Medium-pressure gas pipe network pressure estimation method and system oriented to pipe network safety

Abstract

The invention relates to the technical field of gas pipe network flow simulation and numerical calculation, and provides a pipe network safety-oriented medium-pressure gas pipe network pressure estimation method, which comprises the following steps of: S1, acquiring topological structure information of a medium-pressure gas pipe network, and finishing initial set values of unmeasured nodes; s2, the representative pressure of each pipe section and the representative pressure of each node are calculated, iterated, updated and recalculated; s3, judging whether the iteration variable quantity of the node representative pressure meets a set convergence condition or not; s4, when the iteration variable quantity does not meet the convergence condition, the step S2 is executed repeatedly; and outputting the node representative pressure as a node pressure estimation result when the iteration variable quantity meets a convergence condition or the current iteration frequency reaches a preset upper threshold value. Layered iterative calculation based on pipe section representative pressure and node representative pressure is introduced, so that the pressure distribution of the medium-pressure gas pipe network can be quickly and stably solved under the condition of lack of complete boundary conditions, and complicated flow and thermal boundary parameters do not need to be depended on.

Description

Technical Field

[0001] This invention relates to the field of gas pipeline flow simulation and numerical calculation technology, and in particular to a method and system for estimating the pressure of medium-pressure gas pipelines for pipeline safety. Background Technology

[0002] In the construction and operation management of urban infrastructure, gas pipeline transmission and distribution systems are crucial infrastructure for ensuring the livelihoods of residents and the operation of industry. In order to make accurate decisions in planning and design, operation scheduling, and anomaly monitoring, engineers often need to conduct numerical simulation calculations on complex urban pipeline networks to obtain the pressure distribution at each node.

[0003] Current methods for calculating gas pipeline network pressure primarily rely on specialized fluid simulation software for modeling, using extensive measured data as boundary conditions for the mathematical model. Obtaining highly accurate pressure distribution results often requires meeting strict numerical constraints and providing complete data input. However, in practical engineering, urban medium-pressure gas pipeline networks are vast, often exceeding hundreds of kilometers in length, and exhibit a grid-like topology, making it difficult to deploy monitoring equipment at all nodes and collect complete data. Traditional numerical methods are more suitable for small, branch-structured pipeline networks; for complex medium-pressure gas pipeline networks, the calculation process is time-consuming and exhibits poor convergence, making it difficult to obtain stable pressure results in a short time. Therefore, engineering practice urgently needs a calculation method that can quickly and accurately estimate the pressure distribution of medium-pressure gas pipeline networks within minutes, even with only partial measurement data, to meet the needs of operational safety assessments and real-time decision-making. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a method and system for estimating the pressure of medium-pressure gas pipeline networks for pipeline safety. With only partial measurement data, it achieves rapid pressure estimation for large-scale grid-like gas pipeline networks through simplified pressure iteration of pipe segments and nodes, improving computational efficiency and engineering adaptability. This provides an efficient and reliable computational basis for the safety assessment and operation scheduling of urban gas pipeline networks. The objective of this invention can be achieved through the following technical solutions: This invention provides a method for estimating the pressure of medium-pressure gas pipelines for pipeline safety, comprising the following steps: Step S1: Obtain the topology information of the medium-pressure gas pipeline network, and set the pressure of the untested node to the average of the gas source outlet pressure and the lowest pressure of the tested node, thus completing the initial setting of the untested node. Step S2: Calculate the representative pressure of each pipe segment using the topology information and the pressure of all nodes in the network. The nodes represent pressure. According to the pressure represented by the node The pressure at the unmeasured nodes is iteratively updated and the representative pressure of each pipe segment is recalculated. The nodes represent pressure. ; Step S3: Determine the pressure represented by the node. Does the iterative change satisfy the set convergence condition? Step S4: When the node represents pressure If the iterative change does not meet the convergence condition, step S2 is repeated; when the iterative change meets the convergence condition or the current iteration count reaches a preset upper limit threshold, the node represents pressure. This will be output as the corresponding node pressure estimation result.

