Water supply pipe network optimization design method based on control path hierarchical optimization

Abstract

The invention discloses a water supply pipe network optimization design method based on control path hierarchical optimization. The method comprises the steps that an annular water supply pipe network model is converted into a branch-shaped water supply pipe network model; determining the initial pipe diameter of each pipe section in the water supply pipe network according to the lowest economic flow velocity; finding out a water supply pipe network control point and a main control path; solving an optimal pipe diameter scheme of a main control path by taking reduction of a total cost finance net present value of the whole life cycle of the water supply pipe network as a target; reducing the finance net present value of the construction cost of the water supply network as a target, optimizing the pipe diameter of each branch control path by using the surplus water head of each branch control path after the pipe diameter of the main control path is optimized, and solving the optimal pipe diameter scheme of each branch control path; and carrying out adjustment calculation on the water supply network, judging whether the pipe diameter scheme of the water supply network meets the requirements of the three most unfavorable working conditions, and determining a final pipe diameter optimization design scheme of the water supply network according to a judgment result. The method is high in efficiency, and the deficiency of human experience can be avoided.

Description

Technical Field

[0001] The present application relates to a water supply network optimization design method, and specifically to a water supply network optimization design method based on control path hierarchical optimization. Background Art

[0002] The urban water supply network is an important part of the urban drinking water project. With the continuous expansion of the water supply network and the increase of long-distance water transmission and distribution projects, the proportion of the water supply network cost in the entire water supply system is increasing, generally 50% to 80% of the total investment of the entire project. The planning and design of the water supply network directly affects the project investment and operation and management costs. Reasonable optimization of the design of the water supply network is of great significance for saving project investment, reducing operating costs, ensuring system safety, improving service quality, and improving the economic and social benefits of the project.

[0003] The traditional water supply network design method is based on the "Outdoor Water Supply Design Standard" GB 50013-2018, "Urban Water Supply Engineering Planning Code" GB 50282-2016 and other specifications. Designers first set the pipe diameter based on experience according to the primary and secondary relationships of the pipe sections, and then calculate the flow of each pipe section according to the highest daily water consumption within the design life. The pipe diameter is further determined based on the economic flow rate according to the flow of each pipe section. On this basis, the pipe diameter and water pump head are determined through leveling calculations, and then the system is checked to see whether it can meet the water volume and water pressure requirements under the following three water use conditions: 1. When the most unfavorable pipe section fails; 2. During firefighting; 3. During maximum transfer (when there is a water tower in the water supply network).

[0004] The traditional design method mainly relies on experience to design each pipe section, without considering the rationality and cost savings of the water supply network diameter selection from an overall perspective. Due to the differences in the levels of different designers, the design plan may need to be modified many times during the design process, which consumes a lot of manpower costs and has certain limitations. The result is not the optimal solution and there is often a lot of room for optimization.

[0005] Among the existing water supply network design methods, some methods use intelligent algorithms to optimize pipe diameters. They often use the cost of the water supply network as the objective function, the diameter of each pipe section as the decision variable, and combine the continuity equation, energy equation and other constraints of the water supply network to solve the problem. The intelligent optimization algorithms commonly used to solve such optimization problems include genetic algorithms, particle swarm algorithms, and ant colony algorithms, but they have their own shortcomings and it is difficult to obtain a stable optimal solution.

[0006] Through the above analysis, we can know that the current water supply network design method has the following problems in actual operation:

[0007] (1) Designers usually select pipe diameters based on experience. The pipe diameter selected according to the economic flow rate can only ensure the optimality of a single pipe diameter, but cannot ensure the optimality of the water supply network as a whole. The selection of pipe diameters is highly artificial, and the relationship between pipe diameters and the cost of the water supply network and the operating power costs is not considered as a whole. It is often difficult to ensure the economic optimality of the water supply network design.

[0008] (2) The optimization method using intelligent algorithms has a large amount of calculation and slow convergence speed. In addition, there are problems such as unstable results, easy to fall into local optimal solutions, the pipe diameter obtained does not conform to the actual situation, and slow convergence speed. These problems lead to low optimization efficiency of the water supply network and difficulty in obtaining the optimal solution. Summary of the invention

[0009] The present invention provides a water supply network optimization design method based on control path hierarchical optimization, which has high efficiency and can avoid the deficiency of human experience.

