Pipeline replacement planning system and pipeline replacement planning method

Abstract

[Problem] To provide a pipeline replacement planning system capable of planning a replacement plan with high economic efficiency for a pipeline having a high water leakage probability. [Solution] The pipeline replacement planning system comprises: a pipeline data acquisition unit that acquires pipeline data of each pipeline required for hydraulic analysis; a water leakage accident rate calculation unit that calculates, for each pipeline, a predicted value of a water leakage accident rate at a predetermined period; a hydraulic analysis unit that executes hydraulic analysis of the pipeline network on the basis of the pipeline data; a water failure occurrence pipeline estimation unit that activates the hydraulic analysis unit on the assumption that a water leakage accident has occurred in a specific pipeline on the basis of the predicted value, and repeats processing of estimating a water failure occurrence pipeline for different specific pipelines on the basis of a result of the hydraulic analysis; a water failure influence degree calculation unit that calculates a water failure influence degree by each water failure occurrence pipeline estimated by the water failure occurrence pipeline estimation unit; and a replacement priority setting unit that sets replacement priority for the specific pipeline on the basis of the water failure influence degree calculated by the water failure influence degree calculation unit.

Description

Pipeline replacement planning system and pipeline replacement planning method

[0001] The present invention relates to a pipeline renewal plan formulation system and a pipeline renewal plan formulation method.

[0002] To address the aging of existing pipelines and mitigate earthquake damage, there is a need for efficient renewal plans for each pipeline that makes up the pipeline network.

[0003] Patent Document 1 proposes a buried pipe replacement timing prediction device that includes a buried pipe attribute data acquisition unit for acquiring attribute data of buried pipes, the attribute data including a first environmental factor including the soil type and soil resistance of the buried pipe, a first burial period and an allowable corrosion depth, and a pipe replacement timing prediction unit that further calculates the time at which the corrosion depth of the buried pipe reaches the allowable corrosion depth from the first environmental factor, the first burial period and the allowable corrosion depth and outputs the time at which the corrosion depth reaches the allowable corrosion depth.

[0004] Japanese Patent Publication No. 2021-56224

[0005] Patent Document 1 describes a method for determining pipelines that are nearing the time when they will reach their allowable corrosion depth as pipelines with a high probability of leakage, and then formulating a pipeline renewal plan with the aim of preventing leakage accidents.

[0006] However, because the impact on consumers from individual water leak incidents is unknown, simply prioritizing pipelines with a high probability of leaks when formulating pipeline replacement plans is not necessarily an efficient approach.

[0007] The objective of the present invention is to provide a pipeline renewal planning system and a pipeline renewal planning method that enable the formulation of renewal plans with high economic efficiency for pipelines with a high probability of leakage.

[0008] To achieve the above objectives, the first characteristic configuration of the pipeline renewal plan formulation system according to the present invention is a pipeline renewal plan formulation system that formulates renewal plans for each pipeline constituting a pipeline network according to calculation processing by a processor, comprising: a pipeline data acquisition unit that acquires pipeline data constituting the pipeline network necessary for formulating a pipeline renewal plan; a leakage accident rate calculation unit that calculates a predicted value of the leakage accident rate [incidents / year / km] at a predetermined time for each pipeline; a hydraulic analysis unit that performs hydraulic analysis of the pipeline network based on the pipeline data; a pipeline outage estimation unit that starts the hydraulic analysis unit under the assumption that a leakage accident has occurred in a specific pipeline based on predetermined conditions and repeats the process of estimating the pipeline that will experience a water outage based on the results of the hydraulic analysis for different specific pipelines; a water outage impact calculation unit that calculates the degree of water outage impact by each pipeline that will experience a water outage estimated by the water outage estimation unit; and a renewal priority setting unit that sets the renewal priority for the specific pipelines based on the degree of water outage impact calculated by the water outage impact calculation unit.

[0009] As a predetermined condition, for example, it can be assumed that water leakage accidents occur in pipelines where the predicted water leakage accident rate [accidents / year / km] calculated by the water leakage accident rate calculation unit is relatively high. The water outage pipeline estimation unit starts the hydraulic analysis unit by treating pipelines with high water leakage accident rates as hypothetical water leakage accident pipelines where water leakage accidents have occurred, and estimates pipelines that are likely to experience water outages as water outage pipelines based on the analysis results. The water outage impact calculation unit calculates the water outage impact for the water outage pipelines estimated by the water outage pipeline estimation unit. The renewal priority setting unit sets hypothetical water leakage accident pipelines that show a relatively high water outage impact as high-priority renewal pipelines, thereby enabling the formulation of a renewal plan with high economic efficiency. The predetermined conditions are not limited to those described above; for example, all pipelines may be designated as specific pipelines in the order of their assigned pipeline numbers.