[0005] Further, step S1 includes, Based on the obtained topology information of the medium-pressure gas pipeline network, the gas source node, user node, pipe segment number, pipe segment length, pipe inner diameter, and start and end node connection information of each pipe segment are collected, and a node-pipe segment topology association matrix is ​​established according to the start and end node connection information. Set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure. The gas source outlet pressure, the measured node pressure, and the initial value of the unmeasured node are used together as the initial set value of the total network node pressure.

[0006] Further, step S2 includes, The start and end nodes of each pipe segment are identified based on the topological relationship, and the representative pressure of each pipe segment at each pipe end is calculated. The calculation formula is as follows: ; Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. For each node, retrieve the representative pressure of each pipe segment connected to the node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. .

[0007] Furthermore, the weighting factor The calculation formula is as follows: ; The The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.575.

[0008] Furthermore, the node represents pressure. The calculation formula is as follows: ; Among them, the For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

[0009] Further, step S3 includes, Calculate the absolute value of the difference in node pressure before and after the iterative update for each node, and take the maximum value of the absolute value of the difference as the iterative change. ; The iterative change amount With the preset convergence threshold When comparing, If the convergence condition is met, then the convergence condition is achieved; otherwise, the convergence condition is not achieved.

[0010] Further, step S4 includes, If the iterative change does not meet the convergence condition and the current iteration number is less than the preset upper limit threshold, return to step S2; otherwise, terminate the iterative calculation and directly output the current node representative pressure as the corresponding node pressure estimation result. When the iterative change satisfies the convergence condition, the current node-representing pressure is directly output as the corresponding node pressure estimation result.

[0011] Based on the same inventive concept, this invention provides a medium-pressure gas pipeline network pressure estimation system for pipeline safety, employing the medium-pressure gas pipeline network pressure estimation method described above, including: The initialization module is used to obtain the topology information of the medium-pressure gas pipeline network and set the pressure of the untested nodes to the average of the gas source outlet pressure and the lowest pressure of the tested nodes, thus completing the initial setting of the untested nodes. The iterative update module is used to calculate the representative pressure of each pipe segment and the representative pressure of each node using the topology information and the pressure of all nodes in the network, and to iteratively update the unmeasured node pressure based on the node representative pressure and recalculate the representative pressure of each pipe segment and the representative pressure of each node. The convergence judgment module is used to determine whether the iterative change in pressure represented by the node satisfies the set convergence condition. The iterative control module is used to repeatedly iterate and update when the iterative change of the pressure represented by the node does not meet the convergence condition; and to output the pressure represented by the node as the corresponding node pressure estimation result when the iterative change meets the convergence condition or the current iteration count reaches a preset upper limit threshold.

[0012] Furthermore, the initialization module includes, The topology information acquisition unit is used to acquire gas source nodes, user nodes, pipe segment numbers, pipe segment lengths, pipe inner diameters, and start and end node connection information of each pipe segment based on the acquired topology information of the medium-pressure gas pipeline network, and to establish a node-pipe segment topology association matrix based on the start and end node connection information. The pressure initialization unit is used to set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure; and to use the gas source outlet pressure, the measured node pressure and the initial value of the unmeasured node as the initial set value of the pressure of the entire network nodes.

[0013] Furthermore, the iterative update module includes, The pipe segment representative pressure calculation unit is used to identify the start and end nodes of each pipe segment according to the topological relationship, and to calculate the pipe segment representative pressure at each pipe end. The calculation formula is as follows: ; Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. Nodes represent pressure calculation units, used to retrieve the pressure represented by each pipe segment connected to the node for each node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. The calculation formula is as follows: ; ; Among them, the The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.575; For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