[0010] The technical solution provided by the present invention is:

[0011] In a first aspect, the present application provides a water supply network optimization design method based on control path hierarchical optimization, comprising:

[0012] S1. Establish a hydraulic model of the water supply network;

[0013] S2. Based on the hydraulic model of the water supply network, find the shortest distance path set P from each node of the water supply network to the water plant;

[0014] S3. The pipe segments in the water supply network that are not covered by the shortest path set P are defined as set Q; for each pipe segment in set Q, the demarcation points are found respectively, and each pipe segment is disconnected at the demarcation points, and the pipes at both ends of the demarcation points are connected to the nodes at both ends of the pipe segment respectively, thereby converting the ring water supply network model into a branch water supply network model;

[0015] S4, distributing the flow rate to each pipe section in the water supply network based on the branched water supply network model;

[0016] S5. According to the flow rate allocated to each pipe section in the water supply network, determine the maximum pipe diameter of each pipe section in the water supply network according to the minimum economic flow rate, and adjust the initial pipe diameter of each pipe section in the water supply network to the engineering pipe diameter that is closest to it in the standard pipe diameter set and is less than or equal to the maximum pipe diameter in the standard pipe diameter set;

[0017] S6. Based on the initial diameter of each pipe section in the water supply network, perform water supply network adjustment calculation to find the point with the lowest free water head in the water supply network as the control point; find the shortest path from the control point to the water plant as the main control path of the water supply network;

[0018] S7. To reduce the total cost of the water supply network over its entire life cycle, the optimal pipe diameter solution for the main control path is solved;

[0019] S8, determining branch control paths at all levels of the main control path;

[0020] S9, with the goal of reducing the financial net present value of the construction cost of the water supply network, and using the surplus water head of each branch control path after the pipe diameter of the main control path is optimized, the pipe diameter of each branch control path is optimized, and the optimal pipe diameter solution of each branch control path is solved;

[0021] S10. According to the optimal pipe diameter scheme of the main control path and the optimal pipe diameter scheme of each level of branch control paths, the water supply network adjustment calculation is performed to determine whether the water supply network meets the requirements of the most unfavorable working conditions, and the final water supply network diameter optimization design scheme is determined based on the judgment result.

[0022] In a possible implementation, in step S3, finding the demarcation point of each pipe segment in the set Q includes:

[0023] For each pipe segment in set Q, use the Floyd algorithm to find a point where the shortest distance from the pipe segment on one side to the water plant (water source) is equal to the shortest distance from the pipe segment on the other side to the water plant. This point is defined as the dividing point.

[0024] In a possible implementation, step S7 includes:

[0025] S7.1. Initialization t 0 =1;

[0026] S7.2. Perform the t 0 Wheel optimization:

[0027] S7.2.1. Determine N alternative solutions, where each alternative solution is a pipe diameter of a pipe section on the main control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specification in the standard pipe diameter set; where N is the number of pipe sections on the main control path;

[0028] S7.2.2, for each alternative plan, carry out water supply network adjustment calculation;

[0029] S7.2.3, based on the adjustment calculation results, respectively solve the change ΔFNPV of the total financial net present value (FNPV) of the water supply network cost after the implementation of each alternative plan;

[0030] S7.2.4. Based on ΔFNPV, determine whether there is an alternative plan that can reduce the financial net present value of the total cost of the water supply network. If not, end the optimization of each pipe section on the main control path, and use the current pipe diameter plan of each pipe section on the main control path as the optimal pipe diameter plan of the main control path; if it exists, select the alternative plan that can reduce the financial net present value of the total cost of the water supply network the most as the optimization plan for this round, and update the pipe diameter of the corresponding pipe section according to the optimization plan for this round;

[0031] S7.2.5, let t 0 =t 0 +1, return to step S7.2.

[0032] In a possible implementation, in step S7.2.3, the first alternative corresponds to the jth reduction in diameter of the i-th pipe section on the main control path of the water supply network, i = 1, 2, ..., N; then the change in the total financial net present value of the water supply network cost after the first alternative is executed ΔFNPV ij for:

[0033] ΔFNPV ij =ΔFNPV Oij +ΔFNPV Cij

[0034] ΔFNPV Cij =c(D' ij )·l i -c(D ij )·l i

[0035]

[0036] Where, ΔFNPV Oij The net financial present value of the increased operating cost of the water supply network after the implementation of the first alternative is positive; ΔFNPV Cij is the financial net present value of the reduced construction cost of the water supply network after the implementation of the first alternative plan, and its value is negative; D ij is the diameter of the i-th pipe section on the main control path before the first alternative is executed, D' ij is the diameter of the i-th pipe section on the main control path after the first alternative is executed, c(D ij ) is the unit length cost of the i-th pipe section on the main control path before the first alternative is executed, c(D' ij ) is the unit length cost of the i-th pipe section on the main control path after the first alternative is executed, l i is the length of the i-th pipe section on the main control path; a' ij is the annual operating cost of the water supply network after the implementation of the first alternative, a ijis the annual operating cost of the water supply network before the implementation of the first alternative, where a' ij and a ij It is related to the adjustment calculation result of the water supply network under the corresponding pipe diameter scheme. FIRR is the financial internal rate of return (%) of the enterprise. FIRR is determined by the enterprise, and y is the construction period.