[0010] The second characteristic configuration is that, in addition to the first characteristic configuration described above, the water outage occurrence pipeline estimation unit estimates that pipelines where the water pressure falls below a standard value are water outage occurrence pipelines based on the results of the hydraulic analysis.

[0011] In a hypothetical leak, it can be estimated that a water outage will occur in a pipeline where the water pressure falls below a standard value due to the influence of the leak. The specific value of the standard is not limited and can be set as appropriate.

[0012] The third characteristic configuration is that, in addition to the second characteristic configuration described above, the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the population affected by the water outage [people / incident], which is calculated by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per person.

[0013] By calculating the impact of a water outage as the product of the estimated leakage accident rate [incidents / year / km], the pipeline length of the affected pipeline [km], and the population affected by the water outage [people / incident] (calculated by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per person), it becomes possible to objectively evaluate the degree of impact of a water outage occurring in a hypothetical pipeline with a leakage accident in terms of population.

[0014] The fourth characteristic configuration is that, in addition to the second characteristic configuration described above, the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is calculated by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per household.

[0015] By calculating the impact of a water outage as the product of the estimated leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of affected households [households / incident] obtained by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per household, it becomes possible to objectively evaluate the degree of impact of a water outage occurring in a hypothetical pipeline with a leakage accident in terms of the number of households affected.

[0016] The fifth characteristic feature is that, in addition to the second characteristic feature described above, the degree of impact of the water outage is expressed as the product of the estimated leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is the total number of water supply pipes connected to the pipeline where the water outage occurred.

[0017] By calculating the impact of a water outage as the product of the estimated leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of households affected by the outage [households / incident] (the total number of water supply pipes connected to the pipeline where the outage occurred), it becomes possible to objectively evaluate the degree of impact of a water outage occurring in a hypothetical pipeline with a leakage accident, expressed in terms of the number of households affected. This can be easily calculated under the assumption that one water supply pipe is laid from the pipeline functioning as a water distribution pipe to each household.

[0018] The sixth characteristic configuration is that, in addition to any of the third to fifth characteristic configurations described above, the water outage impact is calculated by adding the probability of water outages occurring in each pipeline due to water leakage accidents, which is obtained from cumulative data of past water leakage accidents.

[0019] If we have cumulative data from past water leakage incidents, we can determine the probability of a water outage occurring in a hypothetical pipeline where a leak occurred. By adding the probability of a water outage to the impact of the water outage, we can obtain a more accurate probability of a water outage occurring.

[0020] The seventh characteristic configuration is that, in addition to any of the third to fifth characteristic configurations described above, the impact of the water outage is also taken into account the number of days required to restore each pipeline in response to a water leak.

[0021] Knowing the estimated number of days required to repair a leak in a hypothetical pipeline allows for a more accurate assessment of the impact of the repair process.

[0022] The first characteristic configuration of the pipeline renewal plan formulation method according to the present invention is a pipeline renewal plan formulation method that formulates a renewal plan for each pipeline constituting a pipeline network according to calculation processing by a processor, comprising: a pipeline data acquisition step of acquiring pipeline data constituting the pipeline network necessary for formulating the pipeline renewal plan; a leakage accident rate calculation step of calculating a predicted value of the leakage accident rate [incidents / year / km] at a predetermined time for each pipeline; a hydraulic analysis step of performing a hydraulic analysis of the pipeline network based on the pipeline data; a water outage occurrence pipeline estimation step of performing the hydraulic analysis step under the assumption that a leakage accident has occurred in a specific pipeline based on predetermined conditions, and repeating the process of estimating the pipeline where the water outage occurred based on the results of the hydraulic analysis for different specific pipelines; a water outage impact calculation step of calculating the degree of water outage impact by each water outage occurrence pipeline estimated in the water outage occurrence pipeline estimation step; and a renewal priority setting step of setting the renewal priority for the specific pipelines based on the water outage impact calculated in the water outage impact calculation step.

[0023] The second characteristic configuration is that, in addition to the first characteristic configuration described above, the water outage occurrence pipeline estimation step estimates the pipeline where the water pressure falls below a standard value based on the results of the hydraulic analysis as the water outage occurrence pipeline.

