Water pump-pressure control valve combined dispatching method and device for urban water supply network

Abstract

The invention discloses a water pump-pressure control valve combined dispatching method for an urban water supply network. The method comprises the following steps: constructing a hydraulic model; based on the hydraulic model, the opening degree of a pressure control valve in the water supply system and the operation rotating speed and the operation lift of a water pump serve as decision variables, water saving cost, water pump energy consumption saving cost and pipe network leakage control effect maximization serve as targets, and a water pump-pressure control target function is built; and setting a constraint based on a water demand in the water supply system, solving the water pump-pressure control objective function, and evaluating a solving result to output an optimal scheduling scheme. The invention further provides a water pump-pressure control valve combined dispatching device. The method provided by the invention can provide a scientific, reasonable and effective evaluation basis for the optimal scheduling of the water pump-pressure control valve of the municipal water supply network.

Description

Technical Field

[0001] The present invention belongs to the technical field of urban municipal water supply systems, and in particular relates to a water pump-pressure control valve combined dispatching method and device for an urban water supply network. Background Art

[0002] As one of the important auxiliary means to decide the operating status of the water supply network, optimal scheduling refers to the use of optimization technology to select a reasonable, reliable and economical operation scheduling plan from all possible scheduling plans based on the operating status of the network or predicted data, on the premise of ensuring that the water demand of users is met, so as to obtain good economic and social benefits.

[0003] Joint dispatching of water pumps and pressure control valves in water supply networks is an effective way to control leakage and reduce energy consumption. However, traditional dispatching methods are mostly based on manual experience. In actual operation, the problems that need to be solved involve many aspects and dimensions. Considering only one level or dispatching only based on experience cannot achieve the overall optimality and has many defects. In actual pipe networks, the optimization dispatching capabilities of pressure control valves are not fully utilized, and there is a lack of an evaluation system for the application of pressure control valves after deployment, resulting in a lack of effective feedback on the optimization dispatching effect. Traditional dispatching methods mostly rely on manual experience, the overall dispatching level is low, and unreasonable pump and valve optimization dispatching schemes may lead to management chaos. On the other hand, due to the lack of a universal evaluation method for pump and valve dispatching of water supply systems, most water companies only use system energy consumption as the only indicator for operation dispatching selection, and cannot fully measure the true effect of system dispatching.

[0004] Patent document CN118211814A discloses a method and system for optimizing and scheduling a water supply network based on data analysis. The method divides a water supply network into multiple target areas, and deploys multiple groups of detection points on the network within the target area to collect water supply, water pressure, flow data and water quality data; obtains historical water consumption and population data in the target area and inputs them into a pre-trained predictive water consumption model, and outputs the predicted water consumption of the target area; adjusts the water supply of the target area according to the predicted water consumption and a water supply scheduling strategy; calculates the water supply quality index of the target area after the water supply is adjusted according to the water pressure data, flow data and water quality data, obtains the water supply abnormality by combining the water supply quality index with the actual water consumption, compares the water supply abnormality with the water supply abnormality threshold interval, and judges the current state of the target area as abnormal water supply, normal water supply or network failure according to the comparison result.

[0005] Patent document CN118052326A discloses a method for predicting water consumption of a campus water supply network based on a neural network. The method uses a neural network to predict water consumption. First, sensors or monitoring points are used to collect pipeline characteristics and flow data under normal water supply conditions of the network. Secondly, the data is cleaned and screened, and a time series method is established. Then, based on the collected data, a network node flow prediction model based on a BP neural network is constructed and trained. Finally, the predicted value is obtained to achieve reasonable evaluation and scheduling of water consumption. The difference between the predicted value and the actual value is compared to further predict the leakage of the network. Summary of the invention

[0006] The purpose of the present invention is to provide a water pump-pressure control valve joint scheduling method and device for urban water supply pipeline network, which can provide a scientific, reasonable and effective evaluation basis for the optimal scheduling of water pump-pressure control valves in municipal water supply pipeline network.

[0007] In order to achieve the first object of the present invention, the following technical solution is provided: a water pump-pressure control valve joint scheduling method for an urban water supply network, comprising the following steps:

[0008] Based on the structural parameters and layout of the pipes, pumps and valves in the water supply system, and obtaining the pipe network data of the water supply system under various working conditions, the corresponding hydraulic model is constructed;

[0009] Based on the hydraulic model, the opening of the pressure control valve in the water supply system, the operating speed and the operating head of the water pump are taken as decision variables, and the water saving cost, the water pump energy saving cost and the maximization of the pipe network leakage control effect are taken as the goals to construct the water pump-pressure control objective function;

[0010] Constraints are set based on the water demand in the water supply system, the water pump-pressure control objective function is solved and the solution results are evaluated to output an optimal scheduling plan, which includes the opening of the pressure control valve, the operating speed and the operating head of the water pump.

