Study On Power Generation Operation Of Multi-Reservoirs Based On Succession-Level Optimization Method

Hydropower is a cheap and clean renewable energy and takes up a considerable proportion in energy structure of China and plays an important role in power system.With the rapid development of economy and society of China,the energy shortage and environmental pollution problems are aggravated day by day.Rational use of hydropower energy and producting optimal operation of it have significant meaning for improving benefits,alleviating energy crisis and for energy saving and emission reduction.Generally speaking,hydropower dispatch experiences two stage,namely stage of experience-based dispatch with conventional methods and stage of optimal dispatch with optization theory and algorithms.The conventional dispatch is simple and intuitionistic,but the results tend to be conservative and has large room for improvement.However,optimal dispatch can exploit the whole potential of hydropower system better and is an important subject with great economic benefits.This paper conducts a research on some important problems in the area of power generation operation of reservoir and multi-reservoir.The main contents and contributions are as follows:(1)For the ?curse of dimensionality? problem of DP(dynamic programming)in multi-reservoir optimization and the ?pseudo optimal solution? problem of POA(progressive optimality algorithm)and DPSA(dynamic programming successive approximation),this paper presents a succession-level optimization method to solve the multi-reservoirs optimization problem.The presented method integrates the advantages of POA,DPSA and DDDP(discrete differential dynamic programming)to reduce the dimensions of state space of the optimization problem.Meanwhile,three improvement measures are presented to guide the algorithm to jump out of the standstill state when arriving at the boundary of the constraints,by which the ?pseudo optimal solution? problem is avoid and the quality of the solution obtains improvement.The classical four reservois and ten reservoirs problems are used to test the performance of the presented method and the results demonstrate the feasibility and effectiveness of the method.(2)This paper conducts a study on the difficulty and irrational phenomena met in application of the minimum energy consumption model for load distribution of cascade hydropower stations.By analysing the energy changing relationships of cascade reservoir,the reasons why the energy consumption calculated according to the objective function of the model is related to the state transition path of reservoir and the reasons why the results obtained through evaluating the load distribution schemes by the model don't match reality are found.And on this basis,the minimum energy consumption model is improved by taking the influences of energy losss of inflow and head loss of tail water on energy consumption of reservoir into consideration.The simulating results show that the improved model can express the enenrgy consumption of cascade reservoir more accurately.The improved model has ractical application value to solve the load distribution problem of cascade reservoirs.(3)The succession-level optimization method is used to solve the multi-reservoir optimization problem of Hunan power grid and a dispatching function model for the multi-reservoir system is built.The multivariate linear regression method is used to solve the dispatching functions of each backbone reservoir in the multi-reservoir system.The simulating results demonstrate the rationality and availability of the dispatching functions.