[0024] The third characteristic configuration is that, in addition to the second characteristic configuration described above, the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the population affected by the water outage [people / incident], which is calculated by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per person.

[0025] The fourth characteristic configuration is that, in addition to the second characteristic configuration described above, the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is calculated by dividing the amount of water lost in the pipeline where the water outage occurred by the amount of water used per household.

[0026] The fifth characteristic feature is that, in addition to the second characteristic feature described above, the degree of impact of the water outage is expressed as the product of the estimated leakage accident rate [incidents / year / km], the length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is the total number of water supply pipes connected to the pipeline where the water outage occurred.

[0027] The sixth characteristic configuration is that, in addition to any of the third to fifth characteristic configurations described above, the water outage impact is calculated by adding the probability of water outages occurring in each pipeline due to water leakage accidents, which is obtained from cumulative data of past water leakage accidents.

[0028] The seventh characteristic configuration is that, in addition to any of the third to fifth characteristic configurations described above, the impact of the water outage is also taken into account the number of days required to restore each pipeline in response to a water leak.

[0029] As described above, the present invention provides a pipeline renewal planning system and a pipeline renewal planning method that enable the formulation of renewal plans with high economic efficiency for pipelines with a high probability of water leakage.

[0030] Figure 1 is an explanatory diagram of the pipeline replacement plan formulation system according to the present invention. Figure 2A is an explanatory diagram of the hydraulic analysis method. Figure 2B is an explanatory diagram of the hydraulic analysis method. Figure 3 is a flowchart of the pipeline replacement plan formulation procedure. Figure 4A is an explanatory diagram of the mapping process for identifying water supply pipes connected to each pipeline (distribution pipe) from the pipeline diagram. Figure 4B is an explanatory diagram of the mapping process for identifying water supply pipes connected to each pipeline (distribution pipe) from the pipeline diagram. 5A is an explanatory diagram of the impact of water outages caused by pipelines experiencing water outages in a hypothetical pipeline with a water leak. Figure 5B is an explanatory diagram of the impact of water outages caused by pipelines experiencing water outages in a hypothetical pipeline with a water leak. Figure 6 is an explanatory diagram of the table data used to calculate the impact of water outages.

[0031] The pipeline renewal plan formulation system and pipeline renewal plan formulation method according to the present invention will be described below with reference to the drawings.

[0032] [Configuration of the Pipeline Replacement Planning System] The pipeline replacement planning system can be configured using a general-purpose personal computer, for example, one that incorporates a motherboard with a CPU and a memory board with semiconductor memory. This personal computer is connected to storage devices such as hard disks and SSDs, a touch-panel LCD display as a display unit, and input / output devices such as a keyboard and mouse as input units via input / output interface circuits, and is also configured to connect to a cloud server that functions as an external database via a communication interface circuit.

[0033] The storage device has an OS program installed to manage the system, and application programs such as a pipeline renewal planning program, a hydraulic analysis program, and a leakage accident rate analysis program are installed as application programs executed by the CPU under the management of the OS program. These application programs may be pre-written to optical discs such as CD-ROMs or DVD-ROMs, or to non-volatile semiconductor memory such as USB memory, and configured to be read to the storage device via a personal computer, or they may be downloaded to the storage device from a cloud server via a communication interface circuit.

[0034] As shown in Figure 1, the pipeline renewal planning system 1 comprises a calculation processing unit 2, a storage unit 3, a display unit 4, an input unit 5, etc., and is connected to a cloud server that functions as a database server. The calculation processing unit 2 includes functional blocks such as a job management unit 20, a pipeline data acquisition unit 21, a leakage accident rate calculation unit 22, a hydraulic analysis unit 23, a pipeline outage estimation unit 24, a water outage impact calculation unit 25, a renewal priority setting unit 26, and a mapping processing unit 27. These functional blocks are realized by application programs such as a pipeline renewal planning program, a hydraulic analysis program, and a deterioration analysis program, and integrated circuits including a CPU that executes these application programs.

[0035] The storage unit 3 is configured by a storage device, and is divided into a plurality of data storage areas including a pipeline diagram storage unit 30, a pipeline attribute data storage unit 31, a pipeline laying environment data storage unit 32, a water leakage accident rate data storage unit 33, a water outage impact degree calculation data storage unit 34, and an update plan data storage unit 35.

