A method for adaptability analysis of natural gas transmission and distribution systems

Abstract

This invention provides a method for adaptability analysis of a natural gas transmission and distribution system. The system has a key node A, and surrounding points B, C, D, E, F, and G connected to the key node A. Absolute pressure sensors are installed at each of these points to measure the absolute pressure of the medium within the pipeline at that point. By sampling and analyzing the pressure values, the flow direction and velocity of the medium within the pipeline segment between the key node and its connected points are obtained. This method solves the technical problems of existing natural gas pipeline systems, such as high cost, numerous construction restrictions, difficulty in providing effective reference for gas supply and allocation, and inability to provide effective data support for new / reconstructed natural gas pipelines. This invention can be widely applied to natural gas pipeline transmission and distribution systems.

Description

Technical Field

[0001] This invention relates to a method for dynamic monitoring of gas pipeline networks, and more particularly to a method for adaptability analysis of natural gas transmission and distribution systems. Background Technology

[0002] Pipeline transmission and distribution systems are a mainstream method for transmitting and distributing urban natural gas. They generally consist of gate stations, gas storage facilities, transmission and distribution networks, pressure regulating facilities, operation and management facilities, and monitoring systems. With rapid societal development and ever-changing urban construction, natural gas pipeline transmission and distribution systems are becoming increasingly complex and large-scale. The need for flow control within the pipeline network is becoming more urgent. However, flow data acquisition facilities cannot be installed on a large scale due to their high cost and stringent implementation requirements. This results in an inability to accurately grasp the flow of natural gas in cities, making it difficult to identify bottlenecks in the pipeline transmission and distribution system. During peak winter gas consumption periods, many areas in cities experience gas outages. Furthermore, the lack of specific and effective data support during the construction, renovation, and expansion of natural gas pipelines inevitably leads to resource waste during the construction process. Summary of the Invention

[0003] This invention addresses the technical problems of existing natural gas transmission pipeline systems, such as high cost, numerous construction restrictions, difficulty in providing effective reference for gas supply allocation, and inability to provide effective data support for new / reconstructed natural gas pipelines, by controlling pipeline flow data through flow data acquisition facilities. It provides a method for adaptability analysis of natural gas transmission and distribution systems, which achieves high-precision, low-cost, and real-time dynamic flow information monitoring through pipeline pressure analysis, thereby providing data support for pipeline network optimization.

[0004] Pressure is the most sensitive variable in fluid measurement, and it is easy to measure and process data. However, in practical applications, two major problems are difficult to solve. First, the absolute error of the pressure sensor will have a significant impact on the calculation of flow rate and velocity. Second, it is necessary to eliminate the influence of gravity pressure gradient in the pipeline network on the system.

[0005] Therefore, the technical solution of the present invention is a method for adaptability analysis of a natural gas transmission and distribution system. The purpose is to eliminate the influence of sensor measurement errors and the gravitational field on the system. The natural gas transmission and distribution system has a key node A, and surrounding points connected to the key node A are B, C, D, E, F, and G. Absolute pressure sensors are installed at each of points A, B, C, D, E, F, and G to measure the absolute pressure of the medium within the pipeline at each corresponding point. The method for adaptability analysis of the natural gas transmission and distribution system specifically includes:

[0006] S1: Let the pressure sampling frequency of the absolute pressure sensor at each point be M Hz, and take the pressure set of the key node and its surrounding distribution points within one period as {A}. i}、{B i}、{C i}、{D i}、{E i}、{F i}、{G i};

[0007] S2: Perform the following processing on the pressure set:

[0008] S2.1: In set {A} i Take a fixed-length data segment from the given data. Suppose that the data segment contains N data points. Perform the following processing on the N data points:

[0009] A r = 2

[0010] Among them: A 均值 = , will A r Iterate until the minimum is reached, then define A at this point. 均值 Let A be the total pressure value at this measuring point at this moment. 全压 ;

[0011] S2.2: Obtain A 全压 Then, in set {B i}、{C i}、{D i}、{E i}、{F i}、{G i Find the match between A and A in this way. 全压 For data segments within the same time period, the total pressure value at each point is calculated using the method in (2.1), and defined as B. 全压 C 全压 D 全压 E 全压 F 全压 G 全压 ;

[0012] Step 3: Define B A =|B 全压 -A 全压 |, successively obtain C A D A E A F A G A ;

[0013] Step 4: After N days, N B's can be obtained. ATake the minimum value and define it as b. Similarly, define and obtain c, d, e, f, and g.

[0014] Step 5: For example, B obtained on day N+1 A C A D A E A F A G A If any value in {b, c, d, e, f, g} is less than the corresponding element value in {b, c, d, e, f, g}, iterate through the element values ​​in {b, c, d, e, f, g} to keep each element in {b, c, d, e, f, g} at its minimum value.