[0011] The present invention takes the difference between the total cost of water leakage fee, energy consumption and electricity fee and the cost of new components as the goal, constructs an optimization layout model, determines the objective function, decision variables and constraints, takes into account the component information of the pipeline network, focuses on ensuring the requirements of special nodes and special working conditions, and achieves a relative global optimum.

[0012] Specifically, the pipeline network data includes operating flow and pressure parameters of each node in the pipeline.

[0013] Specifically, the constraints include hydraulic balance constraints, node pressure constraints and variable frequency pump speed constraints.

[0014] Specifically, the hydraulic balance constraints include a continuity equation, a pipe section pressure drop equation group, and a ring energy equation.

[0015] Specifically, the expression of the variable frequency pump speed constraint is as follows:

[0016]

[0017] In the formula, is the lower limit of the speed ratio of the variable frequency pump; n p,k(var)min is the operating speed of the variable frequency pump; n p,d is the rated speed of the variable frequency pump motor.

[0018] Specifically, the expression of the water pump-pressure control objective function is as follows:

[0019] In the formula, E pump is the operating power of the water pump; Q pump A is the running flow of the water pump; E is the electricity price; A w is the water price; L E is the economic loss coefficient of leakage, N S is the total number of nodes, C L is the leakage constant, p i,t is the pressure of node i in time period t, L t,i is half of the sum of the lengths of the pipes connected to node i, γ is the leakage exponential coefficient, and p i ' ,t is the pressure at node i after the pressure control valve is installed.

[0020] Specifically, the evaluation result is obtained by weighting the pressure control effect index, the leakage control effect index and the energy saving and cost reduction effect index.

[0021] In order to achieve the second objective of the present invention, the following technical solution is provided: a water pump-pressure control valve joint scheduling device, which is implemented by the water pump-pressure control valve joint scheduling method provided above, and the specific steps are as follows:

[0022] Based on the basic data of the water supply system to be scheduled and the weights in the preset evaluation process, the optimal scheduling plan is output.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] A comprehensive evaluation method for the joint dispatching effect of water pumps and pressure control valves is proposed, which takes into account the subjective experience and knowledge of experts in the evaluation process and the objective information in the data, filling the gap in the evaluation of the dispatching effect of water pumps and pressure control valves in urban water supply systems; through the comprehensive evaluation of the optimal dispatching of pressure control valves, a combination of quantitative and qualitative methods is adopted to conduct a comprehensive, systematic and dynamic evaluation of the optimal dispatching effect of the pressure reducing valve, so as to achieve pressure balance and energy saving in the water supply network, and reduce leakage rate and operating costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 A flow chart of a water pump-pressure control valve joint dispatching method for an urban water supply network provided in this embodiment;

[0026] Figure 2 A flow chart for constructing a water pump-pressure control objective function provided in this embodiment;

[0027] Figure 3 A graph showing a change in leakage reduction at a certain pipe network node 7 under different control pressures provided in this embodiment. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical scheme and advantages of the embodiments of the present invention clearer, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings here can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0029] like Figure 1 As shown, a water pump-pressure control valve joint scheduling method for a city water supply network provided in this embodiment includes the following steps:

[0030] Based on the structural parameters and layout of the pipes, pumps and valves in the water supply system, and obtaining the pipe network data of the water supply system under various working conditions, the corresponding hydraulic model is constructed;

[0031] Based on the hydraulic model, the opening of the pressure control valve in the water supply system, the operating speed and the operating head of the water pump are taken as decision variables, and the water saving cost, the water pump energy saving cost and the maximization of the pipe network leakage control effect are taken as the goals to construct the water pump-pressure control objective function;

[0032] Constraints are set based on water demand in the water supply system, and a genetic algorithm is used to solve the water pump-pressure control objective function and evaluate the solution results to output an optimal scheduling plan, which includes the opening of the pressure control valve, the operating speed and the operating head of the water pump.

[0033] Furthermore, if Figure 2 The flowchart of the construction of the pump-pressure control objective function provided by this embodiment is shown. First, a high-precision hydraulic model of the water supply system is established: the construction of the hydraulic model of the water supply network is the process of establishing a mathematical model for the simulation network system. The prototype of the simulated network can be virtual or real. The simulation content mainly includes graphics, states, parameters, etc., where the graphics refer to the network graphics that can realize calculation simulation after the complex network topology is simplified and optimized, including water sources, nodes, pipe sections and other components. The state refers to the node water demand, pressure, pipeline flow, flow velocity, etc. that change with time, and the parameter simulation is the pipeline resistance coefficient C value, the pressure control valve flow coefficient Kv, and the water pump HQ characteristics.