[0036] The job management unit 20 is a block that manages the basic operations of the pipeline renewal planning system 1. When the power is turned on and the pipeline renewal planning system 1 is started up, it manages the formulation work of the pipeline renewal plan by activating the pipeline data acquisition unit 21, the water leakage accident rate calculation unit 22, the hydraulic analysis unit 23, the water outage occurrence pipeline estimation unit 24, the water outage impact degree calculation unit 25, and the update priority setting unit 26 as necessary.

[0037] The pipeline data acquisition unit 21 is a functional block that acquires pipeline data required for formulating a pipeline renewal plan and accumulated data of past water leakage accidents from, for example, a pipeline network database provided in a geographic information system (GIS) managed by a pipeline network administrator, and stores the acquired data in the pipeline diagram storage unit 30, the pipeline attribute data storage unit 31, the pipeline laying environment data storage unit 32, and the water leakage accident rate data storage unit 32 respectively.

[0038] The pipeline diagram storage unit 30 stores map information and pipeline diagrams that constitute the existing pipeline network associated with the map information. The pipeline attribute data storage unit 31 stores attribute data including connection information such as the pipe type, nominal diameter, pipeline length, position of connection points (intersection points), burial year (which allows grasping the number of years elapsed since burial), and the number of water supply pipes connected to each pipe constituting the pipeline diagram. The pipeline laying environment data storage unit 32 stores division data indicating the burial environment characterized by the geology and / or ground of the area where the pipeline is buried (for example, polygon data managed by a geographic information system (GIS)).

[0039] The water leakage accident rate calculation unit 22 is a functional block that calculates the predicted value of the water leakage accident rate Wr [cases / year / km] for each pipe line at a predetermined time period, and stores the calculated predicted value in the water leakage accident rate data storage unit 33. The water leakage accident rate calculation unit 22 calculates the water leakage accident rate Wr [cases / year / km] under normal conditions excluding disasters such as earthquakes based on, for example, the following estimation formula, thereby estimating pipe lines with high aging degree and high possibility of water leakage accidents. Water leakage accident rate Wr [cases / year / km] = R1・R2・R3・F(T) Here, F(T) is a standard accident rate curve for each pipe type F(T) = a・T ｂ , T is the number of elapsed years, R1 is a correction coefficient related to pipe specifications, R2 is a correction coefficient based on pipe diameter, R3 is a buried ground correction coefficient, and a and b are coefficients for each pipe type representing the degree of increase in the water leakage accident rate Wr over time.

[0040] The above estimation formula is an estimation formula for the water leakage accident rate Wr of buried pipes provided by the Japan Water Research Center. Note that the estimation formula for the water leakage accident rate Wr is not limited to the above formula, and other estimation formulas can also be used. It is also possible to adopt an AI analysis method using a decision tree algorithm that estimates the water leakage accident rate Wr [cases / year / km] based on the aforementioned attribute data and section data indicating the buried environment.

[0041] The hydraulic analysis unit 23 is a functional block that calculates the flow direction and flow velocity of water flowing through each pipe line constituting the pipe network, the water pressure at each intersection, and the like by a predetermined hydraulic analysis algorithm. For example, when calculating the hydraulic head at each node by hydraulic analysis using the node head method, the Hazen-Williams formula is H = 10.666 × (L × Q １．８５ ) / (C １．８５ × d ４．８７ ) and the flow equation, which is the continuity condition equation for flow at nodes illustrated in FIG. 2A, Σ(±Q ｉｊ ) = P ｉ and the closed pipe equation shown in FIG. 2B, Σ(±H ｉ ) - δE ｋ = 0 can be obtained as a simultaneous solution.

[0042] Here, a node refers to an intersection of pipe lines, H is the friction loss head of the pipe (m), L is the pipe length (m), Q is the flow rate (m ３Q is the flow velocity coefficient, where d is the actual inner diameter of the pipe (m) and C is the flow velocity coefficient. ｉ P is the flow rate in each pipe connected to the node of interest. ｉ is the water supply from the node. Furthermore, the closed pipe equation states that the water within the pipeline network is distributed such that the total energy loss is minimized; that is, in a pipeline network with J pipelines, ΣQ ｊ H ｊ The flow is minimized from j=1 to J. The flow equation is used as a constraint condition for ΣQ. ｊ H ｊ →By solving for min, the closed-pipe equation can be obtained.

