure data Pu(t), and the downstream model pressure value Pd is... model (t) is compared with the downstream pressure data Pd(t); Step 1053: Based on the principle of minimizing the deviation between each model pressure value and its corresponding pressure data, the objective function is established. The expression of the objective function is: .
[0064] In this embodiment, the location of the leak point X is compared with the leakage flow rate Q. l Substituting this variable into the fluid dynamics equations, we obtain the corresponding upstream model pressure Pu. model (t) and downstream model pressure Pd model (t). The model pressure and the measured pressures Pu(t) and Pd(t) are compared time-by-time, and the objective function is constructed with the goal of minimizing the sum of squared errors. X and Q are adjusted iteratively. l To approximate the measured pressure using the model, gradient descent, genetic algorithm, or other nonlinear optimization methods are employed to complete the solution.
[0065] In summary, an objective function was established based on minimizing the deviation between the model pressure and the measured pressure, and the location of the leak point X and the leakage flow rate Q were considered together. l As variables to be optimized, the process of determining leakage parameters is transformed into an optimization problem, thereby enabling parameter inversion calculation based on the degree of matching between the model and the data. Example 8
[0066] On the other hand, such as Figure 1 As shown, a pipeline leakage detection and quantitative estimation system applicable to the above method is also provided, comprising: Pipeline (1); upstream pressure sensor P1 (2), located at the upstream end of pipeline (1), used to collect upstream pressure data Pu(t); downstream pressure sensor P2 (3), located at the downstream end of pipeline (1), used to collect downstream pressure data Pd(t); optional flow meter F (4), located inside the pipeline (1), used to collect direct flow measurement value Qreal(t); data acquisition unit (5), connected to the upstream pressure sensor P1 (2), the downstream pressure sensor P2 (3) and the optional flow meter F (4) respectively, used to collect and transmit pressure data and flow data; central processing unit (6), connected to the data acquisition unit (5), used to perform equivalent theoretical flow calculation, pressure-flow relationship deviation index calculation, pipeline leakage judgment and objective function construction and optimization solution; alarm and display terminal (7), connected to the central processing unit (6), used to output leakage detection results, leakage point location X and leakage flow Ql, and to alarm when leakage is detected.
[0067] Combined with appendix Figure 1 The pipeline leakage detection and quantitative estimation system is described below. The upstream pressure sensor P1 (2) and the downstream pressure sensor P2 (3) are used to collect the pressure data Pu(t) and Pd(t) at the upstream and downstream ends of the pipeline (1), respectively. The optional flow meter F (4) is used to collect the direct flow measurement value Q. real (t). The data acquisition unit (5) is used to collect pressure data and flow data and transmit them to the central processing unit (6). The central processing unit (6) processes the received data and completes the equivalent theoretical flow calculation, pressure-flow relationship deviation index calculation, leakage judgment, and parameter inversion solution based on the fluid dynamics equations to obtain the leakage point location X and leakage flow rate Q. l The alarm and display terminal (7) is used to display the calculation results and output alarm information when leakage is detected.
[0068] In this embodiment, through data transmission and processing between the above-mentioned units, the continuous execution of pressure data acquisition, theoretical calculation, deviation analysis, leakage judgment and parameter output is realized, so that the method has a corresponding system implementation structure.
[0069] Those skilled in the art will understand that all or part of the steps of the above embodiments can be implemented by hardware or by a program instructing related hardware. The program can be stored in a computer-readable storage medium, such as a read-only memory, a disk, or an optical disk.
[0070] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.
Claims
1. A method for detecting and quantitatively estimating pipeline leakage, characterized in that, The method includes: Collect upstream pressure data Pu(t) and downstream pressure data Pd(t) of the pipeline; Based on a leak-free pipeline model, the equivalent theoretical flow rate Q is calculated using the real-time pressure difference and pipeline flow resistance parameter R. calc (t); Based on the upstream pressure data Pu(t), the downstream pressure data Pd(t), and the equivalent theoretical flow rate Q calc (t), calculate the deviation index of pressure-flow relationship; Based on the comparison result between the pressure-flow relationship deviation index and the preset threshold, it is determined whether the pipeline has leaked; The pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) is used as input, with the leak location X and the leakage flow rate Q as input. l For the parameters to be determined, an objective function is constructed based on the pipeline fluid dynamics equations that include leakage terms, wherein the pipeline fluid dynamics equations are a quasi-steady-state model established based on mass conservation and Bernoulli's principle and considering friction. The objective function is solved using an optimization algorithm to obtain the location X of the leak point and the leakage flow rate Q. l .
