A method for selecting a site for transforming a remote emergency shut-off valve of a town gas pipeline network in service

Abstract

The application discloses a kind of in-service town gas pipe network remote emergency cut-off valve reconstruction site selection method, it is related to gas pipe network safety control technical field, the method includes: constructing three-dimensional evaluation system including pipe network connectivity index, valve flow rate index, the three-dimensional evaluation system of influencing user number index is modified importance index weight;Based on three-dimensional evaluation system and the importance index weight of correction, build comprehensive evaluation model, identify several key valves based on comprehensive evaluation model;Based on the severity of the consequences of leakage and the timeliness of rescue of key valve, build remote emergency cut-off valve reconstruction priority evaluation model, determine the remote emergency cut-off valve reconstruction site of in-service town gas pipe network based on remote emergency cut-off valve reconstruction priority evaluation model, solve the valve reconstruction method of town gas pipe network that has been put into operation cannot reasonably select reconstruction site, leading to the problem of high reconstruction cost and low gas safety.

Description

Technical Field

[0001] This invention relates to the field of gas pipeline safety control technology, specifically to a method for selecting locations for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network. Background Technology

[0002] Urban gas pipeline networks are the core of urban lifeline projects, bearing the crucial responsibility of safely and stably delivering gas to various users. Currently, most pipelines are laid in densely populated areas. If a large-scale leak occurs and cannot be controlled in time, it will not only disrupt the safe and stable operation of the gas supply network but may also cause casualties.

[0003] Currently, emergency shut-off after a pipeline leak mainly relies on manual on-site valve operation. However, this method suffers from long response delays, low efficiency, and direct safety risks to operators, making it difficult to meet the rapid emergency response requirements of modern cities. Therefore, deploying emergency shut-off valves with remote control capabilities has become an industry consensus. This technology can quickly and remotely shut off valves in the early stages of a leak, effectively curbing the escalation of the situation and significantly improving the safety and controllability of the pipeline network.

[0004] For urban gas pipeline networks already in operation, the deployment of remote emergency shut-off valves is usually achieved by automating existing conventional valves. However, due to the large number of valves in the pipeline network, a comprehensive upgrade is not feasible from a cost and efficiency perspective. Therefore, scientifically selecting the valves that have the most critical impact on pipeline safety and operation for priority upgrade has become a core issue in engineering practice. Summary of the Invention

[0005] To address the problem of high modification costs and low gas safety caused by the inability to rationally select modification sites for valve retrofitting in existing urban gas pipeline networks, this method provides a site selection method for remote emergency shut-off valve retrofitting in in-service urban gas pipeline networks. The method includes:

[0006] A three-dimensional evaluation system is constructed, which includes indicators of pipeline connectivity, valve flow rate, and number of affected users. The weights of the importance indicators in the three-dimensional evaluation system are then adjusted.

[0007] A comprehensive evaluation model is constructed based on the three-dimensional evaluation system and the modified importance index weights, and several key valves are identified based on the comprehensive evaluation model.

[0008] Based on the severity of the leakage consequences and the timeliness of emergency response of the key valves, a priority evaluation model for the modification of remote emergency shut-off valves is constructed, and the modification points of remote emergency shut-off valves in the urban gas pipeline network in service are determined based on the remote emergency shut-off valve modification priority evaluation model.

[0009] This method establishes three valve importance indices by comprehensively considering the topological attributes of the gas pipeline network, the gas transmission and distribution attributes, and the impact on gas supply after failure. It also modifies the subjective weighting of these indices to ensure the rationality of the weight allocation, thereby constructing a comprehensive evaluation model to accurately identify critical valves in the operating urban gas pipeline network. Based on the severity of the consequences of critical valve leaks and the timeliness of emergency response, a priority evaluation model for remote emergency shut-off valve retrofitting is constructed. Retrofitting is evaluated sequentially based on priority ranking, fully considering the actual application scenarios of remote emergency shut-off valves, reducing retrofitting costs, improving the rationality of retrofitting site selection, and further strengthening the safe operation guarantee of the operating gas pipeline network.

[0010] Furthermore, the first calculation formula for obtaining the pipeline connectivity index is:

[0011] ;

[0012] ;

[0013] in, Indicates conventional valves Pipeline connectivity indicators This indicates the pipeline connectivity efficiency when the gas pipeline network is supplying gas normally. Indicates the number of gas source points. Indicates the number of standard valves. Indicates the first One gas source point, and All of these represent standard valve numbers. Indicates the gas source number. Indicates the first From the first gas source point to the... The shortest path distance between conventional valves Indicates conventional valves The efficiency of pipeline connectivity after failure.

