Study On The Assessment Of Power-generating Benefits From Wujiang Cascade Hydropower Stations Integrated Operation

With the development of the reform in the electric power system, the separate of factory and network, and the improvement of the electricity market, to achieve the power generation benefit maximization under the security restriction of hydropower station, thus, improve the level of the economic operation is the critical work of the hydropower station. The economic operation of the hydropower station not only include of formulating a reasonable operation scheme, also need the support of management, such as benefits assessment.The water resources and hydropower resources in Wujiang river basin is abundant, and the basin is not only one of 13 large hydropower base in our country, also is one of the main power source of "Western to Eastern" of the exploiting in West. The cascade hydropower stations is exploited by Wujiang stem river, which is consist of Hongjiadu, Dongfeng, Suofengying, Wujiangdu, Goupitan, Silin and Shatuo, its combination of operation performance is complex, and its main exploiting task is given priority to electricity, so its direct operation performance is power-generating benefits. The paper took Wujiang cascade hydropower stations as example, based on the intention of commanding the actual operation level and how to achieve to maximize the power-generating benefits, carried on the power-generating benefits assessment research. The main research work and achievements are as follows:(1) With the joint operation of cascade hydropower stations, the problem that the limitation in the application of conventional power-generating benefits assessment method arose in the work of power-generating benefits assessment. After demonstrating the capacity of the potential optimization method, the paper put forward on the basis of conventional method, calculate the power output and completion rate by an optimal operation model for cascade hydropower stations with main factors influencing power output as constraints, then a comprehensive assessment of cascade hydropower stations is achieved. From the assessment results under these two power-generating benefits assessment methods, the paper will commander the real managing-operation real.(2) Aiming at the problem that in power-generating benefits assessment, the output coefficient was often assumed as a constant for easy calculation and improving the calculation speed, which will seriously affect the calculation accuracy and even lead to a false result, in the paper, based on observed data of hydropower station, and after an analysis between water head and output coefficient, a new output coefficient curve was formulated at the basis of the moving-average method, then it was applied in the station power simulation, and the results show the curve is reasonable and applicable, so it can be used as a valuing method of high accuracy. Then, this curve was used in the power-generating benefits assessment.(3) In order to complete the power-generating benefits assessment of cascade hydropower stations, the research on the algorithm for solving the joint optimal operation model of cascade hydropower stations is studied. Through a comparison and analysis of advantages and disadvantages of traditional optimization algorithm and swarm intelligence algorithm, the paper used a mixed algorithm of swarm intelligence algorithm and progressive optimization algorithm to solve the model. On the swarm intelligence algorithm side, particle swarm optimization algorithm and particle swarm optimization algorithm are studied and improved by embedding downhill simplex method and the logistic chaotic sequence, respectively. The example calculation results show that the improved algorithm on the precision and convergence rate have been improved significantly.(4) Both conventional and potential optimal power-generating benefits assessment method are used to assess Wujiang cascade hydropower stations, during the assessing period, the power-generating operation level is medium, and the increased power output is 1.88 billion Kw·h in conventional power-generating benefits assessment, the power-generating operation level is excellent, and there is still 2.69 billion Kw·h potential optimal space in potential optimal power-generating benefits assessment. Combination of two kinds of power-generating benefits assessment methods shows that power-generating operation level of Wujiang cascade hydropower stations is preferable, and runoff, runoff prediction and the safe operation of the power grid is the main influence factors of Wujiang cascade hydropower stations. The assessing results objectively reflect the power-generating operation level of Wujiang cascade hydropower stations. Under the condition of water and constraints, the build joint optimal operation model will output the optimal operating process line, this line can provide wujiang cascade hydropower stations for achieving maximum power-generating performance with potential optimal approach, it also offer technical supports to improve the level of economic operation furtherly.