Research On Sustainable Operation Of Solid Electric Thermal Storage System To Improve Wind Power Integration

With the fast development of wind power in China,the wind integration has become increasingly prominent,and the wind power in the north has been seriously abandoned.In this context,the technology of thermal storage to use wind for heating has been widely adopted in the north.In this paper,three aspects of research on key technologies of using thermal storage to reduce wind curtailment are carried out:economic technology modeling and capacity allocation of solid electric thermal storage system,sustainable operation mechanism of using thermal storage to reduce wind curtailment,and joint thermoelectric optimization scheduling with thermal storage.The specific research contents are as follows:1.Established an economic and technical model of a solid electric thermal storage system.The material selection and design of solid electric thermal storage system are described,including thermal resistance selection,thermal storage medium design,heat transfer design,thermal insulation design and control system design.According to the existing solid electric thermal storage system,an economic and technical model is established.The economic model of a solid electric thermal storage system considers the total investment cost and operating cost.Based on the one-dimensional heat conduction equation,the first-order charge and discharge heat model of the solid electric thermal storage system is established.A simplified method for discrete charge and discharge model is obtained by using the differential method.Through the actual engineering case,the cost analysis,energy utilization efficiency analysis and model accuracy verification of the solid electric thermal storage system are carried out using the technical economic model established in this paper.A basic overview of abandoned wind heating is introduced,including the thermal storage installation location and the heating mode.According to the heating mode and cooperation mode,the optimal capacity planning model for solid electric thermal storage considering the characteristics of abandoning wind is established.Based on the historical data of Liaoning abandoned wind,the research on thermal storage capacity allocation was carried out in a province of Liaoning Province and a certain district in Dalian.It was found that the allocation of solid electricity storage heat to reduce wind curtailment has good economic benefits.2.Proposed a sustainable market operation mechanism for thermal storage and wind farm.Introduced the northeast peaking auxiliary service market policy,and found that abandoned wind heating enterprises can provide peaking services for wind farms and gain profits.Considering the uncertainty of the abandonment of wind power itself,this paper proposes a sustainable market operation mechanism combining long-term bilateral transaction contracts with short-term centralized transactions.Long-term bilateral trading contracts consider the wind curtailment price,total amount,and unbalanced electricity.In the short-term centralized trading,the wind farm adopts the Cournot model quotation with the bid deviation penalty mechanism,and the thermal storage enterprise adopts the dynamic inverse demand function to bid.3.A large-scale thermoelectric optimization scheduling method based on pre-evaluation of abandoned wind is proposed,including two time scales before and after the day.Based on the pre-evaluation model of wind curtailment before the day,the operating scheduling optimization model of the thermal storage system was established,and the curve of the thermal storage enterprise to reduce the wind curtailment was obtained,and the part of the wind was bidded.Based on the intraday wind curtailment correction model,an intra-day optimal scheduling model of the thermal storage system is established to obtain reduced wind curtailment sequence.A microgrid thermoelectric optimization control method based on two-layer coordinated control is proposed,including a dispatching layer and an intra-day real-time coordinated control layer.Considering the two types of energy storage:thermal storage and battery energy storage,the optimization model of the microgrid day-time dispatching layer is established to calculate the output of each conventional unit.Considering the two microgrid operation modes of grid-connected and isolated,a coordinated control strategy for thermal storage and battery energy storage in the real-time layer is proposed.In the grid-connected mode,the main effect of thermal storage and battery energy storage is to reduce the power fluctuation of the grid-connected point;in the isolated mode,the main effect of thermal storage and battery energy storage is to ensure the system frequency and voltage stability.