Application Study On Water Distribution Network Hydraulic Modeling And Optimal Operation

With the increase of the scale and complexity of the water supply system,the limitations of the traditional operation and management scheduling mode according to the experience have gradually become prominent.The exposure of many problems such as energy consumption and leakage rate has proposed new requirements for the city water departments of scientific and effective management.So this paper studies on the establishment of water distribution network hydraulic model and the development and application of optimal operation model,expecting to obtain great social and economic benefits which has important practical significance.Basic information data of the pipe network is collected based on the geographic information system(GIS)and supervisory control and data acquisition system(SCADA)established in Huzhou city.The topology structure of network is established through operations such as simplification and troubleshooting.Minimizing the difference between the monitoring value and the simulation value of water source water,node pressure and pipe flow is proposed as the objective function based on the hydraulic calculation equations.Also,the sensitivity matrix of the node water demand to the monitoring data is constructed.The singular value decomposition algorithm is used to solve the problem.The sensitivity of the flow monitoring data to the change of water demand and the actual situation in Huzhou city is taken into account during the hydraulic model calibration process,so the flow monitoring is given a greater weight.Twenty-four water supply periods on October 25,2017 are taken as the examples.The calibration results show that the calibration effects are good enough to meet the criteria well.Considering that the indirect optimal scheduling model may not be able to obtain the optimization schedule,this paper studies on establishing direct optimal operation model based on the genetic algorithm.The electricity consumption of pump stations of three waterworks in the urban area of Huzhou city is considered as the objective function.The constraints are transformed in the form of penalty functions.The opening states of thirteen fixed-speed pumps and the setting speed of two variable-speed pumps are used as decision variables.The speed is set from 0.75 to 1.The application of direct optimal operation model is also carried out by taking 24 water supply periods on the day.It is concluded that the optimized schedule avoids the situation of insufficient pressure at the most unfavorable monitoring points in the original schedule that improves the reliability of water supply system.Also,it can save electricity consumption of 9763 kWh throughout the day.Energy saving effect is obvious that the saving efficiency is 8.8%.In addition,considering the actual application of optimal operation model that may influenced by water production capacity of waterworks and water supply constraints,it may be necessary to provide a pump optimal schedule in the case where the water supply amount of each water plant is fixed.In this paper,the water supply of each plant is consistent with the actual plan by adding constraints.Taking the highest water supply moment of the day as an example,the electricity consumption was reduced by 357 kWh that the energy saving percentage was 6.07%.Finally,the sum of power consumption of water plant pump stations and water loss of the network is taken as the objective function from the perspective of reducing the leakage of the system.Current water supply demand is divided into effective water supply demand and water leakage demand.The actual water demand is used to initialize the water demand of the pipe network,then the cyclic operation is carried out,including optimal operation model application,assessment of leakage amount and water demand update.At last,the optimal schedule considering leakage is obtained.The 24 water supply periods on the day are still applied as the examples.Comparing the schedules before and after the optimization,it is found that the large water supply period can reduce the proportion of demand by about 10%,and about 20%of electricity consumption.The importance of scientific optimization scheduling is unquestionable.The total water supply was reduced by 20,300 m3.If the water price is 5 yuan/m3,it can save money over 100,000 yuan.At the same time,the total power consumption of pump stations can be saved to 18966 kWh,and the energy-saving efficiency is as high as 17.2%.The total cost of water and electricity can be saved more than 110,000 yuan that the energy-saving effect is remarkable.The water supply pressure of each water plant in each period is reduced and balanced,which is beneficial to reduce the pressure of the pipe network and leakage rate,also the burst rate.