The Influence Of The Layout Of Diversion And Tail Water Branch Pipes On The Hydraulic Transition Process Of Pumped Storage Power Station

With the development of power grid scale,more and more pumped storage power stations are being built in China to take on the tasks of peak load regulation,valley filling,phase regulation and emergency standby,so as to improve the quality of power grid and optimize the power supply structure.Compared with conventional hydropower stations,pumped storage power stations have higher water head,longer pipeline,frequent unit condition conversion,and more complex hydraulic transition characteristics.The hydraulic transition process will cause the dramatic changes of the pressure and flow of the water conveyance system and the unit,which may cause serious harm to the water conveyance structure and the unit,and thus cause accidents.Therefore,it is of great significance to study the characteristics of the hydraulic transition process of the pumped storage power station in order to find out a reasonable control method and ensure the stable and reliable operation of the pumped storage power station.The hydraulic transition process of pumped storage power station is closely related to the layout of water channel.In this paper,through the method of simulation calculation,combined with the relevant characteristics of several typical pumped storage power station hydraulic transition process,the maximum speed rise rate of the unit,the maximum water pressure at the inlet of the spiral case and the minimum water pressure at the inlet of the draft tube are compared and analyzed under different arrangements of the water diversion system and the tail water system,so as to find out the change characteristics of the maximum speed rise rate of the unit,the maximum water pressure at the inlet of the spiral case and the minimum water pressure at the inlet of the draft tube Find out the control condition.At the same time,the influence of different positions of diversion bifulircated pipe and tailrace bifurcated pipe on the above three indexes is studied under the condition of the same load rejection and the successive load rejection of the unit,and the reasons are analyzed.The research results of this paper have certain reference value for similar projects,the main conclusions are as follows:1.For the asymmetric layout of water delivery system,it is unfavorable from the aspect of hydraulic transition process.The simultaneous or sequential load rejection of units is the control condition of the above three indexes.2.The change of bifurcated pipe position has great influence on the control index under the condition of successive load rejection.