[0037] In a possible implementation, step S8 includes:

[0038] Let the node on the main control path be the root node;

[0039] Find the point with the smallest free water head in the branch connected to each root node respectively as the first-level branch control point; take the shortest path from each first-level branch control point to the corresponding root node as the first-level branch control path; take the nodes on the first-level branch control path as the first-level branch nodes;

[0040] By analogy, find the points with the smallest free water head in the branches connected to each r-th level branch node as the r+1-th level branch control point; take the shortest path from each r+1-th level branch control point to the corresponding r-th level branch node as the r+1-th level branch control path; take the nodes on the r+1-th level branch control path as the r+1-th level branch node; where r = 1, 2, ..., R-1, and the R-th level branch node is a leaf node in the branched water supply network model;

[0041] Thus, the water supply network is determined from the 1st level branch control path to the Rth level branch control path.

[0042] In some possible implementations, step S9 includes:

[0043] S9.1, initialize r=1;

[0044] S9.2. Calculate the optimal pipe diameter solution for the r-th level branch control path:

[0045] S9.2.1. Initialization t r =1;

[0046] S9.2.2. Determine the t r M alternatives for round optimization, where each alternative is a pipe diameter of an r-th level branch control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specifications in the standard pipe diameter set. If the minimum pipe diameter in the standard pipe diameter set is reached, it will not be reduced any further (e.g., the minimum pipe diameter of a municipal pipeline is DN100); where M is the number of r-th level branch control paths;

[0047] S9.2.3, respectively solve the financial net present value of the reduced construction cost and the increased head loss Δh after the implementation of each alternative plan;

[0048] S9.2.4. Compare the increased head loss Δh after the implementation of each alternative solution with the surplus head H of the corresponding r-th level branch before the implementation of the corresponding alternative solution; determine whether there is an alternative solution with a corresponding Δh < H; if not, end the optimization of the r-th level branch control path, take the current pipe diameter plan of the r-th level branch control path as the optimal pipe diameter plan of the r-th level branch control path, and go to step S9.2.6; if so, select the plan with the largest net present value of the reduced construction cost among all alternative solutions with Δh < H as the optimal plan for the t r -th round, implement this plan, that is, update the pipe diameter according to this plan, and go to step S9.2.5;

[0049] S9.2.5. Let t r = t r + 1, and return to step S9.2.2;

[0050] S9.2.6. Let r = r + 1, and return to step S9.2.

[0051] In some possible implementation manners, the step S10 includes: according to the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level branch control path, perform hydraulic network adjustment calculation, determine whether the water supply network meets the water consumption and pressure requirements under the three most unfavorable working conditions of the occurrence of a failure in the most unfavorable pipe section, during fire fighting, and during maximum transmission, and determine the final optimized design plan of the water supply network pipe diameter according to the judgment result.

[0052] In some possible implementation manners, the determining the final optimized design plan of the water supply network pipe diameter according to the judgment result includes: if it is satisfied, take the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level branch control path as the final optimized design plan of the water supply network pipe diameter; if the requirements are not met, consider making fine adjustments to the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level branch control path, such as changing the front section of the main control path to a double pipe, and finally determine the engineering plan of the water supply network pipe diameter close to the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level branch control path as the final optimized design plan of the water supply network pipe diameter.

[0053] In a third aspect, the present application provides an electronic device, including: a memory and a processor;

[0054] The memory is used to store a computer program;

[0055] The processor is used to call the computer program to execute the method as described above.

[0056] In a fourth aspect, the present application provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed on an electronic device, the electronic device implements the method described above.

[0057] In a fifth aspect, the present application provides a computer program product, including a computer program, and when the computer program is run on an electronic device, the electronic device implements the method as described above.

[0058] The specific implementation methods of the second to fifth aspects of the present application can refer to the implementation methods of the first aspect, which will not be repeated here.

[0059] Beneficial effects:

[0060] Compared with the existing water supply network design method, this application has the following advantages:

[0061] (1) Compared with traditional design methods, it does not rely on the design experience of engineering designers, avoids the lack of human experience, and can systematically obtain the optimal solution for the water supply network combination, which is convenient for decision-making.

[0062] (2) Compared with some existing methods that use algorithms to optimize the design of water supply networks, this method has a reliable theoretical basis and does not require multiple iterative solutions of complex algorithms. Therefore, it does not have the problems of slow convergence, easy to fall into local optimal solutions, and poor result stability of these algorithms. It has fast convergence speed and high efficiency.

[0063] (3) This method can be applied to the optimization design of newly built water supply networks. The method is highly operational and can quickly determine the diameters of each pipe section in the water supply network, thereby improving the design efficiency of the water supply network. At the same time, it takes into account the overall operating costs of the water supply network and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] Figure 1 This is a flow chart of an embodiment of the present application. DETAILED DESCRIPTION

[0065] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application.

[0066] It should be noted that the terms such as "first" and "second" in the specification and claims of this application and the above-mentioned drawings are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply a specific relationship or order between these entities or operations. It should be understood that the words "first" and "second" do not limit the quantity and execution order, and the words "first" and "second" do not necessarily limit them to be different. It should be understood that the data used in this way can be interchangeable under appropriate circumstances.

