Research On Close-valve Strategy Of Multiple Accident Points And Safety Guarantee Of Urban Water Supply Network

As the progress of urbanization, a large number of villagers pour into city. Theburden of water supply network becomes greater continuously because of theincreasingly urban water consumption, together with part of pipes are aging seriouslyas they were laid relatively agelong, the burst-event is occurred occasionally.Differences to network’s leakage, once the burst-event happens, it will be greatlyharmful to the network. In order to minimize the economic loss, the valves must beclosed rapidly to rush repair the network and corresponding measures should beadopted. Core of this paper is the close-valve strategy of multiple accident points, thevariation of multi-sources network’s water supply partitions before and after theaccident and safeguard measures of water supply are studied to make it applied inactual network better.The study of the zoning of multi-sources network is based on graph theory.Nodes of the network are the “points” in graph theory and pipes are “arcs”, so therelationship between one node and another can be expressed by adjacency matrix. Themodel of network is built by EPANET network simulation software. Starting from onesource node, along the flow direction, node which the source can supply water to issearched for one by one and cut-off points can be found, then water supply partitionscan be formed by them.The breadth-first search algorithm is utilized to research the close-valve strategy.The strategy of single accident point is studied at first, then research of the strategy ofmultiple accident points can be based on it. The strategy of multiple accident pointsmay be not equivalent to the superposition of every single strategy as water supplynetwork is intricate. At last, in order to realize generality of the algorithm of closevalve strategy, make it into a DLL file that can be called by other main program sothat the study afterward will become conveniently.After the close-valve strategy of multiple accident points is formed, takingseveral different types of accidents for examples, water supply partitions afteraccident can be formed by using its algorithm. Comparing with water supplypartitions under normal state, research the variation and analyze the causes combinewith network’s flow diagram and try to find the main factors of water supply partitions affected by accident. Then optimal operation under accidental state isbriefly investigated on aspects of both economic and safety.The security of water supply network is impacted greatly as the accident happens.The technology of safety guarantee of water supply should be researched on bothhydraulic and water quality. The free hydraulic pressure and residual chlorine aretaken as objects, the variation of them after accidents happened are studied andcorresponding measures are put forward to make the network can supply water to thenodes and pipes those out of the affected area safely, stably and continuously whenthe network is being rush repaired.