[0043] The value of the flow velocity coefficient C remains constant regardless of the time of day or the amount of water, and varies depending on the roughness of the inner wall of the pipe. For example, in the case of cast iron pipes, it is 130-140 for newer pipes, and decreases to 60-70 for older pipes with rust deposits on the inner wall.

[0044] The hydraulic analysis unit 23 reads necessary information such as pipe length, pipe diameter, and height of each node including the reservoir from the pipeline diagram storage unit 30 and the pipeline attribute data storage unit 31. After setting the amount of water flowing into the inflow intersection and the amount of water taken out from the water demand point (takeout intersection), it substitutes these values ​​into the above-mentioned formula to obtain a simultaneous solution, thereby determining the flow direction through each pipeline and identifying the pipelines necessary for distributing water from the reservoir to the nodes (water demand points).

[0045] The water outage pipeline estimation unit 24 is a functional block that, based on predetermined conditions, for example, the predicted value of the water leakage accident rate Wr [incidents / year / km] calculated by the water leakage accident rate calculation unit 22, assumes that a water leakage accident has occurred in one specific pipeline with a relatively high predicted value, activates the hydraulic analysis unit 23, and repeats the process of estimating the water outage pipeline based on the results of the hydraulic analysis for multiple specific pipelines where water leakage is predicted. Predetermined conditions may include, as appropriate, the order of pipeline numbers or the order of years of burial.

[0046] Specifically, the water outage pipeline estimation unit 24 selects several specific pipelines that show relatively high predicted values ​​based on the predicted values ​​of the water leakage accident rate Wr [incidents / year / km] for each pipeline at a predetermined time, specifically at the time when the pipeline renewal plan is formulated, calculated by the water leakage accident rate calculation unit 22. Assuming that a water leakage accident has occurred in one of the specific pipelines, the hydraulic analysis unit 23 is activated under the condition that the entire volume of water flowing through the specific pipeline has leaked, and the above simultaneous solution is obtained. The pipelines in which the water pressure at the nodes is below the standard value are estimated to be water outage pipelines. For example, in the flow rate Q of the formula shown in Figure 2A, the flow rate related to the specific pipeline will be set to 0.

[0047] The water outage pipeline estimation unit 24 estimates the pipelines that will experience water outages due to each water leakage incident by repeating the above process for each of the multiple specified pipelines. The number of specified pipelines is not particularly limited; pipelines whose predicted water leakage incident rate Wr [incidents / year / km] exceeds a predetermined standard value should be selected as specified pipelines. The standard value should also be set as appropriate. Furthermore, the standard value for the water pressure at the node used to determine whether or not a pipeline will experience a water outage is not particularly limited and should also be set as appropriate.

[0048] The water outage impact calculation unit 25 is a functional block that calculates the degree of water outage impact caused by the water outage-causing pipeline estimated by the water outage-causing pipeline estimation unit 24. The amount of water outage in the water outage-causing pipeline can be determined by the difference between the hydraulic analysis results when no leakage accident occurs and the hydraulic analysis results when a leakage accident occurs.

[0049] In the first embodiment, the impact of a water outage can be expressed as the product of the estimated leakage accident rate Wr [incidents / year / km], the pipeline length [km] of the pipeline in question, and the population affected by the water outage [people / incident], which is the amount of water lost in the pipeline where the water outage occurred divided by the amount of water used per person. This allows for an objective evaluation of the degree of impact of a water outage caused by a leak in a pipeline where a leak accident is assumed to have occurred (hereinafter referred to as the assumed leakage accident pipeline) as the population affected by the water outage. For example, the amount of water used per person can be the planned amount of water set during the equipment planning stage, or the amount of water supplied under normal conditions from the pipeline where the water outage is estimated to have occurred divided by the population of the water supply area.

[0050] As a second aspect, the impact of a water outage can also be expressed as the product of the estimated leakage accident rate Wr [incidents / year / km], the pipeline length of the target pipeline [km], and the number of affected households [households / incident], which is the amount of water lost in the pipeline where the water outage occurred divided by the amount of water used per household. This allows for an objective evaluation of the degree of impact of a water outage caused by a leak in a hypothetical pipeline where a leak occurred, as the number of households affected. For example, the amount of water used per household can be a predetermined planned water volume per household, the amount of water supplied under normal conditions from the pipeline where the water outage is estimated to have occurred divided by the number of households in the water supply area, or the average of the normal metered water volume for each household supplied from the pipeline where the water outage is estimated to have occurred.

