Anti-cascade Reliability Model Of Urban Water Distribution Networks With MOPSO Algorithm

China is striving to build a resource-saving society,and its voice for sustainable urban development is also growing.The water supply system provides normal water for people 's daily lives.As urbanization continues to accelerate,residents and factories have increasingly high demands for water,and reliable pipe networks are needed to ensure it.Due to the differences in urban areas,the complexity of the water supply pipeline network varies,and the traditional pipeline network planning has many defects.Optimization problems in the water supply network generally involve meeting hydraulic performance,economic efficiency,water quality improvement,storage capacity control,and other important goals at the lowest cost.The water supply network is one of the city 's key infrastructure systems and plays a key role in safeguarding public health,promoting economic prosperity,and ensuring a good quality of life.However,the urban water supply pipeline network is highly sensitive and vulnerable to sudden disasters.Natural disasters or man-made damage to the water supply system will affect the various performances of the water supply system and lead to a reduction in the service level to users.Cascading reliability will also be affected.The purpose of this study is to mitigate the disastrous consequences of cascading failures on the urban water supply network,and to further weigh the economic and reliability goals of the network.Firstly,a flow-based cascading failure model of urban water supply network is established.This model combines engineering practice and complex network cascading failure theory,which can more realistically simulate the cascade evolution process of urban water supply network after failure.Secondly,in order to resist the cascading failure,improve the toughness of the water supply network,and further use the pipe diameter as the decision variable,and to minimize the construction cost of the water supply network and maximize the reliability of the cascading optimization goal,a multi-objective particle swarm optimization model was constructed.Finally,using MATLAB software,according to the principle of particle swarm optimization algorithm,optimization process and steps,write the main program of pipeline network optimization design,combined with the economic and reliability objective function and hydraulic constraints,wrote the water supply pipeline network cost objective function,adaptation Degree calculation,hydraulic reliability calculation and other subroutines,and then,iterate into a pipe network case for iterative analysis.Simulation results show that when the water demand factor is certain and the urban water supply network is seriously aging,even considering the high construction cost,the purpose of effectively resisting the cascading failure cannot be achieved.The regular maintenance of the urban water supply network is resistant to the urban water supply network.The promotion of cascading failures is of great significance.When the tolerance parameter is fixed,the water demand factor has a stable effect on the Pareto front of the urban water supply network against cascading failures.Among the formed Pareto fronts,supply exceeds demand and supply exceeds demand and demand balance is better than demand.In the case of short supply,the user's water consumption increases,and the urban water supply network's resistance to cascading failures decreases.To achieve the same resistance,the pipe diameter needs to be increased and the construction cost increased.Finally,the reliability and construction cost of the urban water supply network before and after optimization under the same water demand factor and tolerance parameters are compared.Under the same parameter setting conditions,after the optimization,the anti-cascade reliability of the water supply network is higher,the construction cost is lower,and the corresponding low-pressure head is also improved.The model comprehensively weighs the contradictory objectives and maximizes the reliability of the water supply network.It can provide a reference for relevant managers to the evolution process of the cascading failure of the urban water supply network.By summarizing the current research status of cascade failure prevention and control measures,effective control and prevention measures are proposed for the evolution of the cascade failure of the water supply network.