[0014] Furthermore, the second calculation formula for obtaining the valve flow rate index is as follows:

[0015] ;

[0016] in, Indicates conventional valves Valve flow rate index Indicates conventional valves Excessive flow, This indicates the total gas volume transmitted through the gas pipeline network. This indicates the standard valve number.

[0017] Furthermore, the third calculation formula for obtaining the aforementioned user number metric is as follows:

[0018] ;

[0019] in, Indicates conventional valves Impact on user numbers metrics Indicates conventional valves The number of users experiencing insufficient gas supply after the failure. This indicates the total number of users during normal gas supply. This indicates the standard valve number.

[0020] Furthermore, the specific steps for revising the weights of the importance indicators in the three-dimensional evaluation system include:

[0021] Obtain the information content of each importance index in the three-dimensional evaluation system, and determine the benchmark index based on the three-dimensional evaluation system;

[0022] Based on the amount of information, each importance indicator is compared with the benchmark indicator to obtain a relative importance ratio;

[0023] The corrected importance index weights are obtained based on the relative importance ratio.

[0024] Furthermore, the fourth formula for calculating the amount of information is as follows:

[0025] ;

[0026] in, Indicators of importance The amount of information, and All of these represent the numbers of the importance indicators. Indicates the number of standard valves. Indicates the standard valve number. Indicates conventional valves In importance index Standardized values ​​below, Indicates conventional valves In importance index Standardized values ​​below, Indicators of importance The average value, Indicators of importance The average value.

[0027] Furthermore, the fifth calculation formula for obtaining the corrected importance index weight is as follows:

[0028] ;

[0029] ;

[0030] in, Indicators of importance The ratio of relative importance to the benchmark indicator. The amount of information contained in the benchmark indicator. Indicators of importance The revised weights.

[0031] Furthermore, the sixth calculation formula of the comprehensive evaluation model is:

[0032] ;

[0033] in, Indicates conventional valves The overall importance, , and These represent the standardized values ​​of the pipeline connectivity index, valve flow rate index, and the index affecting the number of users, respectively. , and These represent the adjusted weights of the pipeline connectivity index, valve flow rate index, and number of affected users index, respectively.

[0034] Furthermore, the specific steps for determining the severity of the leakage consequences and the timeliness of emergency response for the critical valve include:

[0035] The severity of leakage consequences is determined by obtaining the valve overflow rate of the key valve during peak winter gas consumption. The seventh formula for calculating the severity of leakage consequences is as follows:

[0036] ;

[0037] in, Indicates key valves The assessment value of the consequences of leakage, Key valves indicating peak gas consumption in winter Overflow;

[0038] Several emergency rescue duty points were identified, and these duty points were sequentially marked as follows: , This indicates the location of the first guard point. Indicates the first The location of each guard point Indicates the number of guard points;

[0039] Starting from the designated guard point and ending at the critical valve, the longest time required for manually closing the valve during peak vehicle hours is obtained. The emergency response timeliness is then calculated based on the maximum value of this longest time. The eighth formula for calculating the emergency response timeliness is as follows:

[0040] ;

[0041] in, This indicates the emergency response timeliness assessment value for the critical valve c. Indicates the guard point To the critical valve The duration of manual valve closure, Indicates the guard point To the critical valve The duration of manual valve closure, This indicates the number of the key valve.

[0042] Furthermore, the ninth calculation formula of the remote emergency shut-off valve modification priority evaluation model is:

[0043] ;

[0044] in, Indicates key valves Priority for conversion to a remote emergency shut-off valve;

[0045] The key valves are arranged in descending order of priority to obtain a valve sequence. Based on the arrangement order of the valve sequence and the modification rules, modification schemes for the key valves are determined sequentially. The valve positions corresponding to the modification schemes are obtained to obtain the modification points. The modification rules are as follows:

[0046] If there are at least two critical valves in the gas pipeline within the preset area, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve.

[0047] For gas pipelines not located within the preset area, if there are at least two critical valves on the same main pipe, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve.