[0067] The embodiment of the present application adopts the idea of ​​hierarchical optimization based on the control path, and optimizes the control path in a hierarchical manner until the optimal combination of the diameters of all pipe sections is determined. When solving the optimal diameter scheme of the main control path, the goal is to reduce the total financial net present value of the entire life cycle of the water supply network. In each round, the diameters of multiple pipe sections are changed, and an acceptable engineering scheme is selected for optimization, so that the total cost is quickly reduced and the convergence speed is significantly improved; the embodiment of the present application determines the optimal diameter scheme of the branch control paths at all levels of the main control path, with the goal of reducing the financial net present value of the construction cost of the water supply network. At the same time, the surplus water head of each branch control path after the diameter optimization of the main control path is fully utilized to optimize the diameter of each branch control path. Reducing the diameter of each branch path can improve water delivery efficiency, reduce energy consumption and engineering costs, reduce the design head of the pump, and obtain a diameter optimization scheme with a total financial net present value FNPV of the water supply network close to the minimum, and a stable optimization solution can be found in a shorter time.

[0068] The following will refer to Figure 1 Specific embodiments according to the present application are described.

[0069] The present application embodiment discloses a water supply network optimization design method based on control path hierarchical optimization, including:

[0070] S1. Establish a hydraulic model of the water supply network;

[0071] A hydraulic model of the water supply network is established based on the water supply network topology and basic parameters, including terrain information, water plant information (water plant location, elevation, flow, pressure, etc.), node information (node ​​number, location, elevation, flow, etc.) and pipe section information (pipe section number, location, length, material, etc.).

[0072] S2. Based on the hydraulic model of the water supply network, find the shortest distance path set P from each node of the water supply network to the water plant;

[0073] In some embodiments, the shortest distance from each node of the water supply network to the water plant is calculated by the Floyd algorithm for calculating the shortest distance, and the shortest path set P is obtained. The Floyd algorithm is a classic algorithm for calculating the shortest path between two points in solving graph theory problems, and is applicable to graphs with dense nodes. The specific steps are as follows:

[0074] 1) Start from any single-edge path. The distance between all two points is the weight of the edge. If there is no edge connecting two points, the weight is infinite.

[0075] 2) For each pair of vertices u and v, see if there is a vertex w (usually called an intermediate point) such that the path from u to w and then to v is shorter than the known path. If so, update it.

[0076] 3) Traverse until the end, at this time the data structure storing the graph has obtained the multi-source shortest path.

[0077] S3. The pipe segments in the water supply network that are not covered by the shortest path set P are defined as a set Q; for each pipe segment in the set Q, the demarcation points are found respectively, and each pipe segment is disconnected at the demarcation points, and the pipes at both ends of the demarcation points are connected to the nodes at both ends of the pipe segment respectively, thereby converting the ring water supply network model into a branch water supply network model (converting the calculation model of the ring network into the calculation model of the branch network);

[0078] In some embodiments, for each pipe segment in the set Q, finding its demarcation point respectively includes:

[0079] For each pipe segment in set Q, use the Floyd algorithm to find a point where the shortest distance from the pipe segment on one side to the water plant (water source) is equal to the shortest distance from the dividing point to the water plant on the other side. This point is defined as the dividing point.

[0080] S4, distributing the flow rate to each pipe section in the water supply network based on the branched water supply network model;

[0081] The flow of the water supply network can be distributed according to the length or area of ​​the pipe, where each pipe section in the set Q is disconnected into two nodes at the dividing point a k 、b k (k = 1, 2, ..., K, K is the number of pipe sections in the set Q), the flow is distributed to a by the pipe sections at both ends of the dividing point k 、b k .

[0082] S5. According to the flow rate allocated to each pipe section in the water supply network, determine the maximum pipe diameter of each pipe section in the water supply network according to the minimum economic flow rate, and adjust the initial pipe diameter of each pipe section in the water supply network to the engineering pipe diameter that is closest to it in the standard pipe diameter set and is less than or equal to the maximum pipe diameter in the standard pipe diameter set;

[0083] Among them, the maximum diameter of each pipe section is determined according to the minimum economic flow rate, and the formula is:

[0084]

[0085] Where D i，max is the maximum diameter of pipe section i in the water supply network, Q i The flow rate allocated to pipe section i (m 3 / s), v min It is the minimum economic flow rate of the pipe section, generally 0.6m / s.

[0086] D i ∈{D},i=1,2,…,N 1

[0087] Where D i is the diameter of pipe section i, {D} is the set of standard pipe diameters, N 1 is the number of pipe sections in the water supply network.

[0088] Among them, determining the maximum pipe diameter of each pipe section in the water supply network according to the flow rate allocated to each pipe section in the water supply network according to the minimum economic flow rate can prevent siltation in the pipe.

