Optimal Dispatch Strategy Of Longterm And Mid-Term Contracts For Concentrating Solar Power

In traditional power system,optimal dispatch of the power grid mainly focuses on centralized and coordinated dispatching.However,in recent years,with the continuous penetration of large-scale uncertain renewable energy,the increased forecasting difficulty of power generation makes the design of power system centralized control complex and the difficulty of power scheduling and operation cost increase exponentially.In addition,under the condition of insufficient system flexibility,a large number of reserve and auxiliary equipment requirements cause the additional economic cost of the system.Besides,in order to guarantee the reliability and economics of power supply in the power system,new requirements have been put forward to research on the complementary multi-source coordinated scheduling strategy to gain the maximum system profit.With the gradual improvement of the dispatching mode of thermal energy storage based concentrating solar power,concentrating solar power has already shown the similar regulation characteristics of thermal power,and concentrating solar power has the possibility to participate in the system’s optimal dispatching.This paper takes the development of concentrating solar power stations as an opportunity,and conducts indepth research on concentrating solar power modelling,coordination and optimization strategies,and the influence to the reduction of renewable energy uncertainty,to provide power and reserve benefits,and to participate in the operation of mid-long-term market mechanisms.First of all,in order to solve the problem of the increased difficulty of renewables forecasts locally due to the uncertainty of renewable energy penetration,it is proposed to coordinate the scheduling of concentrating solar power with the uncontrollable renewable resources such as wind power and photovoltaic with the aim to reduce concentrating solar power-wind power-solar power combined power generation bases.Based on the basic structure and working principle of the concentrating solar power,a simplified steady-state model is established.For the stochastic output characteristics of wind power and photovoltaic,the robust interval method is used to characterize the uncertainty intervals of wind power and photovoltaics.On the premise of satisfying the operation constraints of concentrating solar power stations,a robust optimization model for combined generator set scheduling is proposed to obtain the optimal power output interval of the concentrating solar power-renewables joint power generation base to achieve the robust operation scheduling of concentrating solar power stations.The optimization model is established as a two-stage robust optimization problem,and the improved column-constraint optimization algorithm is used to solve the model.The effectiveness of the robust optimization algorithm is verified by simulation examples.Secondly,in order to solve the problem of insufficient flexibility of the entire grid in the high penetrated power system and reduce the additional operating economic costs of traditional rotating reserves and auxiliary equipment,the adjustable concentrating solar power station is incorporated Into the power system,and a new method for optimal scheduling of stochastic unit commitment with concentrating solar power integration is proposed.A steady-state model which is suitable for the combination of concentrating solar power stations to the power system is established,and electrical heater devices are equipped to expand the operating space of concentrating solar power,and the parameter estimation is applied to determine the uncertainty scenarios of renewables.A two-stage stochastic unit commitment model is proposed with the aim to reduce the day-ahead power generation operation cost and the real-time dispatch cost.The two-stage model considers the generation optimization and the reserve plan simultaneously,and the chance-constrained method is proposed to optimize reserve plans.The effective operation and scheduling of the grid-connected concentrating solar power is realized.Through simulation examples,the effectiveness of the concentrating solar power station with thermal energy storage and electrical heater devices to provide energy and reserve benefits in the system is verified.Finally,in order to both ensure the reliability of the power supply of the power system,and gain the maximum system benefits considering the complementary multi-source scheduling with concentrating solar power,an optimal dispatch strategy that take into account the mid-long-term contracts formulation and scheduling decomposition of concentrating solar power is proposed to find the economic value of concentrating solar power,secure the reasonable benefits of renewable energy,and promote the consumption of renewables.In the mid-long-term contract electricity market,based on the analysis of the concentrating solar power-wind power-photovoltaic power generation uncertainty interval and the installed capacity of power generation bases which is proposed in Chapter 2,the mid-long-term market access conditions for the renewable energy power generation base are proposed.Based on the grid connected concentrating solar power unit commitment model in Chapter 3,the principle of thermal units and concentrating solar power mid-long-term contract declaration is put forward,and the rules of proportion formulation between renewables mid-long-term contract and spot market are designed.In addition,in order to realize the coordination mechanism between the mid-long-term contracts and the spot market,a mid-long-term contract decomposition curve is designed with the results of power output of renewables generation base in Chapter2 and the completion of the contract power.In the spot market,with the goal of maximizing system benefits,based on the actual buying and selling electricity price rules,a unit commitment model is designed that is suitable for the market-clearing in day-ahead market,which could realize the transfer of power generation rights between renewable energy and thermal power.The rules for mid-long-term contracts and the spot market profit calculation is formulated.Through case studies,the feasibility of formulating mid-long-term contract and initial spot market for concentrating solar power-wind-solar power combined generation base is verified.