2. The method according to claim 1, characterized in that, The pipeline flow resistance parameter R is obtained by fitting historical operating data from a leak-free baseline period, and the fitting formula is: Where Pu is the upstream pressure, Pd is the downstream pressure, Q is the flow rate in the pipe under leak-free conditions, L and D are the length and diameter of the horizontal pipe to be measured, respectively, and f is the friction coefficient. For density.
3. The method according to claim 2, characterized in that, Calculate the equivalent theoretical flow rate Q calc The formula for (t) is: 。 4. The method according to claim 1, characterized in that, The pressure-flow relationship deviation index includes the flow deviation ΔQ(t), where ΔQ(t) is the direct flow measurement value Q. real (t) and equivalent theoretical flow rate Q calc The difference between (t), i.e. .
5. The method according to claim 4, characterized in that, The step of determining whether a pipeline leak has occurred based on the comparison result between the pressure-flow relationship deviation index and a preset threshold includes: Determine whether the flow deviation ΔQ(t) is continuously positive and its average value exceeds the first threshold. ; If the conditions are met, then it is determined that there is a leak in the pipeline.
6. The method according to claim 1, characterized in that, The pressure-flow relationship deviation index includes the correlation coefficient Corr(t) of the upstream and downstream pressure change rates. The correlation coefficient Corr(t) is the correlation value between the upstream pressure change rate dPu / dt and the downstream pressure change rate dPd / dt within the sliding time window.
7. The method according to claim 6, characterized in that, The step of determining whether a pipeline leak has occurred based on the comparison result between the pressure-flow relationship deviation index and a preset threshold includes: Determine whether the correlation coefficient Corr(t) remains below the second threshold. ; If the conditions are met, then it is determined that there is a leak in the pipeline.
8. The method according to claim 2, characterized in that, The pipeline fluid dynamics equations include: mass conservation equation, ; Piecewise pressure drop equation, , ; Leakage equation, ; Among them, Q u For upstream traffic, Q d For downstream flow, Q l For leakage flow, P l R1 and R2 are the segmented flow resistance coefficients related to the location X of the leak point, k is the leakage coefficient, and P is the pressure at the leak point. env Due to environmental pressures.
9. The method according to claim 8, characterized in that, The pressure data sequence consisting of the upstream pressure data Pu(t) and the downstream pressure data Pd(t) is used as input, with the leak location X and the leak flow rate Q as input. l For the parameters to be determined, an objective function is constructed based on the pipe fluid dynamics equations including leakage terms, including: Based on the pipeline fluid dynamics equations, the upstream model pressure value Pu, determined by the leak point location X and the leak flow rate Q1, is calculated. model (t) and downstream model pressure value Pd model (t); The upstream model pressure value Pu model (t) is compared with the upstream pressure data Pu(t), and the downstream model pressure value Pd is... model (t) is compared with the downstream pressure data Pd(t); The objective function is established based on the principle of minimizing the deviation between each model pressure value and its corresponding pressure data. The expression of the objective function is as follows: 。 10. A pipeline leakage detection and quantitative estimation system applicable to any one of claims 1 to 9, characterized in that, include: Pipe (1); Upstream pressure sensor P1 (2) is installed at the upstream end of pipeline (1) to collect upstream pressure data Pu(t); Downstream pressure sensor P2 (3) is installed at the downstream end of pipeline (1) to collect downstream pressure data Pd(t); An optional flow meter F (4) is installed inside the pipe (1) to collect the direct flow measurement value Q. real (t); The data acquisition unit (5) is connected to the upstream pressure sensor P1 (2), the downstream pressure sensor P2 (3), and the optional flow meter F (4) respectively, and is used to collect and transmit pressure data and flow data; The central processing unit (6) is connected to the data acquisition unit (5) and is used to perform equivalent theoretical flow estimation, pressure-flow relationship deviation index calculation, pipeline leakage determination, objective function construction and optimization solution; The alarm and display terminal (7) is connected to the central processing unit (6) and is used to output the leakage detection results, the location of the leakage point X, and the leakage flow rate Q. l It also triggers a leakage alarm.