[0051] As a third aspect, the impact of a water outage can also be expressed as the product of the estimated leakage accident rate Wr [incidents / year / km], the pipeline length of the target pipeline [km], and the number of households affected by the water outage [households / incident], which represents the total number of water supply pipes connected to the pipeline where the water outage occurred. As described above, this allows for an objective evaluation of the degree of impact of a water outage caused by a leak in a hypothetical pipeline in terms of the number of households affected by the water outage.

[0052] The number of water supply pipes connected to the pipelines that make up the pipeline network is basically one per household, and one water tap is provided for each water supply pipe. Therefore, the number of water supply pipes connected to each pipeline (distribution pipe) or the number of water taps attached to the water supply pipes can be considered equivalent to the number of households without water. In the case of apartment buildings supplied by a single water supply pipe, each household has a water tap, so the total number of taps can be used as a substitute.

[0053] The number of water supply pipes and taps can be determined from the water supply pipe connection information included in the attribute data of each pipeline, which is obtained from the pipeline network database by the pipeline data acquisition unit 21. Once a pipeline diagram showing pipelines (distribution pipes) and water supply pipes is obtained, and water supply pipe connection information is not present in the attribute data of each pipeline, the job management unit 20 activates the mapping processing unit 27, and the number of water supply pipes is calculated through the mapping process.

[0054] For example, Figure 4A shows a pipeline diagram of a portion of the pipeline network M obtained from the pipeline network database. Multiple water supply pipes S1 and S2 are drawn near pipeline Pn, but it is not possible to identify the pipeline to which water supply pipes S1 and S2 are actually connected. In such a case, as shown in Figure 4B, the mapping processing unit 27 expands the pipeline (distribution pipe) Pn near where water supply pipes S1 and S2 are located, determines whether the ends of water supply pipes S1 and S2 intersect with the expanded pipeline (distribution pipe) Pn, and determines that water supply pipes S1 and S2 are connected to pipeline (distribution pipe) Pn if they intersect.

[0055] Although the impact of water outages in three different ways has been described above, it is preferable to calculate the final impact of water outages by multiplying each impact level by the probability of water outages occurring and / or the number of days required for water restoration.

[0056] The probability of a water outage occurring refers to the probability that a water outage will occur due to a leak from a specific pipeline selected as a leak-causing pipeline based on the leak accident rate Wr [cases / year / km] calculated by the leak accident rate calculation unit 22. The reliability of the results can be increased by multiplying the leak accident rate Wr [cases / year / km] by the probability of a water outage occurring. The probability of a water outage occurring can be calculated by statistical processing based on past leak accident history (cumulative leak accident data) obtained from the pipeline network database. For example, the probability of a water outage occurring for past leak-causing pipelines with similar attributes to the specific pipeline can be used as the probability of a water outage occurring for the specific pipeline.

[0057] The number of days required to restore water supply is the number of days it takes to restore water supply in the event of a leak in each pipeline. This data is prepared in advance as table data based on the type of pipeline, nominal diameter, pipeline length, connection point location, and underground environment. The value takes into account that construction cannot be easily carried out during the day in areas with heavy traffic or near critical infrastructure, and that restoration work cannot be completed in a short period of time for pipelines with large nominal diameters and long pipeline lengths.

[0058] Figure 6 shows an example of a portion of an evaluation table that uses the number of households affected by water outages as the impact of water outages during normal times, and also takes into account the number of days required for water restoration and the probability of water outages occurring. For each pipeline No. that makes up the pipeline network, the pipeline length [km], the leakage accident rate Wr [accidents / year / km] during normal times excluding disasters, the predicted number of leakage accidents [accidents / year] which is the product of the pipeline length and the leakage accident rate Wr [accidents / year / km], the number of households affected by water outages when a leakage accident occurs [households / accident], the number of days required for water restoration [days], the probability of water outages occurring [%], and the impact of water outages [households / days / year] are shown. The impact of water outages [households / days / year] is calculated as the product of the pipeline length [km], the leakage accident rate Wr [accidents / year / km], the number of households affected by water outages [households / accident], the number of days required for water restoration [days], and the probability of water outages occurring [%].

[0059] The renewal priority setting unit 26 sets the renewal priority for specific pipelines based on the water outage impact calculation unit 25 and stores the data in the renewal plan data storage unit 35. By setting pipelines with a high water outage impact among the specific pipelines as pipelines with a high renewal priority, it is possible to prevent major water outages caused by leak accidents. Note that pipeline renewal work is carried out as a group, including the specific pipeline and several nearby existing pipelines.