[0089] S6. Based on the initial diameter of each pipe section in the water supply network, perform water supply network adjustment calculation to find the point with the lowest free water head in the water supply network as the control point; find the shortest path from the control point to the water plant as the main control path of the water supply network;

[0090] In some embodiments, finding the shortest path from the control point to the water plant includes: taking the control point as the starting point and the water plant as the end point, and using the Floyd algorithm to find the shortest path from the control point to the water plant in the reverse direction of the water flow.

[0091] S7. To reduce the total cost of the water supply network over its entire life cycle, the optimal pipe diameter solution for the main control path is solved;

[0092] In some embodiments, the basic parameters such as the material, specification, cost, friction, and financial internal rate of return (FIRR) of each pipeline are used as the initial conditions of the water supply network, and the goal is to reduce the total cost financial net present value (FNPV) of the water supply network over its entire life cycle. The pressure at the starting point of the water supply network (the outlet of the water plant) and the diameter of each pipe section can be changed, and the optimal pipe diameter solution of the main control path is solved by the following algorithm:

[0093] S7.1. Initialization t 0 =1;

[0094] S7.2. Perform the t0 Wheel optimization:

[0095] S7.2.1. Determine N alternative solutions, where each alternative solution is a pipe diameter of a pipe section on the main control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specification in the standard pipe diameter set; where N is the number of pipe sections on the main control path;

[0096] S7.2.2, for each alternative plan, carry out water supply network adjustment calculation;

[0097] Among them, the constraints of adjustment calculation are:

[0098] 1) Node pressure constraint: Municipal water supply must guarantee the water pressure requirements of users. The free water pressure of all nodes must meet the local minimum service head, such as 28m, that is, H i ≥H min ;

[0099] 2) Energy conservation equation: In a ring-shaped water supply network, the sum of the head losses of all pipe sections in each ring (including virtual rings) must be 0, that is, Lh = 0;

[0100] 3) Node continuity equation: For any node in the water supply network, the flow to the node and the flow out of the node must be equal, that is, Aq+Q=0;

[0101] 4) Pressure drop equation: The head loss of each pipe section is the difference in head between the two nodes of the pipe section, satisfying h = sq m , m=1.852~2, depending on the head formula.

[0102] Where A——connection matrix (connection matrix);

[0103] q——the flow rate of the pipe section of the water supply network, m 3 / s;

[0104] Q——Node flow of water supply network, m 3 / s;

[0105] L——loop matrix;

[0106] h——head loss of water supply network, m;

[0107] s——friction coefficient;

[0108] H i , H min ——Actual water pressure and minimum water pressure at node i, m.

[0109] S7.2.3, based on the adjustment calculation results, calculate the change in the total financial net present value of the water supply network cost after the implementation of each alternative plan, ΔFNPV;

[0110] Assume that the first alternative corresponds to the jth reduction in diameter of the i-th pipe section on the main control path of the water supply network, i = 1, 2, ..., N; then the change in the total financial net present value of the water supply network cost after the first alternative is implemented ΔFNPV ij for:

[0111] ΔFNPV ij =ΔFNPV Oij +ΔFNPV Cij

[0112] ΔFNPV Cij =c(D' ij )·l i -c(D ij )·l i

[0113]

[0114] Where, ΔFNPV Oij ΔFNPV is the financial net present value of the additional operating cost of the water supply network after the implementation of the first alternative plan, in yuan, and its value is positive; Cij is the financial net present value of the reduced construction cost of the water supply network after the implementation of the first alternative plan, in yuan, and its value is negative; D ij The diameter of the i-th pipe section on the main control path before the first alternative is executed, in meters, D' ij is the diameter of the i-th pipe section on the main control path after the first alternative is executed, in m, c(D ij ) is the unit length cost of the i-th pipe section on the main control path before the first alternative is executed, in yuan, c(D' ij ) is the unit length cost of the i-th pipe section on the main control path after the first alternative is executed, in yuan, l i The length of the i-th pipe section on the main control path, in m; a' ij is the annual operating cost of the water supply network after the implementation of the first alternative plan, in yuan, a ij is the annual operating cost of the water supply network before the implementation of the first alternative, in yuan, where a' ij and a ij It is related to the adjustment calculation result of the water supply network under the corresponding pipe diameter scheme. FIRR is the financial internal rate of return (%) of the enterprise. FIRR is determined by the enterprise, and y is the construction period.

[0115] It should be understood that as the pipe diameter decreases, the construction cost of the water supply network will decrease. However, because the pipe diameter becomes smaller, the head loss will increase. In order to ensure that the head at the control point still meets the minimum free head, the water plant's pump head (water supply pressure) needs to be increased, so the operating cost of the entire network will increase.