[0048] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0049] This method establishes three valve importance indices by comprehensively considering the topological attributes of the gas pipeline network, the gas transmission and distribution attributes, and the impact on gas supply after failure. It also modifies the subjective weighting of these indices to ensure the rationality of the weight allocation, thereby constructing a comprehensive evaluation model to accurately identify critical valves in the operating urban gas pipeline network. Based on the severity of the consequences of critical valve leaks and the timeliness of emergency response, a priority evaluation model for remote emergency shut-off valve retrofitting is constructed. Retrofitting is evaluated sequentially based on priority ranking, fully considering the actual application scenarios of remote emergency shut-off valves, reducing retrofitting costs, improving the rationality of retrofitting site selection, and further strengthening the safe operation guarantee of the operating gas pipeline network. Attached Figure Description

[0050] The accompanying drawings, which are provided to further illustrate embodiments of the invention and constitute a part of this invention, are not intended to limit the scope of the invention.

[0051] Figure 1 This is a flowchart illustrating a method for selecting locations for the remote emergency shut-off valve modification of an in-service urban gas pipeline network according to the present invention.

[0052] Figure 2 This is a schematic diagram of the active urban gas pipeline network in the example area;

[0053] Figure 3 This is a comparison chart of the connection efficiency between the gas source and each valve point when the sample area is under normal gas supply and after valve-2 fails.

[0054] Figure 4 This is a sample diagram showing the calculation and analysis of the pipeline connectivity index in the area.

[0055] Figure 5 This is a sample diagram showing the calculation and analysis of the valve flow rate index in the area.

[0056] Figure 6 This is a chart showing the calculation and analysis of the user count metric for an example area;

[0057] Figure 7 This is a sample diagram showing the overall importance calculation and analysis of valves in a given area.

[0058] Figure 8 This is a sample area key valve distribution map;

[0059] Figure 9 This is a distribution map of the remote emergency shut-off valve modification points in the example area. Detailed Implementation

[0060] To better understand the above-mentioned objectives, features, and advantages of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. It should be noted that, where there is no conflict, the embodiments of the present invention and the features thereof can be combined with each other.

[0061] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and therefore the scope of protection of the invention is not limited to the specific embodiments disclosed below.

[0062] Example 1

[0063] refer to Figure 1 This embodiment provides a method for selecting locations for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network. The method includes:

[0064] A three-dimensional evaluation system is constructed, which includes indicators of pipeline connectivity, valve flow rate, and number of affected users. The weights of the importance indicators in the three-dimensional evaluation system are then adjusted.

[0065] The first calculation formula for obtaining the pipeline connectivity index is as follows:

[0066] Equation (1)

[0067] Equation (2)

[0068] in, Indicates conventional valves Pipeline connectivity indicators; This indicates the pipeline connectivity efficiency when the gas pipeline is supplying gas normally. Indicates the number of gas source points; Indicates the number of standard valves; Indicates the first One gas source point; and All of these represent standard valve numbers; Indicates the gas source point number; Indicates the first From the first gas source point to the... The shortest path distance between conventional valves; Indicates conventional valves The efficiency of pipeline connectivity after failure. Calculation method and The same applies when the gas source and conventional valves When there are disconnected conditions, .

[0069] The second calculation formula for obtaining the valve flow rate index is as follows:

[0070] Equation (3)

[0071] in, Indicates conventional valves Valve flow rate index; Indicates conventional valves Flow rate, m³ / min; This indicates the total gas transmission volume of the gas pipeline network, in m³ / min; This indicates the standard valve number.

[0072] The third calculation formula for obtaining the number of affected users is as follows:

[0073] Equation (4)

[0074] in, Indicates conventional valves The impact on user numbers metrics; Indicates conventional valves The number of users experiencing insufficient gas supply after the failure; This indicates the total number of users during normal gas supply. This indicates the standard valve number.

[0075] The specific steps for correcting the importance index weights of the three-dimensional evaluation system include:

[0076] Obtain the information content of each importance index in the three-dimensional evaluation system, and determine the benchmark index based on the three-dimensional evaluation system; for example, according to expert opinions, determine the index with the lowest relative importance among the pipeline connectivity index, valve flow rate index and number of affected users index as the benchmark index.

[0077] Based on the amount of information, each importance indicator is compared with the benchmark indicator to obtain a relative importance ratio;

[0078] The corrected importance index weights are obtained based on the relative importance ratio.

