| Miyun Reservoir regulation and storage project is a key project to ensure the safety of water supply in Beijing,which greatly alleviates the tight balance of water supply and demand in Beijing.The project is affected by the influent conditions and the characteristics of the unit,the operation of the pump deviates from the design condition for a long time,and the unit has low efficiency and high energy consumption.Under the background of "carbon peak" and "carbon neutral",there is an urgent need for energy saving and economic operation of pumping stations.Optimal scheduling is one of the most effective ways to save energy and reduce consumption in cascade pump station,and it is one of the important tasks in the operation of water transmission system.At the current operation stage,four units in the first six pump stations of Miyun Reservoir regulation and storage project are equipped with two frequency converters,and the combination of power frequency/frequency conversion units increases the adaptability of flow.The previous economic operation model and economic operation plan of a single station are no longer applicable.Therefore,it is urgent to carry out research on optimal operation of cascade pump station under the combined condition of power frequency/frequency conversion,so as to provide a sound theoretical basis for formulating rational,reliable,safe and economical cascade pump station dispatching operation scheme.Based on the one-dimensional hydrodynamic model of open channel,combined with the theories of economic operation model and intelligent optimization algorithm of pump station,this paper developed the optimal operation model of cascade pump station,carried out three studies on hydraulic loss calculation and analysis of pipeline and channel,economic operation of water transmission of single stage pump station considering frequency conversion unit,and multi-condition optimization scheduling of cascade pump station group.The main research results and conclusions are as follows:(1)The one-dimensional hydrodynamic model of open channel was established,and the accuracy of the model was verified by the measured data and the error sources were analyzed.The results show that the relative error of the numerical model is less than 0.06%,and the results of the numerical model are reliable.The results show that with the increase of the water flow,the hydraulic loss of open channels in the actual lifting head increases.It is clear that the hydraulic loss of open channels cannot be ignored when studying the optimal distribution of the head of the step pump station with long distance open channels.(2)Based on the flow control principle of frequency conversion unit,the relationship between blade Angle--speed--flow--head is deduced,and the flow distribution model of the unit considering frequency conversion is constructed.The model is applied to the first six pump stations of Miyun reservoir regulation and storage project.The research shows that the frequency conversion unit can increase the flow operation interval,and the frequency conversion unit can obviously improve the operation efficiency of the pump station under some specific working conditions.Taking the actual operating conditions of pump stations at all levels as an example,comparing the original operation mode with the operation mode with the addition of frequency converter,the results show that the efficiency of pump stations at all levels is increased by about 1.1%,and the total daily energy consumption of the whole cascade pump station is saved by about 2.15%.(3)Based on the one-dimensional hydrodynamic model of open channel and the unit flow distribution model considering frequency conversion,the head optimization distribution model of cascade pump station is constructed,and the head optimization distribution table of cascade pump station in Tuanchenghu-Huairou reservoir section under actual operating conditions is calculated.The results show that the energy consumption of the optimized cascade pump station is reduced by 11.06%.At the same time,the head optimization distribution table of the cascade pump station under all working conditions is calculated to provide an effective operation scheme for the economic operation of the cascade pump station and ensure the economic operation of the cascade pump station. |
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