Research On Leakage Assessment And Leakage Control Of Water Distribution System

The water distribution system will lose a lot of water due to pipeline leakage.According to statistics,globally,non-revenue water accounts for about 27% of the total water distribution.Pipeline leakage is the main component of non-revenue water.The water distribution network is an important carrier in the process of water transportation.Therefore,the cause of leakage should be studied in depth to control and reduce the water loss.In actual production,the water company is often unable to accurately assess the regional leakage level due to the lack of data.Due to the periodicity of the collected data,the managers cannot grasp the changes of the leakage level in real time.At the same time,how to choose and implement the leakage control strategy is also a big problem for the water company.Therefore,this study mainly focuses on the following three aspects: leakage assessment and analysis,leakage monitoring and diagnosis,and leakage control analysis.The main research results obtained in this study are as follows:Combining the "top-down leakage assessment" method based on water balance table and the "bottom-up leakage assessment" method based on the minimum night flow,a comprehensive leakage assessment method with high applicability is proposed,which takes real leakage as the focus of assessment and the apparent leakage as the final point of assessment.In order to calculate the actual leakage under the limited data and successfully complete the leakage assessment work,a method for evaluating the legal water consumption at night is proposed: according to the user data matching the intraday variation law of water consumption data provided by the regional master meter,the intraday variation law of user data is obtained,so as to calculate the legal water consumption corresponding to the minimum night flow.Kalman filtering can better eliminate the influence of system noise and interference,perform accurate trend analysis,using Kalman filtering to assist minimum night flow to monitor the change of system loss has a good effect.According to the comparative analysis results of KL values of different communities,it can be seen that the leakage level of the communities with cast iron pipes,small pipe age,direct supply and pressurization is generally low,and the number of users has little relationship with the leakage rate.When the pipeline network topology is simple and the variation of daily water demand is small,it is recommended to install a pressure reducing valve to implement system pressure control,which can achieve good loss control and leakage reduction effects,obtain economic benefits,and simplify installation work to save equipment installation costs.When the pipeline network topology is complicated and the variation of daily water demand is large,the real-time pressure control strategy is recommended to adjust the water supply pressure of the system reasonably,reduce the leakage caused by high water pressure to the maximum extent,and obtain the maximum economic benefits.Compared with the traditional general reliability optimization model,the fuzzy reliability optimization model fully considers the adjustability of the pressure head in actual operation.Based on the allowable range,it seeks the optimization decision of the preference leakage target.Helps to formulate scheme plans with better leakage control benefits.In the optimal scheme of fuzzy reliability,pipeline replacement and valve installation are more concentrated in high-pressure areas and water sources.At the same time,in order to ensure the leakage control effect of the system,the system reliability is improved with a larger valve opening group and a larger pipe diameter.