Coordinated Optimal Dispatching Strategy For CSP-PV-W Combined Power Generation System Considering Source-Load Uncertainty

Wind power and photovoltaic power generation are developing rapidly,and their on-grid electricity is increasing continuously.As a result,the energy structure has undergone significant changes.Affected by its own random volatility,large-scale integration of wind and photovoltaic power into the grid is likely to cause power fluctuations in the power system,which increases the difficulty of grid dispatching and new energy consumption.Since the Concentrating solar power(CSP)station is equipped with a thermal energy storage(TES),it has a good output regulation capability.Therefore,the flexible and adjustable cha racteristics of the output of the CSP station can be used to balance the fluctuation of the wind and photovoltaic output,and reduce the impact of the fluctuation of the output of the new energy on the power grid.(1)The basic principle and system structure of wind power generation,photovoltaic power generation,CSP power generation and electric heater(EH)are introduced.The heat storage and release principle of EH and the energy conversion characteristics of the CSP power station containing TES combined with the resistance electric heating furnace were analyzed.It provides a theoretical basis for the follow-up modeling of the subject.(2)In view of the problem of high-efficiency consumption of large-scale grid-connected scenery.Firstly,use the electric heating capacity of the EH to absorb excess wind and photovoltaic output,and act as a backup power supply for the CSP power station to increase its regulation capacity.Considering the system’s requirements for flexibility and diversity of backup,use the superior bidirectional regulation capability of CSP power station and EH to provide partial backup;Secondly,aiming at the maximum daily output of new energy power generation and the minimum system operation cost,an optimal dispatch model of the combined solar thermal-photovoltaic-wind power(CSP-PV-W)generation system considering EH is established.Day-ahead dispatching is based on wind and photovoltaic forecast output and load demand,and seeks the optimal dispatching output of thermal power and CSP power plants.Taking the day-ahead dispatching results as the input variable of daily rolling,combined with ultra-short-term wind power,photovoltaic and load forecasting data,formulating an intraday dispatching model,and then using the fast response characteristics of CSP power plants to cooperate with thermal power units to balance wind-photovoltaic forecast errors;Finally,the calculation example results show that the proposed model can effectively improve the level of new energy consumption and reduce the peak regulation pressure and standby pressure of thermal power units.(3)Considering the uncertainty of high proportion of new energy and load,a two-layer optimal dispatching model of the CSP-PV-W generation system is constructed.Equivalent wind power and photovoltaic output as negative loads,the upper layer optimization model takes the minimum expected value of the residual load variance of the system as the objective function,and the lower layer model takes the lowest total operating cost of thermal power units and CSP power stations as the objective function.Firstly,the uncertainty of wind and photovoltaic output forecast is described by a definite multi-scenario analysis method.Intraday wind and photovoltaic and load uncertainty is charact erized by trapezoidal fuzzy number equivalent model,and the model is solved by clear equivalence and setting different confidence levels;Secondly,the remaining load of the system is determined based on the wind and photovoltaic output forecasting scenar io set,and the optimal scheduling is carried out in combination with thermal power and CSP power stations.Taking the results of the day-ahead dispatch as a reference to forecast the wind,photovoltaic and load during the day,and use the forecast data t o represent the wind,photovoltaic and load with a quadruple of trapezoidal fuzzy parameters,and carry out the optimal scheduling within the day,so as to determine the actual dispatch output and rotating reserve of thermal power units and CSP power plant s.Finally,the numerical example analysis verifies that the model can effectively improve the consumption of high proportion of new energy such as wind power and photovoltaics.