[0014] Compared with the prior art, the present invention has at least one of the following technical advantages: The method of this invention has a simple overall structure, and its computational process has good hierarchical logic and feasibility, which can significantly reduce modeling complexity while maintaining computational stability. By introducing a hierarchical iterative computational framework based on pipe segment representative pressure and node representative pressure, a fast and stable solution for the pressure distribution of medium-pressure gas pipeline networks is achieved even in the absence of complete boundary conditions. This method does not rely on complex flow and thermodynamic boundary parameters and has strong engineering adaptability; at the same time, it is directly compatible with simulation software and engineering design platforms that use the finite volume method, finite difference method, or other discrete solution methods, and has good portability and practicality. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below: Figure 1 This is a flowchart illustrating the steps of the medium-pressure gas pipeline pressure estimation method for pipeline safety according to the present invention. Figure 2 This is a flowchart illustrating the calculation process of the medium-pressure gas pipeline network pressure estimation method for pipeline network safety according to the present invention. Figure 3 This is the gas pipeline network topology in an embodiment of the present invention; Figure 4 This is a comparison table of calculated values ​​and actual collected values ​​in the embodiments of the present invention. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0017] First Embodiment In the construction and operation management of urban infrastructure, gas pipeline transmission and distribution systems are an important component ensuring the livelihood of the people and the operation of industry. In order to achieve more accurate decision support in planning and design, operation scheduling, and anomaly monitoring, engineers often need to conduct numerical simulation calculations on complex urban pipe networks.

[0018] Currently, in engineering practice, specialized fluid dynamics software is mainly used for modeling, specifically for pressure distribution modeling. This type of software is typically based on fluid dynamics equations and steady-state mass conservation equations, requiring numerous preconditions such as pipe flow rate, temperature, gas composition, and roughness, while also relying on multiple boundary conditions (source gas pressure, user gas consumption, temperature changes, flow direction stability, etc.). For example, to simulate a 200km-scale medium-pressure gas pipeline network in a city, pressure data and gas consumption from more than 500 monitoring points are often needed as boundary inputs; otherwise, the model may fail to converge or the calculation error may exceed ±5%.

[0019] However, in practical engineering, it is difficult to obtain sufficient online monitoring data. Taking a typical city as an example, medium-pressure pipe networks are mostly grid-like structures with thousands to tens of thousands of nodes, while the number of nodes equipped with real-time pressure monitoring devices is usually less than 3%. When using existing simulation software, missing boundary conditions must be manually assumed or supplemented by empirical values, leading to unstable calculation results or even failure to converge. In addition, multi-path flow problems are prone to occur in ring-shaped pipe networks, which drastically increases the computational load of traditional adjustment algorithms, and a single solution may take more than several hours.

[0020] Therefore, in the operation of gas pipeline networks, engineers urgently need a method that can obtain relatively accurate pressure distribution within minutes based on only partial measurement data. To meet this need, this invention provides a pressure estimation method for medium-pressure gas pipeline networks oriented towards pipeline safety, applicable to calculation methods for pipeline fluid distribution. It is a reliable calculation method capable of quickly estimating the pressure at various points in the pipeline network even with only estimated pressures from some large end users. According to calculations, using the same mainstream computing server configuration, the calculation time for a medium-pressure gas pipeline network with no more than 20,000 nodes is only about 5% of that using general numerical calculation methods. The accuracy of the calculation results exceeds 90%, still meeting the pressure accuracy requirements for pipeline safety. The method in this embodiment features simplified prerequisite data conditions, high computational efficiency, and strong engineering adaptability, especially suitable for scenarios common in engineering practice where online measurement data is lacking. It provides important computational data support for enhancing pipeline safety assessment. For pipeline networks with complex topologies, the method can significantly reduce reliance on human experience and unnecessary mathematical modeling and debugging time. A scientific and rapid pressure safety assessment method is provided for urban gas pipeline networks operating in the medium-pressure range, and the specific implementation method is as follows: like Figure 1As shown, this invention provides a method for estimating the pressure of a medium-pressure gas pipeline network for pipeline safety, comprising the following steps: Step S1: Obtain the topology information of the medium-pressure gas pipeline network, and set the pressure of the untested node to the average of the gas source outlet pressure and the lowest pressure of the tested node, thus completing the initial setting of the untested node. Step S2: Calculate the representative pressure of each pipe segment using the topology information and the pressure of all nodes in the network. The nodes represent pressure. According to the pressure represented by the node The pressure at the unmeasured nodes is iteratively updated and the representative pressure of each pipe segment is recalculated. The nodes represent pressure. ; Step S3: Determine the pressure represented by the node. Does the iterative change satisfy the set convergence condition? Step S4: When the node represents pressure If the iterative change does not meet the convergence condition, step S2 is repeated; when the iterative change meets the convergence condition or the current iteration count reaches a preset upper limit threshold, the node represents pressure. This will be output as the corresponding node pressure estimation result.