[0116] S7.2.4, based on ΔFNPV, determine whether there is an alternative plan that reduces the financial net present value of the total cost of the water supply network after execution; if not, end the optimization of each pipe section on the main control path, and use the current pipe diameter plan of each pipe section on the main control path as the optimal pipe diameter plan of the main control path; if it exists, select the alternative plan that can reduce the financial net present value of the total cost of the water supply network the most as the optimization plan for this round, and update the pipe diameter of the corresponding pipe section according to the optimization plan for this round;

[0117] In this step, based on ΔFNPV, it is determined whether there is an alternative plan that can reduce the total financial net present value of the water supply network cost after implementation, that is, to determine ΔFNPV ij , i=1,2,…,whether there is a value less than 0 in N, that is, whether there is a certain alternative plan or some alternative plans, the reduced construction cost is greater than the increased operating cost. If so, the corresponding ΔFNPV is executed ij ,i∈1,2,…,N} the smallest alternative (i.e., executing the corresponding ΔFNPV ij <0 and with the largest absolute value, update the diameter of the corresponding pipe section).

[0118] S7.2.5, let t 0 =t 0 +1, return to step S7.2.

[0119] During the pipe diameter optimization process of the main control path, it is necessary to recalculate the water supply network leveling. Based on the leveling calculation results, the water plant's pump head and the free water head of each node in the network can be determined. Since the diameter of a certain pipe section is reduced during the pipe diameter optimization process of the main control path, the head loss of the pipe section will increase. In order to meet the minimum service head requirements of the network nodes, the water plant's pump head will be increased. At this time, except for the control points, there will be surplus head increases at other nodes. The subsequent steps of the embodiment of the present application optimize the branch control paths of each level of the main control path based on the surplus head.

[0120] S8, determining branch control paths at all levels of the main control path;

[0121] In some embodiments, determining each level of branch control paths of the main control path may include:

[0122] Let the node on the main control path be the root node;

[0123] Find the point with the smallest free water head in the branch connected to each root node respectively as the first-level branch control point; take the shortest path from each first-level branch control point to the corresponding root node as the first-level branch control path; take the nodes on the first-level branch control path as the first-level branch nodes;

[0124] By analogy, find the points with the smallest free water head in the branches connected to each r-th level branch node as the r+1-th level branch control point; take the shortest path from each r+1-th level branch control point to the corresponding r-th level branch node as the r+1-th level branch control path; take the nodes on the r+1-th level branch control path as the r+1-th level branch node; where r = 1, 2, ..., R-1, and the R-th level branch node is a leaf node in the branched water supply network model;

[0125] Thus, the water supply network can be determined from the 1st level branch control path to the Rth level branch control path;

[0126] S9, with the goal of reducing the financial net present value of the construction cost of the water supply network, and using the surplus water head of each branch control path after the pipe diameter of the main control path is optimized, the pipe diameter of each branch control path is optimized, and the optimal pipe diameter solution of each branch control path is solved;

[0127] In some embodiments, this step includes:

[0128] S9.1, initialize r=1;

[0129] S9.2. Calculate the optimal pipe diameter solution for the r-th level branch control path:

[0130] S9.2.1. Initialization t r =1;

[0131] S9.2.2. Determine the t r M alternatives for round optimization, where each alternative is a pipe diameter of an r-th level branch control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specifications in the standard pipe diameter set. If the minimum pipe diameter in the standard pipe diameter set is reached, it will not be reduced any further (e.g., the minimum pipe diameter of a municipal pipeline is DN100); where M is the number of r-th level branch control paths;

[0132] S9.2.3, respectively solve the financial net present value of the reduced construction cost and the increased head loss Δh after the implementation of each alternative plan;

[0133] S9.2.4. Compare the increased head loss Δh after the implementation of each alternative solution with the surplus head H of the corresponding r-th level branch before the implementation of the corresponding alternative solution; determine whether there is an alternative solution with a corresponding Δh < H; if not, end the optimization of the r-th level branch control path, take the current pipe diameter plan of the r-th level branch control path as the optimal pipe diameter plan of the r-th level branch control path, and go to step S9.2.6; if so, select the plan with the largest net present value of the construction cost reduction among all alternative solutions with Δh < H as the optimal plan for the t r round, implement this plan, that is, update the pipe diameter according to this plan, and go to step S9.2.5;

[0134] S9.2.5. Let t r = t r + 1, and return to step S9.2.2;

[0135] S9.2.6. Let r = r + 1, and return to step S9.2;

[0136] S10. According to the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level of branch control paths, perform a hydraulic analysis of the water supply network to determine whether the water supply network meets the requirements of the most unfavorable working conditions, and determine the final optimized design plan for the pipe diameter of the water supply network according to the judgment result.

[0137] In some embodiments, step S10 includes: according to the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level of branch control paths, perform a hydraulic analysis of the water supply network to determine whether the water supply network meets the water consumption and pressure requirements under the three most unfavorable working conditions of when the most unfavorable pipe section fails, during fire fighting, and during maximum transmission (when there is a water tower in the water supply network), and determine the final optimized design plan for the pipe diameter of the water supply network according to the judgment result.

