Study On Joint Optimal Scheduling Of Multi-waterworks In Urban Water Supply System

The scheduling of urban water supply network system has been an important issue of concern to the water industry for many years.The joint water supply system of multi-water plants has complex linkage relationship,multi-dimensional decision variables and many constraints,which puts forward higher requirements for conventional scheduling and emergency scheduling.In this paper,the hydraulic model of large-scale complex water supply system with multiple water sources and multiple water plants is established,and the flow and pressure distribution of the water supply system are obtained by simulation calculation.Then,on the basis of the hydraulic model simulation results,considering the storage effect of the clear water tank and its collaborative optimization with pump scheduling,the power consumption is transferred to the low price period to improve the energy efficiency of water supply and reduce the cost of water supply.Finally,according to the possible accident scenarios of water supply system,the multi-objective fuzzy optimization of emergency plan is carried out according to the decision preference index,and the optimal decision scheme is obtained.The main contents and results are as follows :(1)Data collection and status assessment.The water supply system of L city is selected as the research object.The basic situation of water supply source and the operation data of water supply system in L city are comprehensively investigated and collected.The data are divided into static data and dynamic data,and processed and analyzed.Through experiments,the pump characteristic curve is fitted,the collocation method and operation time of pumps under the current scheduling are analyzed,and the operation efficiency is evaluated.The historical operation data of the cleaning pool before the pump are analyzed,and the adjustment status of the cleaning pool is evaluated.The results show that the water pumps in the raw water system of L city are not all in the efficient operation range,and do not give full play to the storage function of the clear water tank,which has large optimization space.(2)Large-scale city water supply network hydraulic modeling.The micro-hydraulic model of water supply dispatching in multi-source and multi-water plants is constructed by EPANET,including graphic element simulation,state simulation and parameter simulation.Combined with the simulation requirements and hydraulic equivalent principle,the topological structure is reasonably simplified.The simulation results are compared with the actual monitoring results of the monitoring points,and the model is checked until the verification standard is met to simulate water allocation.(3)Joint optimal scheduling of multi-source and multi-water plants.Making full use of the flexibility of the joint regulation of the variable frequency pump and the water tank before the pump,a two-stage optimal scheduling model is established and solved by genetic algorithm.The opening and closing of the pump and the frequency conversion in each period of the scheduling cycle are determined,and the flow rate into each clear water tank in each period is determined.The optimization results show that the joint optimization scheduling of multi-water plants can coordinate the operation state of the pump and the clean water pool at the same time,and achieve the lowest operation cost of the pump in the whole water supply system.The cost of the optimized water supply system is reduced by 12.03 % compared with that before optimization.(4)Multi-objective emergency scheduling plan optimization.Combined with the actual operation of the water supply system,the possible emergency scenarios are introduced.Based on the expert experience,the emergency water supply dispatching plan library and decision preference index are established.After the hydraulic model is used to evaluate and test the plan set,the multi-objective fuzzy optimization is carried out to formulate a scientific dispatching plan.The results show that the multi-objective fuzzy optimization principle can be well applied to the decision-making selection of emergency scheduling.This emergency plan library can better assist emergency scheduling.