[0015] Preferably, let the pressure values ​​at each measuring point at the same time be A. i B i C i D i E i F i G i Based on the pressure value, the flow direction and velocity of the medium in the pipe section between point A and its adjacent points can be obtained, as follows:

[0016] (1) Within pipe section AB, let h be... f =|B i -A i |-b;as in h f If h > 0, then the medium flows from point A to point B; for example, h f If the value is less than 0, then the medium flows from point B to point A.

[0017] (2) h f By substituting the following simplified hydraulic calculation formula, the real-time flow velocity information for this pipe section can be obtained:

[0018] h f =

[0019] Where: h f Pressure difference, unit: Pa;

[0020] The friction factor is dimensionless.

[0021] L is the length of the pipe section, in meters;

[0022] d is the pipe diameter, in meters (m).

[0023] The density of the medium is expressed in N / m³. 3 ;

[0024] Flow velocity, in m / s;

[0025] g is the acceleration due to gravity, in m / s². 2 ;

[0026] (3) Using the methods described in (1) and (2), the flow direction and velocity of the pipe segments between point A and its surrounding adjacent points are obtained in sequence. The diameter of each pipe segment is optimized according to the flow velocity of the pipe segment, providing data support for pipeline design and pipeline network renovation.

[0027] Preferably, the transmission and distribution system has valve wells at key node A and its surrounding distribution points, and each valve well has a vent pipe, with the absolute pressure sensor installed on the vent pipe.

[0028] Preferably, a pressure sampling cycle is set to 24 hours.

[0029] The beneficial effects of this invention are that by setting pressure sensors at key nodes and surrounding points of the gas pipeline, the absolute pressure value of the medium at each point is monitored. By processing and calculating the pressure values, the flow direction of the medium between the key nodes and surrounding points, as well as the flow velocity of the medium in the pipe section between them, can be obtained. This information can be used to optimize the pipe section diameter or as a reference for pipeline network renovation. This method has low hardware investment costs and accurate and reliable monitoring results, and can be widely promoted in urban gas pipeline network systems. Detailed Implementation

[0030] The present invention will be further described below with reference to embodiments.

[0031] A method for adaptability analysis of a natural gas transmission and distribution system includes the following steps:

[0032] Step 1: Let A be the key node in the transmission and distribution system, and B, C, D, E, F, G, etc. be the surrounding distribution points connected to it. Install absolute pressure sensors at convenient locations (generally, the vent pipe of the valve well can be selected) at each of the points A, B, C, D, E, F, G, etc.

[0033] Step 2: Set the pressure sampling frequency to M Hz, with a period of 24 hours, and obtain the pressure set of each point A, B, C, D, E, F, G... denoted as {A}. i}、{B i}、{C i}、{D i}、{E i}、{F i}、{G i}...;

[0034] Step 3: For {A} i Perform the following processing:

[0035] 1) Given a fixed-length data segment containing N data points, process the N data points as follows:

[0036] A r = 2

[0037] Among them: A 均值 = ;

[0038] A r It reflects not only the average value of signal vibrations, but also the signal fluctuations and dispersion. (A) r Iterating to the minimum means that the fluidity of the medium in the pipe is at its minimum, and the pressure of the medium in the pipe is close to the total pressure. We define A at this point. 均值 Let A be the measurement point at this time. 全压 ;

[0039] 2) Obtain A 全压 Then, in set {B i}、{C i}、{D i}、{E i}、{F i}、{G i Find the matches between A and A in the following order: ... 全压 For data segments within the same time period, calculate the average pressure at each point using the formula in 1), and obtain B respectively. 全压 C 全压 D 全压 E 全压 F 全压 G 全压 ...;

[0040] Step 4: Define B A =|B 全压 -A 全压 |, successively obtain C A D A E A F A G A ...;

[0041] Step 5: After N days, N B's can be obtained. A Take the minimum value and define it as b. Similarly, define and obtain c, d, e, f, g...; for example, the value B obtained on day N+1. A C A D A E A F A G AIf any value in {b, c, d, e, f, g} is less than the corresponding element value in {b, c, d, e, f, g}, iterate through the element values ​​in {b, c, d, e, f, g} to keep each element in {b, c, d, e, f, g} at its minimum value.

[0042] Step 6: Let the pressure values ​​at each measuring point at the same time be A. i B i C i D i E i F i G i ...Based on the pressure value, the flow direction and velocity of the medium in the pipeline between point A and its adjacent points can be obtained. Taking section AB as an example, the method is as follows:

[0043] 1) Let h f =|B i -A i |-b, as in h f If h > 0, then the medium flows from point A to point B; for example, h f If the value is less than 0, then the medium flows from point B to point A.