[0138] In some embodiments, determining the final optimized design plan for the pipe diameter of the water supply network according to the judgment result includes: if it is satisfied, take the optimal pipe diameter plan of the main control path and the optimal pipe diameter plans of each level of branch control paths as the final optimized design plan for the pipe diameter of the water supply network; if it does not meet the requirements, consider making fine adjustments to the above optimal pipe diameter plan, such as changing the front section of the main control path to a double pipe, and finally determine the engineering plan with the pipe diameter of the water supply network close to the optimal pipe diameter plan as the final optimized design plan for the pipe diameter of the water supply network.

[0139] The embodiments of the present application also provide an electronic device, including: a memory and a processor;

[0140] The memory is used to store a computer program;

[0141] The processor is used to call the computer program to execute the method as described above.

[0142] An embodiment of the present application further provides a computer-readable storage medium, in which a computer program is stored. When the computer program is executed on an electronic device, the electronic device implements the method as described above.

[0143] An embodiment of the present application further provides a computer program product, including a computer program. When the computer program is executed on an electronic device, the electronic device implements the method as described above.

[0144] The embodiments of the present application also provide a system, an electronic device, a computer-readable storage medium, and a computer program product. The specific implementation methods can refer to the specific embodiments of the above methods and will not be repeated here.

[0145] Obviously, those skilled in the art should understand that the above-mentioned units or steps of the present application can be implemented by a general-purpose computing device, they can be concentrated on a single computing device, or distributed on a network composed of multiple computing devices, and optionally, they can be implemented by a program code executable by a computing device, so that they can be stored in a storage device and executed by the computing device, or they can be made into individual integrated circuit modules, or multiple modules or steps therein can be made into a single integrated circuit module for implementation. In this way, the present application is not limited to any specific combination of hardware and software.

[0146] The above description of the embodiments of the present application is only a partial embodiment of the present application, which is used to enable professionals in the field to implement or use the content of the present application, and is not used to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application should be included in the protection scope of the present application.

Claims

1. A water supply network optimization design method based on control path hierarchical optimization, characterized in that: include: S1. Establish a hydraulic model of the water supply network; S2. Based on the hydraulic model of the water supply network, find the shortest distance path set P from each node of the water supply network to the water plant; S3. The pipe segments in the water supply network that are not covered by the shortest path set P are defined as set Q; for each pipe segment in set Q, the demarcation points are found respectively, and each pipe segment is disconnected at the demarcation points, and the pipes at both ends of the demarcation points are connected to the nodes at both ends of the pipe segment respectively, thereby converting the ring water supply network model into a branch water supply network model; S4, distributing the flow rate to each pipe section in the water supply network based on the branched water supply network model; S5. According to the flow rate allocated to each pipe section in the water supply network, determine the maximum pipe diameter of each pipe section in the water supply network according to the minimum economic flow rate, and adjust the initial pipe diameter of each pipe section in the water supply network to the engineering pipe diameter that is closest to it in the standard pipe diameter set and is less than or equal to the maximum pipe diameter in the standard pipe diameter set; S6. Based on the initial diameters of each pipe section in the water supply network, perform water supply network adjustment calculation to find the point with the lowest free water head in the water supply network as the control point; Find the shortest path from the control point to the water plant as the main control path of the water supply network; S7. To reduce the total cost of the water supply network over its entire life cycle, the optimal pipe diameter solution for the main control path is solved; S8, determining branch control paths at all levels of the main control path; S9, with the goal of reducing the financial net present value of the construction cost of the water supply network, and using the surplus water head of each branch control path after the pipe diameter of the main control path is optimized, the pipe diameter of each branch control path is optimized, and the optimal pipe diameter solution of each branch control path is solved; S10. According to the optimal pipe diameter scheme of the main control path and the optimal pipe diameter scheme of each level of branch control paths, the water supply network adjustment calculation is performed to determine whether the water supply network meets the requirements of the most unfavorable working conditions, and the final water supply network diameter optimization design scheme is determined based on the judgment result.

2. The method according to claim 1, characterized in that In step S3, for each pipe segment in the set Q, finding its demarcation point respectively includes: For each pipe segment in set Q, use the Floyd algorithm to find a point where the shortest distance from the pipe segment on one side to the water plant (water source) is equal to the shortest distance from the pipe segment on the other side to the water plant. This point is defined as the dividing point.

3. The method according to claim 1, characterized in that: The step S7 comprises: S7.1, initialization t0=1; S7.2, perform the t0th round of optimization: S7.2.

1. Determine N alternative solutions, where each alternative solution is a pipe diameter of a pipe section on the main control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specification in the standard pipe diameter set; where N is the number of pipe sections on the main control path; S7.2.2, for each alternative plan, carry out water supply network adjustment calculation; S7.2.3, based on the adjustment calculation results, calculate the change in the total financial net present value of the water supply network cost after the implementation of each alternative plan, ΔFNPV; S7.2.