[0060] [Explanation of Pipeline Replacement Plan Formulation Method] The pipeline replacement plan formulation method performed by the pipeline replacement plan formulation system 1 described above will be explained based on the flowchart shown in Figure 3. When the pipeline replacement plan formulation system 1 is started up, the job management unit 20 starts each functional block in a predetermined order. First, the pipeline data acquisition step (SA1) is performed by the pipeline data acquisition unit 21 to acquire pipeline data that constitutes the pipeline network necessary for formulating the pipeline replacement plan.

[0061] Next, the water leakage accident rate calculation unit 22 is activated, and a water leakage accident rate calculation step is performed to calculate a predicted value of the water leakage accident rate Wr [incidents / year / km] for each pipeline at the scheduled time of pipeline replacement work or at a predetermined time after a predetermined period thereafter (SA2). The water outage pipeline estimation unit 24 performs a water leakage pipeline identification step (SA3) to identify multiple pipelines that show relatively high predicted values ​​as specific pipelines where water leakage accidents will occur, based on the predicted values ​​of the water leakage accident rate Wr [incidents / year / km] for each pipeline calculated in the water leakage accident rate calculation step.

[0062] The water outage pipeline estimation unit 24 activates the hydraulic analysis unit 23 and executes a hydraulic analysis step (SA4) when a water leak occurs in one of the specified pipelines, and estimates the pipeline where the water outage occurred based on the results of the hydraulic analysis (SA5). Figures 5A and 5B show an example in which, among the multiple pipelines constituting the pipeline network M, pipeline Pm is selected as the specified pipeline, and the hydraulic analysis results indicate that a water outage occurred in pipelines Pn and Pn+1, which are shown by thick lines. Figure 5B also shows water supply pipes S1 and S2 connected to the water outage pipeline Pn, and water supply pipes S3 and S4 connected to the water outage pipeline Pn+1.

[0063] When the water outage pipeline estimation unit 24 executes steps SA4 and SA5 for all specific pipelines identified in the leak pipeline identification step (SA6, Y), the water outage impact calculation unit 25 is activated, the water outage impact calculation step is executed (SA7), and the renewal priority setting unit 26 sets renewal priorities in order of the specific pipelines with the highest water outage impact (SA8), which are then stored in the renewal plan data storage unit 35 (SA9). In the case of Figure 5B, since the number of water supply pipes is known, the number of households affected by the water outage can be used as the normal water outage impact. When the renewal priority setting unit 26 sets renewal priorities for multiple specific pipelines, it is preferable to set renewal priorities for multiple pipelines buried near at least one of the target specific pipelines as a group.

[0064] The pipeline renewal plan formulation program installed on the storage device described above is an application program that causes a processor to execute each step of the pipeline renewal plan formulation method described above, and comprises: a pipeline data acquisition step that acquires pipeline data constituting the pipeline network necessary for formulating a pipeline renewal plan; a leakage accident rate calculation step that calculates a predicted value of the leakage accident rate Wr [accidents / year / km] for each pipeline at a predetermined time; a hydraulic analysis step that performs a hydraulic analysis of the pipeline network based on the pipeline data; a water outage occurrence pipeline estimation step that executes the hydraulic analysis step under the assumption that a leakage accident has occurred in a specific pipeline based on the predicted value of the leakage accident rate Wr [accidents / year / km], and repeats the process of estimating the pipeline where the water outage occurred based on the results of the hydraulic analysis for different specific pipelines; a water outage impact calculation step that calculates the degree of water outage impact by each water outage occurrence pipeline estimated in the water outage occurrence pipeline estimation step; and a renewal priority setting step that sets the renewal priority for the specific pipelines based on the water outage impact calculated in the water outage impact calculation step.

[0065] The embodiments described above represent one aspect of the present invention, and the technical scope of the present invention is not limited based on this description. Furthermore, it goes without saying that the specific configuration of each part can be appropriately modified and designed within the scope that the effects of the present invention are achieved.