[0079] The fourth formula for calculating the amount of information is as follows:

[0080] Equation (5)

[0081] in, Indicators of importance The amount of information; and All of these represent the numbers of the importance indicators; Indicates the number of standard valves; Indicates the standard valve number; Indicates conventional valves In importance index Standardized values ​​below, Indicates conventional valves In importance index The standardized values ​​can be obtained using the range method; Indicators of importance The average value, Indicators of importance The average value.

[0082] The fifth calculation formula for obtaining the corrected importance index weight is as follows:

[0083] Equation (6)

[0084] Equation (7)

[0085] in, Indicators of importance The ratio of relative importance to the benchmark indicator; The amount of information representing the benchmark indicator; Indicators of importance The revised weights.

[0086] A comprehensive evaluation model is constructed based on the three-dimensional evaluation system and the modified importance index weights, and several key valves are identified based on the comprehensive evaluation model.

[0087] In this embodiment, the comprehensive evaluation model combines existing urban gas pipeline network maps, conventional valve data, or urban gas pipeline network simulation models to identify key valves.

[0088] The comprehensive evaluation model ranks each conventional valve according to its overall importance and selects a certain number of conventional valves as key valves.

[0089] The sixth calculation formula of the comprehensive evaluation model is as follows:

[0090] Equation (8)

[0091] in, Indicates conventional valves The overall importance is indicated by a higher value, meaning the valve is more important. , and These represent the standardized values ​​of the pipeline connectivity index, valve flow rate index, and number of affected users index, respectively, which can be calculated using the range method. , and These represent the adjusted weights of the pipeline connectivity index, valve flow rate index, and number of affected users index, respectively.

[0092] In this embodiment, measures for handling key valves in the urban gas pipeline network in service can also be proposed:

[0093] For critical valves in service, old valves should be upgraded to more reliable and higher-quality valve equipment, provided that it is economically feasible. For critical valve locations that require emergency shut-off functions, the conventional shut-off valves at these locations should be upgraded to remote emergency shut-off valves. For critical valve locations that are not equipped with remote emergency shut-off valves, the frequency of manual inspections should be increased to detect valve abnormalities in a timely manner.

[0094] Based on the severity of the leakage consequences and the timeliness of emergency response of the key valves, a priority evaluation model for the modification of remote emergency shut-off valves is constructed, and the modification points of remote emergency shut-off valves in the urban gas pipeline network in service are determined based on the remote emergency shut-off valve modification priority evaluation model.

[0095] The valve flow rate directly determines the potential scale and scope of valve leakage; the larger the value, the more severe the leakage consequences. Considering the worst-case scenario, the valve flow rate during peak gas consumption in winter can be used as an indicator of the severity of the leakage consequences.

[0096] The specific steps for determining the severity of the leakage consequences and the timeliness of emergency response for the key valve include:

[0097] The severity of the leakage consequences is determined by obtaining the valve overflow rate of the key valve during peak gas consumption in winter. The seventh formula for calculating the severity of the leakage consequences is as follows:

[0098] Equation (9)

[0099] in, Indicates key valves The leakage consequence assessment value, m³ / min; Key valves indicating peak gas consumption in winter The flow rate is m³ / min.

[0100] Several emergency rescue duty points were identified, and these duty points were sequentially marked as follows: , This indicates the location of the first guard point. Indicates the first The location of each guard point Indicates the number of guard points;

[0101] Considering the worst-case scenario, taking the guard point as the starting point and the key valve as the ending point, the longest time required for manually closing the valve during peak vehicle hours is obtained. Based on the maximum value of the longest time, the emergency response timeliness is obtained. The eighth calculation formula for the emergency response timeliness is:

[0102] Equation (10)

[0103] in, The value for assessing the timeliness of emergency response for the critical valve c is expressed in min. Indicates the guard point To the critical valve The duration of manual valve closure, in minutes; Indicates the guard point To the critical valve The duration of manual valve closure, in minutes; This indicates the number of the key valve.

[0104] The ninth calculation formula of the remote emergency shut-off valve modification priority evaluation model is:

[0105] Equation (11)

[0106] in, Indicates key valves The priority of converting to a remote emergency shut-off valve, in m³; the larger this value, the more severe the consequences of leakage during the time it takes for emergency personnel to reach the scene if the valve leaks.

[0107] The key valves are arranged in descending order of priority to obtain a valve sequence. Based on the arrangement order of the valve sequence and the modification rules, modification schemes for the key valves are determined sequentially. The valve positions corresponding to the modification schemes are obtained to obtain the modification points. The modification rules are as follows:

[0108] If there are at least two critical valves in the gas pipeline within the preset area, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve.

