The Research On Calculation Method And Control Strategy Of Natural Ventilation For Underground Powerhouse Of Pumped Storage Power Station

Pumped storage power station plays an important role in ensuring the safety of the power system,flexible load-frequency regulation,and promoting the consumption of renewable energy.The development demand continues to grow.Pumped storage power stations will produce a large amount of heat dissipation during operation.If the underground powerhouse uses vertical shaft to exhaust air,it is easy to generate large natural ventilation power,which has huge energy-saving potential.Pumped storage power stations have the characteristics of periodic transitions of various working conditions,and the supply air tunnel is prone to air condensation in hot and humid seasons.These factors make the natural ventilation changes of its underground powerhouses complicated and worthy of further study.For this reason,this paper studied the calculation method and control strategy of the natural ventilation of the underground powerhouse of the pumped storage power station through theoretical analysis,field investigation and numerical simulation.Firstly,the method and characteristics of the Z-transfer function method for calculating the internal heat conduction process of the tunnel rock were analyzed,and a fast calculation method for the heat and mass transfer process of deeply buried underground ventilation tunnels based on the Z-transfer function method was proposed.The calculation accuracy of this method when only sensible heat exchange occurs between the air and the inner wall and when air condensation occurs was analyzed,and its advantages in calculating the operating speed were discussed,which could provide a convenient way for the calculation of the natural ventilation of the underground powerhouse of the pumped storage power station.Secondly,since the natural ventilation power of the underground powerhouse of the pumped storage power station is mainly composed of wind pressure and thermal pressure,the influence of factors such as air humidity and outdoor vertical temperature gradient on the accuracy of thermal pressure calculation was discussed,and the influence of air condensation on the air temperature along the tunnel and the thermal pressure.The calculation method of natural ventilation power was proposed and verified by field test data.Through site investigation of several pumped storage power stations,the heat dissipation rate,and its change law in various operating conditions of the power station were analyzed and summarized.According to whether ventilation and air conditioning control measures are taken,it was proposed that the ventilation of pumped storage power stations could be divided into two schemes: natural ventilation with uncontrolled ventilation and on-demand ventilation.The calculation models and numerical solution methods of the two ventilation schemes were established.Furthermore,taking the Dawanshan seawater pumped storage power station as an example,the annual ventilation situation was calculated and analyzed,and the changes in natural ventilation volume and air temperature at the end of the traffic tunnel were summarized.Finally,an energy-saving control strategy for pumped storage power stations using natural ventilation was proposed.Divided multiple ventilation control periods according to the month and the operating conditions of the power station,and selected the ventilation plan for each control period according to the air temperature at the end of the traffic tunnel and the volume of natural ventilation.The dynamic changes of natural ventilation during on-demand ventilation based on simulation calculation were clarified,the calculation method of control measures was determined,and the natural ventilation energy-saving control strategy was designed for the underground powerhouse of Dawanshan seawater pumped storage power station,and its ventilation situation was analyzed.