Research On Optimization Of Pumped Storage Unit Start-up Under Low-head Conditions And Predictive Control Considering Uncertainty Of Wind Power

With the depletion of fossil energy and the increasing environmental pollution around the whore word,large-scale development of clean and renewable energy has become the only way for the sustainable development of global energy.Wind power energy is an important clean and renewable energy with abundant reserves,short construction period,good economic and environmental benefits,and huge development potential.However,wind power energy is greatly restricted by natural conditions,the output of wind power energy has more obvious intermittent.If it is directly connected to the grid,it will inevitably affect the power supply and demand balance of the power system and reduce the power quality.With the advantages of fast start-up and shutdown and flexible working condition conversion,pumped-storage units(PSUs)can quickly respond to changes in the power of wind energy.In this paper,the complex nonlinear characteristics of the PSU and the random disturbance of wind power have been considered and builds a simulation model of the pumped storage-wind power hybrid system.As the energy storage link in this system,the transition process control of the PSU is of great significance to the stable operation of the system.Taking the PSU with one tunnel-two unit arrangement as the research object,the influence of the start-up interval and the hydraulic interference between units on the startup transition process when the units are successively started under low-head conditions is studied and analyzed.To improve the regulation performance of the unit’s successive startup under low-head conditions,research is carried out around the multi-objective optimization of the successive start-up control strategy.For the pumped storage-wind power hybrid system,the predictive control strategy is introduced,study on predictive control of the hybrid system is carried out under random disturbances of wind power energy output.The results have important theoretical significance and engineering value for ensuring the efficient operation of pumped storage units,improving the control quality of pumped storage-wind power hybrid system,and increasing the utilization rate of wind energy.The main research of this paper is summarized as follows:(1)Research on modeling of pumped storage-wind power hybrid operation system.The improved Suter transformation method is introduced to deal with the full characteristic curve of the pump-turbine,and an interpolation model for the full characteristic curve is established;fully consider the complex boundary conditions of the water diversion system and the typical non-linear links in the actuator,establish a refined simulation model of the unit regulation system.For the wind turbine,an aerodynamic model is established,and interconnect with the PSU to build a pumped storage-wind power hybrid power system.(2)Analysis of the influence of the interval time on the quality of the unit start-up transition process control.Aiming at the PSUs with one tunnel-two unit arrangement,the impact of interval time and hydraulic interference between units on the control of the unit’s successive start-up transition.Analyze the correlation characteristics between the hydraulic interference between units and the time between successive start-ups under low-head conditions.(3)Study on the optimization of successive start-up control of PSUs under extreme conditions of the low head.The speed rise time and ITAE of speed are selected as the optimization objectives,which can simultaneously take into account the quick and stability of the start-up process of the two PSUs.At the same time,the dynamic performance indicators of the two units as the constraint conditions have been fully considered,and the MOASA optimization algorithm is introduced to optimize the control law of successive start-up of PSUs under low water-head conditions.Besides,to further improve the control performance,fractional PID control is used to replace the traditional PID controller.(4)Research on predictive control of pumped storage units considering the uncertainty of wind power.Focus on the regulation and control of the pumped storage-wind power hybrid system,the predictive control strategy is introduced to carry out the predictive control of the PSU considering the uncertainty of wind power is carried out.The results have important reference value for improving the regulation performance of the hybrid power system,alleviating the impact of random fluctuations in wind power energy on the grid,and improving the compatibility of the grid with wind energy and the utilization rate of wind energy resources.