[0021] Further, step S1 includes, Based on the obtained topology information of the medium-pressure gas pipeline network, the gas source node, user node, pipe segment number, pipe segment length, pipe inner diameter, and start and end node connection information of each pipe segment are collected, and a node-pipe segment topology association matrix is ​​established according to the start and end node connection information. Set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure. The gas source outlet pressure, the measured node pressure, and the initial value of the unmeasured node are used together as the initial set value of the total network node pressure.

[0022] Further, step S2 includes, The start and end nodes of each pipe segment are identified based on the topological relationship, and the representative pressure of each pipe segment at each pipe end is calculated. The calculation formula is as follows: ; Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. For each node, retrieve the representative pressure of each pipe segment connected to the node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. .

[0023] Furthermore, the weighting factor The calculation formula is as follows: ; The The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.575.

[0024] Furthermore, the node represents pressure. The calculation formula is as follows: ; Among them, the For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

[0025] Further, step S3 includes, Calculate the absolute value of the difference in node pressure before and after the iterative update for each node, and take the maximum value of the absolute value of the difference as the iterative change. ; The iterative change amount With the preset convergence threshold When comparing, If the convergence condition is met, then the convergence condition is achieved; otherwise, the convergence condition is not achieved.

[0026] Further, step S4 includes, If the iterative change does not meet the convergence condition and the current iteration number is less than the preset upper limit threshold, return to step S2; otherwise, terminate the iterative calculation and directly output the current node representative pressure as the corresponding node pressure estimation result. When the iterative change satisfies the convergence condition, the current node-representing pressure is directly output as the corresponding node pressure estimation result.

[0027] Specifically, to address the issues of the large amount of measurement data required for pressure calculation in existing urban medium-pressure gas pipeline networks, the complexity of modeling and simulation calculations, and the long calculation time, this invention proposes an estimation method that requires only a small amount of basic measurement data and incorporates engineering experience to estimate user usage, thereby quickly estimating the entire pressure distribution of the pipeline network.

[0028] For a pipe segment located between two network nodes, the pressures at both ends of the segment are P1 and P2, respectively; the length of the segment is L, and the inner diameter is Dn; according to this invention, the pressure Pv value representing this segment can be estimated as follows: (1) Among them, pressure and The value ranges from 0.2 to 0.4 MPa.

[0029] Once the representative pressure Pv of each pipe segment is obtained, the pressure at the connection nodes of various types of pipe networks can be estimated using the following methods.

[0030] ① Two-way valves, reducers, and valves A pipe section is connected to each end of a two-way, reducing, and normally open valve, which can be represented as follows: and The two pipe sections have lengths L1 and L2, and an inner diameter of D. n1 and D n2 The representative pressures for both are P. v1 and P v2 The pressure P at the change of diameter or valve. t It can be estimated as follows: (2) in, and for and The length correction factor ranges from 0.5 to 0.575.

[0031] ② Three-way Each of the three ends of the tee is connected to a pipe segment, which can be represented as follows: , and The lengths of the two pipe sections are L1, L2, and L3, respectively, and the inner diameter of the pipe is D. n1 D n2 and D n3 The representative pressures for both are P. v1 and P v2 Then the pressure P at the tee... t It can be estimated as follows: (3) akin, , and for , and The length correction factor ranges from 0.5 to 0.575.

[0032] ③ Sitong Although four-way connections are rare in engineering projects, similar connections can still appear on CAD or GIS maps of pipeline networks. When performing pressure estimations, it's advisable to treat them as four-way connections and use a similar method, which can be written as: (4) akin, , , and for , , and The length correction factor ranges from 0.5 to 0.575.

[0033] With the above basic calculation formulas in place, the pressure of all pipe sections and connection nodes can be estimated using the iterative calculation method proposed in this paper. The calculation process is as follows: Figure 2 As shown.