[0034] Set the decision variables: pressure control valve opening, water pump operation combination, water pump operation speed, and hydraulic parameters of each pipe section of the pipe network output by the above water supply system hydraulic model.

[0035] Constraints: 1) The pipe network satisfies the hydraulic balance constraints, including the continuity equation, the pipe section pressure drop equation group, and the ring energy equation.

[0036] 2) Node pressure constraint, taking into account that the water supply network needs to meet the minimum head demand of each user node.

[0037] 3) In order to prevent the variable frequency pump from running in an excessively poor operating range, the speed of the variable frequency pump needs to be constrained:

[0038]

[0039] In the formula, is the lower limit of the speed ratio of the variable frequency pump; n p,k(var)min is the operating speed of the variable frequency pump; n p,d is the rated speed of the variable frequency pump motor.

[0040] Based on the parameters set above, the objective function is constructed:

[0041] Among them, E pump is the operating power of the water pump; Q pump A is the running flow of the water pump; E is the electricity price; A w is the water price; L E is the economic loss coefficient of leakage, N Sis the total number of nodes, C L is the leakage constant, p i,t is the pressure of node i in time period t, L t,i is half of the sum of the lengths of the pipes connected to node i, γ is the leakage exponential coefficient, and p i ' ,t is the pressure at node i after the pressure control valve is installed.

[0042] like Figure 3 As shown in the figure, it is a graph showing the change in leakage reduction of a certain pipe network node 7 under different control pressures provided in this embodiment. It can be seen from the figure that the leakage of the pipe section can be significantly reduced by scheduling the pressure control valve. The node pressure should be reduced as much as possible while ensuring that the node water demand is normally met.

[0043] The evaluation process proposed in this embodiment is as follows:

[0044] Pressure control effect index: The evaluation method focuses on the pressure control accuracy of the pressure control valve. The index for measuring the pressure control effect of the pipeline network is shown in the formula.

[0045]

[0046] w P The total number of water terminals in the valve control area is S1, and i represents the i-th water terminal in the valve control area. The service head at i after adjustment at time t is The service head at point i before adjustment is The standard service water head of water terminal i is θ i Characterizes the weight coefficient of the flow of water user terminal i in the total flow of the region.

[0047] Among them, w P It reflects the accuracy of the pressure control valve in regulating the water head of the pipe network. Its value is 0-1. The larger the value, the closer the water head within the pressure control valve's control range is to the standard service water head, and the better the pressure control effect of the pressure control valve.

[0048] Leakage control effect indicators: The evaluation of pipeline network leakage control effect is mainly based on the leakage reduction rate.

[0049] According to the leakage reduction rate, the pipeline network leakage control effect indicator formula was constructed.

[0050]

[0051] Leakage control effect L , which is mainly characterized by the reduction rate of leakage before and after the pressure control valve is installed. represents the water supply of the water supply network at time t, represents the water consumption of the water supply network at time t, It means that the water consumption before the pressure reducing valve optimization scheduling is Historical water supply at that time.

[0052] Among them, w L It indicates the control effect of the pressure control valve on the leakage of the pipeline network. The value range is 0-1. The larger the value, the better the control effect and the more the leakage is reduced.

[0053] Energy saving and cost reduction effect index: The purpose of water pump-pressure control valve scheduling is to reduce the leakage of the pipeline network, save water resources and pump energy consumption. To this end, an energy saving and cost reduction effect index is set. Cost savings C within T time R It can be simply expressed as: Through this scheduling, the water cost C saved in time T W and pump consumption cost C E sum.

[0054]

[0055] The meaning of each parameter in the formula is: A W is the local water price per ton, E W A is the electricity consumption per ton of water for the local municipal water supply unit. E is the local electricity price, DN is the nominal diameter of the pressure control valve, and a, b, and c are constants related to the valve price.

[0056] Among them, w c It indicates the cost saving rate after installing the pressure control valve. Its value range is 0-1, reflecting the energy-saving and cost-reduction effect of installing the pressure control valve. The larger the value, the better the energy-saving and cost-reduction effect of installing the pressure control valve.

[0057] In order to comprehensively evaluate the above three indicators, namely, the pipeline pressure control effect index, the pipeline leakage control effect index and the energy saving and fee reduction effect index, weight coefficients α, β, and γ are introduced, and the three coefficients are used to represent the importance of the three indicators.

[0058]

[0059] In the formula, α, β, and γ respectively represent the importance of the three indicators in the comprehensive evaluation, namely, the pipe network pressure control effect index, the pipe network leakage control effect index, and the energy saving and cost reduction effect index. f comprehensively reflects the effect before and after the installation of the pressure control valve. The larger its value, the better the control effect of the pressure control valve.