4. Based on ΔFNPV, determine whether there is an alternative plan that can reduce the financial net present value of the total cost of the water supply network. If not, end the optimization of each pipe section on the main control path, and use the current pipe diameter plan of each pipe section on the main control path as the optimal pipe diameter plan of the main control path; if it exists, select the alternative plan that can reduce the financial net present value of the total cost of the water supply network the most as the optimization plan for this round, and update the pipe diameter of the corresponding pipe section according to the optimization plan for this round; S7.2.

5. Let t0=t0+1, and return to step S7.

2.

4. The method according to claim 1, characterized in that: In step S7.2.3, assume that the first alternative solution corresponds to the jth reduction in diameter of the i-th pipe section on the main control path of the water supply network, i = 1, 2, ..., N; then the change in the total financial net present value of the water supply network cost after the first alternative solution is executed ΔFNPV ij for: ΔFNPV ij =ΔFNPV Oij +ΔFNPV Cij ΔFNPV Cij =c(D’ ij )·l i -c(D ij )·l i Where, ΔFNPV Oij The net financial present value of the increased operating cost of the water supply network after the implementation of the first alternative is positive; ΔFNPV Cij is the financial net present value of the reduced construction cost of the water supply network after the implementation of the first alternative plan, and its value is negative; D ij is the diameter of the i-th pipe section on the main control path before the first alternative is executed, D' ij is the diameter of the i-th pipe section on the main control path after the first alternative is executed, c(D ij ) is the unit length cost of the i-th pipe section on the main control path before the first alternative is executed, c(D' ij ) is the unit length cost of the i-th pipe section on the main control path after the first alternative is executed, l i is the length of the i-th pipe section on the main control path; a' ij is the annual operating cost of the water supply network after the implementation of the first alternative, a ij is the annual operating cost of the water supply network before the implementation of the first alternative, where a' ij and a ij It is related to the adjustment calculation result of the water supply network under the corresponding pipe diameter scheme. FIRR is the financial internal rate of return of the enterprise. FIRR is determined by the enterprise, and y is the construction period.

5. The method according to claim 1, characterized in that The step S8 comprises: Let the node on the main control path be the root node; Find the point with the smallest free water head in the branch connected to each root node respectively as the first-level branch control point; take the shortest path from each first-level branch control point to the corresponding root node as the first-level branch control path; take the nodes on the first-level branch control path as the first-level branch nodes; By analogy, find the points with the smallest free water head in the branches connected to each r-th level branch node as the r+1-th level branch control point; take the shortest path from each r+1-th level branch control point to the corresponding r-th level branch node as the r+1-th level branch control path; take the nodes on the r+1-th level branch control path as the r+1-th level branch node; where r = 1, 2, ..., R-1, and the R-th level branch node is a leaf node in the branched water supply network model; Thus, the water supply network is determined from the 1st level branch control path to the Rth level branch control path.

6. The method according to claim 1, characterized in that The step S9 comprises: S9.1, initialize r=1; S9.

2. Calculate the optimal pipe diameter solution for the r-th level branch control path: S9.2.

1. Initialization t r =1; S9.2.

2. Determine the t r M alternatives for round optimization, where each alternative is a pipe diameter of an r-th level branch control path that is reduced by one specification based on the current pipe diameter according to the pipe diameter specifications in the standard pipe diameter set, and will not be reduced if the minimum pipe diameter in the standard pipe diameter set is reached; where M is the number of the r-th level branch control paths; S9.2.3, respectively solve the financial net present value of the reduced construction cost and the increased head loss Δh after the implementation of each alternative plan; S9.2.

4. Compare the increased head loss Δh after the implementation of each alternative solution with the corresponding surplus head H of the r-th level branch before the implementation of the corresponding alternative solution; determine whether there is an alternative solution with a corresponding Δh < H; if not, end the optimization of the r-th level branch control path, use the current pipe diameter plan of the r-th level branch control path as the optimal pipe diameter plan of the r-th level branch control path, and go to step S9.2.6; if so, select the plan with the largest net present value of the construction cost reduction among all alternative solutions with Δh < H as the optimal plan for the t r -th round, implement this plan, that is, update the pipe diameter according to this plan, and go to step S9.2.5; S9.2.5, let t r =t r +1, return to step S9.2.2; S9.2.

6. Let r=r+1 and return to step S9.

2.

7. An electronic device, characterized in that: include: Memory and processor; The memory is used to store computer programs; The processor is configured to call the computer program to execute the method according to any one of claims 1 to 6.

8. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program, and when the computer program is executed on an electronic device, the electronic device implements the method according to any one of claims 1 to 6.

9. A computer program product, comprising a computer program, characterized in that When the computer program is executed on an electronic device, the electronic device implements the method according to any one of claims 1 to 6.

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