[0066] 1: Pipeline renewal planning system 2: Calculation processing unit 3: Memory unit 20: Job management unit 21: Data acquisition unit 22: Leakage accident rate calculation unit 23: Hydraulic analysis unit 24: Pipeline outage estimation unit 25: Water outage impact calculation unit 26: Renewal priority setting unit

Claims

1. A pipeline renewal plan formulation system for formulating renewal plans for each pipeline constituting a pipeline network according to calculations performed by a processor, comprising: a pipeline data acquisition unit that acquires pipeline data constituting the pipeline network necessary for formulating a pipeline renewal plan; a leakage accident rate calculation unit that calculates a predicted value of the leakage accident rate [incidents / year / km] for each pipeline at a predetermined time; a hydraulic analysis unit that performs a hydraulic analysis of the pipeline network based on the pipeline data; a pipeline outage estimation unit that activates the hydraulic analysis unit under the assumption that a leakage accident has occurred in a specific pipeline based on predetermined conditions, and repeats the process of estimating the pipeline that will experience a water outage based on the results of the hydraulic analysis for different specific pipelines; a water outage impact calculation unit that calculates the degree of water outage impact by each pipeline that will experience a water outage estimated by the water outage estimation unit; and a renewal priority setting unit that sets the renewal priority for the specific pipelines based on the degree of water outage impact calculated by the water outage impact calculation unit.

2. The pipeline renewal planning system according to claim 1, wherein the pipeline estimation unit for water outages estimates pipelines where the water pressure falls below a standard value based on the results of the hydraulic analysis to be pipelines where water outages are likely to occur.

3. The pipeline renewal planning system according to claim 2, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the population affected by the water outage [people / incident] obtained by dividing the amount of water out of the pipeline where the water outage occurred by the amount of water used per person.

4. The pipeline renewal planning system according to claim 2, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the number of households affected by the water outage [households / incident] obtained by dividing the amount of water out of the pipeline where the water outage occurred by the amount of water used per household.

5. The pipeline renewal planning system according to claim 2, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is the total number of water supply pipes connected to the pipeline where the water outage occurred.

6. The pipeline renewal planning system according to any one of claims 3 to 5, wherein the impact of water outages is determined by taking into account the probability of water outages occurring for each pipeline due to water leakage accidents, obtained from cumulative data of past water leakage accidents.

7. The pipeline renewal planning system according to any one of claims 3 to 5, wherein the impact of the water outage takes into account the number of days required to restore each pipeline in response to a water leakage accident.

8. A pipeline renewal plan formulation method for formulating renewal plans for each pipeline constituting a pipeline network according to calculation processing by a processor, comprising: a pipeline data acquisition step for acquiring pipeline data constituting the pipeline network necessary for formulating a pipeline renewal plan; a leakage accident rate calculation step for calculating a predicted value of the leakage accident rate [incidents / year / km] at a predetermined time for each pipeline; a hydraulic analysis step for performing a hydraulic analysis of the pipeline network based on the pipeline data; a water outage occurrence pipeline estimation step for performing the hydraulic analysis step under the assumption that a leakage accident has occurred in a specific pipeline based on predetermined conditions, and repeating the process of estimating the pipeline that will experience a water outage based on the results of the hydraulic analysis for different specific pipelines; a water outage impact calculation step for calculating the degree of water outage impact by each water outage occurrence pipeline estimated in the water outage occurrence pipeline estimation step; and a renewal priority setting step for setting the renewal priority for the specific pipelines based on the degree of water outage impact calculated in the water outage impact calculation step.

9. The pipeline renewal plan formulation method according to claim 8, wherein the step of estimating pipelines where water outages occur is to estimate that pipelines where the water pressure is below a standard value are the pipelines where water outages occur, based on the results of the hydraulic analysis.

10. The pipeline renewal plan formulation method according to claim 9, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the population affected by the water outage [people / incident] obtained by dividing the amount of water out of the pipeline where the water outage occurred by the amount of water used per person.

11. The method for formulating a pipeline renewal plan according to claim 9, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the number of households affected by the water outage [households / incident] obtained by dividing the amount of water out of the pipeline where the water outage occurred by the amount of water used per household.

12. The method for formulating a pipeline renewal plan according to claim 9, wherein the degree of impact of the water outage is expressed as the product of the estimated value of the water leakage accident rate [incidents / year / km], the pipeline length of the pipeline in question [km], and the number of households affected by the water outage [households / incident], which is the total number of water supply pipes connected to the pipeline where the water outage occurred.

13. The pipeline replacement plan formulation method according to any one of claims 10 to 12, wherein the impact of water outages is taken into account the probability of water outages occurring for each pipeline due to water leakage accidents obtained from cumulative data of past water leakage accidents.

14. The method for formulating a pipeline replacement plan according to any one of claims 10 to 12, wherein the impact of the water outage is taken into account the number of days required to restore water leaks for each pipeline.

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