[0060] This embodiment also provides an expert review method based on actual conditions, and uses the average value as the final result, as shown in Table 1.

[0061] At this time, the comprehensive evaluation index formula becomes:

[0062]

[0063] Table 1

[0064]

[0065] The comprehensive evaluation of the optimal scheduling of pressure control valves adopts a combination of quantitative and qualitative methods to conduct a comprehensive, systematic and dynamic evaluation of the optimal scheduling effect of the pressure reducing valve, achieve pressure balance and energy saving in the water supply network, and reduce leakage rate and operating costs.

[0066] This embodiment also provides a water pump-pressure control valve joint scheduling device, which is implemented by the water pump-pressure control valve joint scheduling method provided by the above embodiment.

[0067] In order to better illustrate the effect of the method provided by this embodiment, the following specific examples are provided for illustration:

[0068] A water supply area in the central urban area of ​​a certain city in China was selected for simulation calculation. The area consists of 1 water supply pump station and 13 pressure control valves. Based on the operating conditions of the average water consumption period of a certain day in the area, we developed four different scheduling schemes and calculated their pump-pressure control valve joint scheduling evaluation values ​​respectively. Among these schemes, Scheme 1 focuses on optimizing the pressure control effect, Scheme 2 focuses on the leakage control effect, and Scheme 3 focuses on the energy saving and cost reduction effect. Scheme 4 of the present invention comprehensively considers the pressure control effect, leakage control effect and energy saving and cost reduction effect. Through simulation calculation, we found that the scheduling evaluation value of Scheme 4 is significantly better than that of the other three schemes, showing its significant improvement in overall effect. In particular, Scheme 3, that is, the scheduling strategy that only considers the energy saving and cost reduction effect, shows a lower scheduling evaluation value, emphasizing the shortcomings that may be caused by single indicator scheduling. These results not only verify the effectiveness of the method of the present invention in practical applications, but also provide strong theoretical and empirical support for further optimizing the scheduling of urban water supply pipe networks.

Claims

1. A water pump-pressure control valve joint dispatching method for an urban water supply network, characterized in that: The following steps are involved: Based on the structural parameters and layout of the pipes, pumps and valves in the water supply system, and obtaining the pipe network data of the water supply system under various working conditions, the corresponding hydraulic model is constructed; Based on the hydraulic model, the opening of the pressure control valve in the water supply system, the operating speed and the operating head of the water pump are taken as decision variables, and the water saving cost, the water pump energy saving cost and the maximization of the pipe network leakage control effect are taken as the goals to construct the water pump-pressure control objective function; Constraints are set based on the water demand in the water supply system, the water pump-pressure control objective function is solved and the solution results are evaluated to output an optimal scheduling plan, which includes the opening of the pressure control valve, the operating speed and the operating head of the water pump.

2. The water pump-pressure control valve joint scheduling method according to claim 1 is characterized in that: The pipeline network data includes the operating flow and pressure parameters of each node in the pipeline.

3. The urban water supply network water pump-pressure control valve joint dispatching method according to claim 1 is characterized in that: The constraints include hydraulic balance constraints, node pressure constraints and variable frequency pump speed constraints.

4. The water pump-pressure control valve joint scheduling method according to claim 3 is characterized in that: The hydraulic balance constraints include continuity equations, pipe section pressure drop equations, and ring energy equations.

5. The water pump-pressure control valve joint scheduling method according to claim 3, characterized in that: The expression of the variable frequency pump speed constraint is as follows: In the formula, is the lower limit of the speed ratio of the variable frequency pump; n p,k(var)min is the operating speed of the variable frequency pump; n p,d is the rated speed of the variable frequency pump motor.

6. The water pump-pressure control valve joint scheduling method according to claim 1, characterized in that: The expression of the pump-pressure control objective function is as follows: In the formula, E pump is the operating power of the water pump; Q pump A is the running flow of the water pump; E is the electricity price; A w is the water price; L E is the economic loss coefficient of leakage, N S is the total number of nodes, C L is the leakage constant, p i,t is the pressure of node i in time period t, L t,i is half of the sum of the lengths of the pipes connected to node i, γ is the leakage exponential coefficient, and p i ' ,t is the pressure at node i after the pressure control valve is installed.

7. The water pump-pressure control valve joint scheduling method according to claim 1, characterized in that: The evaluation result is obtained by weighting the pressure control effect index, the leakage control effect index and the energy saving and cost reduction effect index.

8. A water pump-pressure control valve joint dispatching device, characterized in that: This is achieved by the water pump-pressure control valve joint scheduling method as described in any one of claims 1 to 7.

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