Research On DMA Leakage Location By Pressure Regulating In Water Distribution System

The leakage in urban water supply pipe network mainly includes burst leakage,hidden leakage and background leakage.In order to solve the hidden leakage of domestic loop pipe network,together with the old way of detection that acoustic positioning methods were used frequently,this paper puts forward the corresponding leakage positioning method research.(1)Systematic study of this method,the main contents and implementation steps of this method are determined on the basis of hydraulic micro-model of pipe network and DMA partition:In this paper,the objective function mainly considers the variation value of head loss of the upstream and downstream pressure meters arranged in DMA under standard state and reduced pressure state,and the connections between the upstream and downstream pressure meters which decides the objective function are calculated by depth first algorithm.By further analyzing of the pressure measuring hot spots,it is determined that the real leakage points should be included in the corresponding regional points of the pressure measuring hot spots.As for the pressure hot spots,they can be determined by pressure values measured under standard and reduced pressure conditions combining with the connections between the upstream and downstream pressure meters.Then,the real leakage in the simulation can be estimated by fitting the pressure and flow data obtained from the pressure regulating experiment.Last but not the least,that leakage was distributed to each regional point corresponding to the pressure measuring hot spot for simulation,and the value of objective function obtained by comparing the measured and simulated data will be used for Chi-square test which lead to the leakage point accurately.(2)To verify the above method,the method is systematically verified by both verification experiment and numerical simulation:In verification experiment,the method is applied to the DMA in area M to verify the above method content and implementation process in single loss situation.Then,the result shows that the calculated loss point J29(58# E)is the closest node near the hydrant with the leakage of 1 L/s,demonstrating the feasibility of the method.While,the simulation of example is used to verify both the single and multiple leakage of the circular pipe network.What is more,the consequence shows that the leakage points J32 and J27 which are adjacent have Bi values of 0.720 and 0.758,considering that J27 is the actual leakage node,the applicability of the method to the single leakage location of circular pipe network is demonstrated.Further more,the positioning result of the multi-leakage simulation is point combination J24 and J23.In addition,J23 has a low Bi value of 0.593 which is adjacent to J27,together with the actual leakage nodes J24 and J27,the applicability of the method to the multi-leakage location of the loop network is demonstrated.Besides,The error analysis of the simulation as well as the fitting under the circumstance of differernt pressure measuring hot spot schemes are discussed.Then,the important factors that mainly affect the accuracy of the method(pressure regulating range,the amount of the leakage and the distribution of leakage points)get the sensitivity analysis.Through the above verification and analysis,the method is improved and the applicability of the method is tested,combing with the good results caculated.(3)Software application research: through the application research of software requirements,system composition,system flow,architecture and each module,the method is softwarefied and systematized.