[0034] Step 1: Initialize all pipe sections of the pipeline network to their normal operating pressure. The average operating pressure of this project can be used for all pipe section pressures P1 and P2, and all node pressures Pt. The initial pressure range is 0.2-0.4 MPa. The pressure at the pipe section pressure terminal P1 or P2 connected to the gas source uses the output pressure of that gas source. The pressure at the pipe section pressure terminal P1 or P2 connected to the user uses the input pressure at that user's location.

[0035] Step 2: Use Equation (1) to calculate the representative pressure Pav for all pipe sections; Step 3: Calculate the pressure Pt at all nodes using equations (2), (3), and (4); Step 4: Assign the pressure Pt of the node to the pressure P1 or P2 of the corresponding end point of the pipe segment connected to the node. Step 5: Check if convergence has occurred. The convergence criterion is the change in node pressure between two adjacent iterations. It's already very small, reaching the convergence tolerance. We can take the absolute value of the maximum pressure change among all nodes. The convergence criteria are as follows: (5) Step 6: If the calculation has converged, output the pressure of all nodes in the pipeline network. If the calculation has not yet converged, return to step 2 and continue the calculation.

[0036] Step 7: If the calculation does not converge, increment the iteration count by 1. If the iteration count exceeds the set value, the calculation is considered a failure and the calculation ends.

[0037] In summary, this method avoids inputting a large amount of prerequisite data: through explicit calculation rules, it achieves pressure distribution calculation and estimation based on the relationship between pipe length and diameter. It only requires estimating the pressure values ​​of the gas source and the user, and then combining this with the known pipe segment structure for convenient calculation. It eliminates the need for parameters that are difficult to measure, such as pipe segment flow rate, temperature, composition, and roughness, and completely solves the difficulties of traditional adjustment calculations caused by the ring structure of pipe networks. This improves the robustness and computational convergence of the overall model. It avoids excessive subdivision of long pipes, achieving structural savings in computational resources and improving simulation efficiency while maintaining simulation accuracy.

[0038] Second Embodiment Based on the same inventive concept, this invention provides a medium-pressure gas pipeline network pressure estimation system for pipeline safety, employing the medium-pressure gas pipeline network pressure estimation method described above, including: The initialization module is used to obtain the topology information of the medium-pressure gas pipeline network and set the pressure of the untested nodes to the average of the gas source outlet pressure and the lowest pressure of the tested nodes, thus completing the initial setting of the untested nodes. The iterative update module is used to calculate the representative pressure of each pipe segment and the representative pressure of each node using the topology information and the pressure of all nodes in the network, and to iteratively update the unmeasured node pressure based on the node representative pressure and recalculate the representative pressure of each pipe segment and the representative pressure of each node. The convergence judgment module is used to determine whether the iterative change in pressure represented by the node satisfies the set convergence condition. The iterative control module is used to repeatedly iterate and update when the iterative change of the pressure represented by the node does not meet the convergence condition; and to output the pressure represented by the node as the corresponding node pressure estimation result when the iterative change meets the convergence condition or the current iteration count reaches a preset upper limit threshold.

[0039] Furthermore, the initialization module includes, The topology information acquisition unit is used to acquire gas source nodes, user nodes, pipe segment numbers, pipe segment lengths, pipe inner diameters, and start and end node connection information of each pipe segment based on the acquired topology information of the medium-pressure gas pipeline network, and to establish a node-pipe segment topology association matrix based on the start and end node connection information. The pressure initialization unit is used to set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure; and to use the gas source outlet pressure, the measured node pressure and the initial value of the unmeasured node as the initial set value of the pressure of the entire network nodes.

[0040] Furthermore, the iterative update module includes, The pipe segment representative pressure calculation unit is used to identify the start and end nodes of each pipe segment according to the topological relationship, and to calculate the pipe segment representative pressure at each pipe end. The calculation formula is as follows: ; Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. Nodes represent pressure calculation units, used to retrieve the pressure represented by each pipe segment connected to the node for each node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. The calculation formula is as follows: ; ; Among them, the The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.575; For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

[0041] Furthermore, in the iterative control module, the iterative change is the maximum absolute value of the difference between the node pressures before and after the iterative update.