[0109] For gas pipelines not located within the preset area, if there are at least two critical valves on the same main pipe, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve.

[0110] Example 2

[0111] refer to Figure 1 This embodiment takes the existing urban gas pipeline network in a certain area as an example to illustrate the process of obtaining the location of the remote emergency shut-off valve.

[0112] Figure 2 This is a schematic diagram of the urban gas pipeline network in service in this area. A pipeline network simulation model can be established based on this model, and the importance index can be calculated based on this model.

[0113] Pipeline connectivity indicators:

[0114] In complex network theory, the importance of a component of a pipeline network can be measured by simulating its failure and assessing the resulting decrease in network connectivity efficiency. Urban gas pipeline networks are complex networks; therefore, improvements to complex network theory are used to evaluate the importance of a specific valve.

[0115] Instead of physical distance in the real world, path distance is used. A path is the route taken along the edges of a network, and its distance is measured by the number of edges traversed. The path with the fewest edges among all possible paths is called the shortest path.

[0116] The reciprocal of the shortest path distance between the gas source point and the valve point is defined as the connectivity efficiency, and the sum of the connectivity efficiencies between the gas source point and each valve point is defined as the pipeline connectivity efficiency.

[0117] The degree of decrease in pipeline connectivity efficiency after a valve fails is used as an indicator to evaluate the valve's importance. The higher the valve's importance, the greater the decrease in pipeline connectivity efficiency; conversely, the lower the valve's importance, the smaller the decrease in pipeline connectivity efficiency.

[0118] by Figure 2 Taking valve-2 as an example, this simulation demonstrates a scenario where the valve fails and cannot supply gas. The comparison results of the connectivity efficiency between the gas source and each valve point are as follows: (The original text appears to be incomplete and contains errors. A more accurate translation would require the full context.) Figure 3 As shown.

[0119] The results showed that the failure of valve-2 led to a decrease in the connection efficiency between the gas source and some valve points, which in turn led to a decrease in the pipeline connection efficiency. Specifically, the pipeline connection efficiency was obtained by summing the connection efficiency between the gas source and each valve point in the two cases according to equation (1). The failure of valve-2 caused the pipeline connection efficiency to decrease from 8.8505 when the gas supply was normal to 4.8134. According to equation (2), the pipeline connectivity index of valve-2 was calculated to be 0.4561.

[0120] An analysis of the valves in the entire example area's pipeline network was conducted, and the calculation results of the pipeline connectivity index are as follows: Figure 4 As shown.

[0121] Valve flow rate index:

[0122] Valve flow rate refers to the proportion of gas flow through a valve to the total gas flow in the pipeline network per unit time. This indicator characterizes the flow capacity of valves in the pipeline network. The higher the value, the greater the flow rate delivered by the valve, indicating the greater the importance of the valve.

[0123] Taking the example of valve-2 in the sample area, the valve flow rate is set to 40.6626 m³ / min and the total gas transmission volume of the gas pipeline network in the area is 98.1117 m³ / min. According to formula (3), the valve flow rate index of valve-2 is 0.4145.

[0124] An analysis of the valves in the entire example area's pipeline network was conducted, and the calculated valve flow rate index results are as follows: Figure 5 As shown.

[0125] Impact on user count metrics:

[0126] Valve failure will directly affect users' normal gas supply: on the one hand, downstream users directly connected to the valve will face a complete gas supply interruption; on the other hand, valve failure will also cause a drop in the overall gas supply pressure of the pipeline network, resulting in low gas supply pressure for other users who are not directly related.

[0127] Therefore, using the number of users experiencing insufficient gas supply due to valve failure as a core indicator to characterize the degree of user impact can intuitively quantify the user impact range of pipeline network failures, thereby providing a key basis for assessing the importance of the valve.

[0128] Taking valve-2 in the example area as an example, the failure of the valve is simulated, resulting in the inability to supply gas. Although there is no direct interruption of gas supply to downstream users, the valve is located in a critical position in the ring network, and the failure of the valve causes a drop in the overall gas supply pressure of the pipeline network. According to the simulation results, the number of users unable to supply gas normally reaches 3818 households. The total number of users in this area when gas supply is normal is 5887 households. According to formula (4), the number of users affected by valve-2 is calculated to be 0.6485.

