Research On Optimal Operation And Resilience Assessment In Water Distribution Network

The current high energy consumption in urban water supply systems needs to be solved urgently.However,most of the existing studies on optimal operation of water supply system focus on modeling issues with the deterministic energy conservation optimization,ignoring the existence of uncertainty in system operation and lagging behind the actual application requirements.At the same time,as the lifeline of urban development,the water supply system needs to have the ability to absorb the disturbance of uncertainty.However,in the current research on water supply system performance evaluation,there is a lack of research on the impact of operational control on system performance.Based on that,this thesis first takes the secondary pressurized water supply system with variable-speed pump station as the research object,adopts three kinds of pump station regulation methods to compare the operation energy consumption and performance.Then,an optimal scheduling model with the water demand uncertainty is proposed,and an optimal scheduling solution with different threshold levels is optimized.On this basis,API indicators and MRI indicators were selected to examine the disturbance performance of the scheduling solution.At the same time,an uncertain accident was simulated and the influence of the analysis system on the disturbance of the system was evaluated.The main research results obtained are as follows:For the high energy consumption of the secondary pressurized water supply system with variable-speed pumping stations,the genetic algorithm is applied to optimize the most energy-saving pumping station outlet variable pressure control scheme.In the optimization process,based on the energy-saving optimization of the parallel-connected pump group,the optimization process is effectively simplified;considering the change of the pump efficiency curve of the variable-speed regulation,the calculation of the operation energy consumption is more accurate;Compared with the constant pressure control scheme of the pump station outlet,The variable pressure control method can combine the changes in the water demand of the system,change the output of the pumping station through frequency control,reduce the unnecessary waste of energy,and save energy;with maintaining the constant pressure of the most unfavorable water distribution point,it can strengthen the system's ability to resist adverse conditions.In the problem of optimal scheduling of urban water supply systems with water supply and pumping stations,the water demand uncertainty of the water nodes is considered,and the probabilistic constraints of the pressure heads of the nodes are established,the threshold level is introduced,and two kinds of probabilistic constraint treatment methods are improved,with correction coefficients.The numerical integration method and the stochastic sampling method of mathematical statistics,based on the analysis of the uncertainty analysis,verify the effectiveness of the two constraint processing methods.At the same time,the optimization results show that the pump station serves as the energy source of the system and its specific water pump.The arrangement plan determines the system's ability to withstand the uncertainty of demand.That is,the higher the threshold level requirement is,the more work pumps required for system control to maintain normal operation,and the stronger the anti-interference ability to the uncertainty of water demand.Firstly,the API and MRI are selected to evaluate the resilience performance of the above-mentioned optimal solutions.The results show that MRI can effectively represent the changes in the node's excessive energy compared to API and it is more suitable for resilience evaluation of system regulation and operation.At the same time,the pipe break accident was chosen as an uncertain condition and based on the calculation of pressure driven demand,the failure rate of water demand in the system was accurately evaluated.The result proves that the regulation operation plan considering the uncertainty of water demand,in the face of uncertain conditions,has sufficient available energy to provide pressure for the node during the failure period.Considering that the higher the threshold level,the more significant the system's energy replenishment function,the smaller the loss of the system failure conditions,and the stronger the system's ability to withstand adverse conditions.