[0042] Third Embodiment Typically, domestic city and district-level gas companies generally possess medium-pressure pipeline networks exceeding 200-500 kilometers. Such networks often contain 10,000-20,000 pipes. When the operating pressure range of these networks is 0.2-0.4 MPa, the method recommended in this embodiment significantly simplifies the calculation of pressure distribution across pipe segments. A simplified gas pipeline network example is provided below. Figure 3 The diagram illustrates the calculation results using the method proposed in this embodiment.

[0043] The gas pipeline network topology consists of two gas sources (numbered 1 and 2), three large users (numbered 3, 4, and 5), and 48 pipes (diameter DN200) (numbered 1001-1048). Gas source (1 / 2) supplies gas at 0.352 MPa; the initial estimated pressures for each user (3 / 4 / 5) are 0.311 MPa, 0.292 MPa, and 0.323 MPa, respectively.

[0044] Step 1. Using the initialization method proposed in this embodiment, first initialize the pressure of all pipe sections P1 and P2 to 0.33 (MPa). The initialization pressure is preferably the average of the gas source pressure and the lowest user pressure.

[0045] Step 2. Calculate using the pipe segment and node method proposed in this embodiment. Calculate the representative pressure Pv for 48 pipe segments (numbered 1001-1048) according to formula (1); calculate Pt for 16 tees (numbered 2001-2016) according to formula (2); and calculate Pt for 19 tees (numbered 3001-3019) according to formula (3).

[0046] Step 3. Assign the latest Pt value of the node to the end pressure P1 or P2 of the respective connected pipe segment.

[0047] Step 4. Calculate and statistically analyze the deviations of all 35 nodes (35 in total) between the two iterations. Find the maximum absolute value of the deviation. deviation value Compare. Allowable deviation value. The preferred value is between 0.001 and 0.01.

[0048] Step 5. If the deviation value of the iterative calculation is very small, it is determined that the calculation has converged.

[0049] Step 6. Output all 35 node pressure values.

[0050] Based on the above calculations, the implementation results of this embodiment are compared with the actual measured values. Due to the limited number of instruments at the engineering site, only the pressure of nodes with actual engineering data acquisition values ​​are selected for comparison, such as... Figure 4As shown, the accuracy of the rapid pressure estimation method for medium-pressure gas pipeline networks proposed in this embodiment, which is geared towards pipeline safety, is within ±1%, meeting the engineering estimation requirements.

[0051] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

Claims

1. A method for estimating the pressure of medium-pressure gas pipelines for pipeline safety, characterized in that, Includes the following steps: Step S1: Obtain the topology information of the medium-pressure gas pipeline network, and set the pressure of the untested node to the average of the gas source outlet pressure and the lowest pressure of the tested node, thus completing the initial setting of the untested node. Step S2: Calculate the representative pressure of each pipe segment using the topology information and the pressure of all nodes in the network. The nodes represent pressure. According to the pressure represented by the node The pressure at the unmeasured nodes is iteratively updated and the representative pressure of each pipe segment is recalculated. The nodes represent pressure. ; Step S3: Determine the pressure represented by the node. Does the iterative change satisfy the set convergence condition? Step S4: When the node represents pressure If the iterative change does not meet the convergence condition, step S2 is repeated; when the iterative change meets the convergence condition or the current iteration count reaches a preset upper limit threshold, the node represents pressure. This will be output as the corresponding node pressure estimation result.

2. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 1, characterized in that, Step S1 includes, Based on the obtained topology information of the medium-pressure gas pipeline network, the gas source node, user node, pipe segment number, pipe segment length, pipe inner diameter, and start and end node connection information of each pipe segment are collected, and a node-pipe segment topology association matrix is ​​established according to the start and end node connection information. Set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure. The gas source outlet pressure, the measured node pressure, and the initial value of the unmeasured node are used together as the initial set value of the total network node pressure.

3. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 2, characterized in that, Step S2 includes, The start and end nodes of each pipe segment are identified based on the topological relationship, and the representative pressure of each pipe segment at each pipe end is calculated. The calculation formula is as follows: ； Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. For each node, retrieve the representative pressure of each pipe segment connected to the node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. .

4. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 3, characterized in that, The weighting factor The calculation formula is as follows: ； The The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.

575.

5. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 3, characterized in that, The nodes represent pressure. The calculation formula is as follows: ； Among them, the For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

6. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 3, characterized in that, Step S3 includes, Calculate the absolute value of the difference in node pressure before and after the iterative update for each node, and take the maximum value of the absolute value of the difference as the iterative change. ; The iterative change amount With the preset convergence threshold When comparing, If the convergence condition is met, then the convergence condition is achieved; otherwise, the convergence condition is not achieved.

7. The method for estimating the pressure of a medium-pressure gas pipeline network according to claim 6, characterized in that, Step S4 includes, If the iteration change does not meet the convergence condition and the current iteration number is less than the preset upper limit threshold, return to step S2; Otherwise, terminate the iterative calculation and directly output the current pressure represented by the node as the corresponding node pressure estimation result. When the iterative change satisfies the convergence condition, the current node-representing pressure is directly output as the corresponding node pressure estimation result.

8. A medium-pressure gas pipeline network pressure estimation system for pipeline safety, employing the medium-pressure gas pipeline network pressure estimation method as described in any one of claims 1 to 7, characterized in that, include, The initialization module is used to obtain the topology information of the medium-pressure gas pipeline network and set the pressure of the untested nodes to the average of the gas source outlet pressure and the lowest pressure of the tested nodes, thus completing the initial setting of the untested nodes. The iterative update module is used to calculate the representative pressure of each pipe segment and the representative pressure of each node using the topology information and the pressure of all nodes in the network, and to iteratively update the unmeasured node pressure based on the node representative pressure and recalculate the representative pressure of each pipe segment and the representative pressure of each node. The convergence judgment module is used to determine whether the iterative change in pressure represented by the node satisfies the set convergence condition. The iterative control module is used to repeatedly iterate and update when the iterative change in the pressure represented by the node does not meet the convergence condition. When the iterative change satisfies the convergence condition or the current iteration count reaches a preset upper limit threshold, the pressure represented by the node is output as the corresponding node pressure estimation result.

9. The medium-pressure gas pipeline pressure estimation system according to claim 8, characterized in that, The initialization module includes, The topology information acquisition unit is used to acquire gas source nodes, user nodes, pipe segment numbers, pipe segment lengths, pipe inner diameters, and start and end node connection information of each pipe segment based on the acquired topology information of the medium-pressure gas pipeline network, and to establish a node-pipe segment topology association matrix based on the start and end node connection information. The pressure initialization unit is used to set the pressure of the gas source node to the gas source outlet pressure and set the initial value of the pressure of the unmeasured node to the average value of the gas source outlet pressure and the lowest value of the measured node pressure; and to use the gas source outlet pressure, the measured node pressure and the initial value of the unmeasured node as the initial set value of the pressure of the entire network nodes.

10. The medium-pressure gas pipeline pressure estimation system according to claim 8, characterized in that, The iterative update module includes, The pipe segment representative pressure calculation unit is used to identify the start and end nodes of each pipe segment according to the topological relationship, and to calculate the pipe segment representative pressure at each pipe end. The calculation formula is as follows: ； Among them, the and stated The pressure at both ends of the pipe segment is the node pressure. Nodes represent pressure calculation units, used to retrieve the pressure represented by each pipe segment connected to the node for each node. The weights are determined by a weighting factor composed of the inner diameter of each pipe segment, the length of the pipe segment, and the length correction factor. The pressure represented by each of the aforementioned pipes Perform a weighted calculation to obtain the pressure represented by the node. The calculation formula is as follows: ； ； Among them, the The inner diameter of the i-th pipe segment is... The length of the i-th pipe segment is given by the following formula: The length correction factor for the i-th pipe segment is given, and the... The value range is 0.5 to 0.575; For the pressure represented by the i-th pipe segment connected to the node, the The weighting factor is the weighting factor for the i-th pipe segment.

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