[0129] An analysis of the valves in the entire example area's pipeline network was conducted, and the calculation results of the impact on the number of users are as follows: Figure 6 As shown.

[0130] Determine the weights of importance indicators:

[0131] The standard values ​​of the importance index calculation results are obtained by processing the range method, and the information content of the index is calculated according to equation (5). .

[0132] Based on expert opinions, the pipeline connectivity index was determined as the benchmark index. According to equation (6) and the information quantity calculation results, the ratio of the relative importance of each index to the benchmark index was obtained. Finally, the weights of each importance index are obtained according to equation (7), and the results are shown in Table 1.

[0133] Table 1. Weight Analysis of Importance Indicators

[0134]

[0135] Calculate the overall importance:

[0136] Based on equation (8), the overall importance of each valve in the example area was analyzed and calculated. The detailed results are shown in Table 2. Figure 7 From the 33 valves, 11 key valves were identified. The distribution of key valves in an example area is shown below. Figure 8 As shown.

[0137] Corresponding measures were proposed for the key valves in this area:

[0138] For critical valves in service, old valves should be upgraded to more reliable and higher-quality valve equipment, provided that it is economically feasible. For critical valve locations that require emergency shut-off functions, the conventional shut-off valves at these locations should be upgraded to remote emergency shut-off valves. For critical valve locations that are not equipped with remote emergency shut-off valves, the frequency of manual inspections should be increased to detect valve abnormalities in a timely manner.

[0139] Table 2. Calculation Results of Overall Importance of Valves in Example Areas

[0140]

[0141] The specific steps for obtaining the location of the remote emergency shut-off valve modification include:

[0142] Analyze the severity of consequences of leakage from critical valves:

[0143] The valve overflow rate at the peak gas consumption time in winter is selected as the assessment value for leakage consequences, and its value is calculated according to formula (9). The results of the severity analysis of leakage consequences of key valves in this example area are shown in Table 3.

[0144] Analysis of the timeliness of emergency response for critical valves:

[0145] This example area has two emergency duty points. Taking the emergency duty points at different locations as the starting point and the key valve as the ending point, the longest time required to manually close the valve during peak hours is predicted and calculated using navigation software according to equation (10). The results of the emergency response timeliness analysis of the key valve in this example area are shown in Table 3.

[0146] Analysis of the priority of key valve modification:

[0147] Prioritize the conversion of key valves in the example area into remote emergency shut-off valves according to formula (11). The analysis and calculations were performed, and the detailed results are shown in Table 3.

[0148] Table 3. Priority Analysis of Key Valve Upgrades in Example Areas

[0149]

[0150] Identify locations for retrofitting remote emergency shut-off valves in existing urban gas pipeline networks:

[0151] Based on relevant standards and on-site statistics of valve spacing data from multiple gas companies, the results are shown in Table 4. It can be seen that the standard valve spacing is mainly 1-2 km. To standardize the deployment of remote emergency shut-off valves and maximize their effectiveness, the final valve spacing was determined to be 2 km.

[0152] Table 4. Statistics on valve spacing data of gas companies

[0153]

[0154] Calculate the values ​​of each key valve Value, by The critical valves were evaluated one by one in descending order of their values ​​to determine if they were suitable for conversion into remote emergency shut-off valves. The analysis process is shown in Table 5. The final example area's remote emergency shut-off valve conversion points are as follows: Figure 9 As shown.

[0155] Table 5. Evaluation and Analysis of Key Valve Modification in Example Areas

[0156]

[0157] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention.

