Research On The Optimization Model Of Inter-provincial Mid-and Long-term Power Purchase And Sale Strategy For Hydropower Enriched Power Systems

The electricity market reform in China is being continuously and orderly promoted.Hydropower enriched power systems such as Sichuan and Yunnan province are facing the market situation of ’power surplus in the wet season and power shortage in the dry season of power supply and demand in the province’ and there are many difficult questions in the construction of the electricity market.The power source structure and electric power system of South American countries such as Brazil,Chile and Peru are similar to those of Sichuan and Yunnan,and their cost-based power pool market mode can be used for reference.However,South American countries have neither formed a regional electricity market nor conducted cross-market electricity transactions.China is currently carrying out the construction of provincial and inter-provincial electricity markets at the same time.There is an urgent need to achieve optimal allocation of power generation resources through provincial and inter-provincial electricity spot transactions and mid-to-long-term power transactions.In this context,it is of important research significance to research the optimization model of inter-provincial mid-and long-term power purchase and sale strategy for hydropower enriched power systems based on the cost-based power pool market mode.This paper proposes an optimization model of inter-provincial mid-and long-term power purchase and sale strategy for hydropower enriched power systems.The optimization model realizes the coordinated optimization of inter-provincial mid-and long-term power purchase and sale transactions and the provincial electricity market,and can provide a theoretical method for hydropower enriched power systems to formulate time-phased inter-provincial power purchase and sale transaction strategies.The specific research content is as follows:1.Analyze the operating characteristics of hydropower enriched power systems,and discuss the electricity market mode in hydropower enriched power systems.This paper describes the main characteristics of hydropower enriched power systems through the analysis of output characteristics,regulation performance of a single hydropower station,and the operating characteristics of the cascade hydropower station.The applicability of typical electricity market modes all over the world is briefly analyzed,and the practical experience of the Chilean electricity market is comprehensively reviewed.2.Aiming at the hydropower enriched electricity market adopting the cost-based power pool market mode,a mathematical model for optimizing the inter-provincial mid-and long-term power purchase and sale strategy is proposed.The overall optimization model takes the cost-based power pool market mode as the application premise,introduces the cost and revenue function of the inter-provincial power purchase and sale transactions,and takes minimizing the provincial comprehensive power purchase cost as the optimization objective(taking the power sale revenue as the negative power purchase cost)to construct long-term optimization model and mid-term optimization model respectively.Based on the relationship between the storage electricity of the equivalent hydropower station and the reservoir capacity of the actual hydropower station,the expression of the dynamic coupling between the optimization models is deduced.Sort out the inter-provincial mid-and long-term power purchase and sale strategy optimization process,design the software functional architecture,and provide ideas for the development of the corresponding technical support system.3.Derive the solving algorithm of the model and construct a calculation example to verify the optimization model.The stochastic dual dynamic programming algorithm is used to solve the optimization model,and the method of using the dual problem to construct the future cost function is derived.The optimization model proposed in this paper is verified by an example.The results show that the proposed model can optimize the transaction plan of power purchase and sale for hydropower enriched power systems.It seeks to minimize the power purchase cost of provincial customers and maximize the benefits of power export while meeting the provincial load demand in the dry season and the dry year.The model can also give full play to the utility of clean energy,promote energy saving and emission reduction.