[0044] 2) h f By substituting the following simplified hydraulic calculation formula, the real-time flow velocity information for each pipe section can be obtained:

[0045] h f =

[0046] Where: h f Pressure difference, unit: Pa;

[0047] The friction factor is dimensionless.

[0048] L is the length of the pipe section, in meters;

[0049] d is the pipe diameter, in meters (m).

[0050] The density of the medium is expressed in N / m³. 3 ;

[0051] Flow velocity, in m / s;

[0052] g is the acceleration due to gravity, in m / s². 2 .

[0053] This application involves installing pressure sensors at key nodes and surrounding points of gas pipelines to monitor the absolute pressure of the medium at each point. By processing and calculating the pressure values, the flow direction of the medium between the key nodes and their surrounding points, as well as the flow velocity of the medium within the pipe sections, can be obtained. This information can be used to optimize the pipe diameter or as a reference for pipeline network renovation. This method has low hardware investment costs and accurate and reliable monitoring results, and can be widely promoted in urban gas pipeline network systems.

[0054] However, the above description is merely a specific embodiment of the present invention and should not be construed as limiting the scope of the present invention. Therefore, any substitution of equivalent components or equivalent changes and modifications made in accordance with the scope of protection of the present invention should still fall within the scope of the claims of the present invention.

Claims

1. A method for adaptability analysis of a natural gas transmission and distribution system, characterized in that, The distribution system has a key node A, and the surrounding distribution points connected to the key node A are B, C, D, E, F, and G. An absolute pressure sensor is installed at each of these points to measure the absolute pressure of the medium within the pipeline at that corresponding point. The distribution system also has valve wells at the key node A and its surrounding distribution points, each valve well having a vent pipe on it, and the absolute pressure sensor is installed on the vent pipe. The specific method for adaptability analysis of the natural gas transmission and distribution system is as follows: S1: Let the pressure sampling frequency of the absolute pressure sensor at each point be... Hertz, taking the pressure set of the key node and its surrounding distribution points within a pressure sampling period as {A} i }、{B i }、{C i }、{D i }、{E i }、{F i }、{G i }; S2: Perform the following processing on the pressure set: S2.1: In the set {A i} to set the length of the data segment, set the data segment has N data, N data as follows: A r = 2 Among them: A 均值 = , will A r Iterate to the minimum, then define A at this point. 均值 Let A be the total pressure value at point A at this moment. 全压 ; S2.2: Obtain A 全压 Then, in set {B i }、{C i }、{D i }、{E i }、{F i }、{G i Find the match between A and A in this way. 全压 For data segments within the same time period, the total pressure value at each point is calculated using the method in S2.1, and defined as B. 全压 C 全压 D 全压 E 全压 F 全压 G 全压 ; S3: Define B A =|B 全压 -A 全压 |, successively obtain C A D A E A F A G A ; S4: After N days, N Bs can be obtained. A Take the minimum value and define it as b. Similarly, define and obtain c, d, e, f, and g to form the set {b, c, d, e, f, g}. S5: B obtained on day N+1 A C A D A E A F A G A If any value in {b, c, d, e, f, g} is less than the corresponding element value in {b, c, d, e, f, g}, iterate through the element values ​​in {b, c, d, e, f, g} to keep each element in {b, c, d, e, f, g} at its minimum value. Let the pressure values ​​at each measuring point at the same time be A. i B i C i D i E i F i G i ,according to The pressure value can be used to obtain the direction and velocity of the medium flow in the pipe section between point A and adjacent points, as follows: (1) Within pipe section AB, let h be... f =|B i -A i |-b;as in h f If h > 0, then the medium flows from point A to point B; for example, h f If the value is less than 0, then the medium flows from point B to point A. (2) h f By substituting the following simplified hydraulic calculation formula, the real-time flow velocity information for this pipe section can be obtained: h f = Where: h f Pressure difference, unit: Pa; The friction factor is dimensionless. L is the length of the pipe section, in meters; d is the pipe diameter, in meters (m). The density of the medium is expressed in N / m³. 3 ; Flow velocity, in m / s; g is the acceleration due to gravity, in m / s². 2 ; (3) Using the methods described in (1) and (2), the flow direction and velocity of the pipe segments between point A and its surrounding adjacent points are obtained in sequence. The diameter of each pipe segment is optimized according to the flow velocity of the pipe segment, providing data support for pipeline design and pipeline network renovation.

2. The method for adaptability analysis of a natural gas transmission and distribution system according to claim 1, characterized in that, Assume a pressure sampling cycle of 24 hours.