[0158] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A method for selecting a site for retrofitting a remote emergency shut-off valve for an in-service urban gas pipeline network, characterized in that, The method includes: A three-dimensional evaluation system is constructed, which includes indicators of pipeline connectivity, valve flow rate, and number of affected users. The weights of the importance indicators in the three-dimensional evaluation system are then adjusted. A comprehensive evaluation model is constructed based on the three-dimensional evaluation system and the corrected importance index weights. Several key valves are then identified based on the comprehensive evaluation model. Based on the severity of the leakage consequences and the timeliness of emergency response of the key valves, a priority evaluation model for the modification of remote emergency shut-off valves is constructed, and the modification points of remote emergency shut-off valves in the urban gas pipeline network in service are determined based on the priority evaluation model for the modification of remote emergency shut-off valves. The specific steps for revising the importance index weights of the three-dimensional evaluation system include: Obtain the information content of each importance index in the three-dimensional evaluation system, and determine the benchmark index based on the three-dimensional evaluation system; Based on the amount of information, each importance indicator is compared with the benchmark indicator to obtain a relative importance ratio; The corrected importance index weights are obtained based on the relative importance ratio; The first calculation formula for obtaining the pipeline connectivity index is: ； ； in, Indicates conventional valves Pipeline connectivity indicators This indicates the pipeline connectivity efficiency when the gas pipeline network is supplying gas normally. Indicates the number of gas source points. Indicates the number of standard valves. Indicates the first One gas source point, and All of these represent standard valve numbers. Indicates the gas source number. Indicates the first From the first gas source point to the... The shortest path distance between conventional valves Indicates conventional valves The efficiency of pipeline connectivity after failure; The fourth formula for calculating the amount of information is: ； in, Indicators of importance The amount of information, and All of these represent the numbers of the importance indicators. Indicates the number of standard valves. Indicates the standard valve number. Indicates conventional valves In importance index Standardized values ​​below, Indicates conventional valves In importance index Standardized values ​​below, Indicators of importance The average value, Indicators of importance The average value; The fifth calculation formula for obtaining the corrected importance index weights is: ； ； in, Indicators of importance The ratio of relative importance to the benchmark indicator. The amount of information contained in the benchmark indicator. Indicators of importance The revised weights.

2. The method for selecting sites for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network according to claim 1, characterized in that, The second formula for obtaining the valve flow rate index is: ； in, Indicates conventional valves Valve flow rate index Indicates conventional valves Excessive flow, This indicates the total gas volume transmitted through the gas pipeline network. This indicates the standard valve number.

3. The method for selecting sites for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network according to claim 1, characterized in that, The third calculation formula for obtaining the aforementioned metric of the number of affected users is: ； in, Indicates conventional valves Impact on user numbers metrics Indicates conventional valves The number of users experiencing insufficient gas supply after the failure. This indicates the total number of users during normal gas supply. This indicates the standard valve number.

4. The method for selecting sites for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network according to claim 1, characterized in that, The sixth calculation formula of the comprehensive evaluation model is: ； in, Indicates conventional valves The overall importance, , and These represent the standardized values ​​of the pipeline connectivity index, valve flow rate index, and the index affecting the number of users, respectively. , and These represent the adjusted weights of the pipeline connectivity index, valve flow rate index, and number of affected users index, respectively.

5. The method for selecting sites for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network according to claim 1, characterized in that, The specific steps for determining the severity of the leakage consequences and the timeliness of emergency response for the critical valve include: The severity of the leakage consequences is determined by obtaining the valve overflow rate of the key valve during peak gas consumption in winter. The seventh formula for calculating the severity of the leakage consequences is as follows: ； in, Indicates key valves The assessment value of the consequences of leakage, Key valves indicating peak gas consumption in winter Overflow; Several emergency rescue duty points were identified, and these duty points were sequentially marked as follows: , This indicates the location of the first guard point. Indicates the first The location of each guard point Indicates the number of guard points; Starting from the designated guard point and ending at the critical valve, the longest time required for manually closing the valve during peak vehicle hours is obtained. The emergency response timeliness is then calculated based on the maximum value of this longest time. The eighth formula for calculating the emergency response timeliness is as follows: ； in, This indicates the emergency response timeliness assessment value for the critical valve c. Indicates the guard point To the critical valve The duration of manual valve closure, Indicates the guard point To the critical valve The duration of manual valve closure, This indicates the number of the key valve.

6. The method for selecting sites for the retrofitting of remote emergency shut-off valves in an in-service urban gas pipeline network according to claim 5, characterized in that, The ninth calculation formula of the remote emergency shut-off valve modification priority evaluation model is: ； in, Indicates key valves Priority should be given to converting it into a remote emergency shut-off valve; The key valves are arranged in descending order of priority to obtain a valve sequence. Based on the arrangement order of the valve sequence and the modification rules, modification schemes for the key valves are determined sequentially. The valve positions corresponding to the modification schemes are obtained to obtain the modification points. The modification rules are as follows: If there are at least two critical valves in the gas pipeline within the preset area, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve. For gas pipelines not located within the preset area, if there are at least two critical valves on the same main pipe, the critical valve located at the upstream position will be converted into a remote emergency shut-off valve.

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