Coordinated Optimization Of Water-level Regulation Of Cascade Hydro-power Stations,Mid-and Long-Term Maintenance Schedule And Transmission Schedule

The reverse distribution of energy load in China determines that China's energy will flow "from north to south,from west to east".To cope with this basic pattern,electricity transmission across different regions and provinces based on UHV AC and DC has become the focus of the development of power grid.Currently,DC projects like Binji DC,Jinsu DC and Fufeng DC transport the abundant supply of hydro-power from the southwest to the east.Since the hydro-power being transported include not only those from large-scale river basins but also the large number of run-of-river small hydro-power of the source provinces(usually in the form of hydro-power outward power transaction).Most of the former are equipped with annual or quarterly regulating reservoir.So coordinating the mid-and long-term reservoir regulation with the transmission of numerous run-of-river small hydro-power is one of the effective ways to improve the efficiency of hydro-electronic power and power grid.On the other hand,due to the lack of load demand of the source power grid,all the power generated need to be transmitted to other regions,which weakens the structure of the source power grid.Since electricity usually completes its transmission traveling through certain key cross sections and then gathering at the converter station,these cross sections become the obstacles to electricity transmission.Although the transmission limit of the cross sections is determined by the operation mode,the load demand and the mode of operation,the maintenance schedule has a direct influence on the transmission power of the section.Where conditions permit,it is significant for the utilization of hydro-power to coordinate the maintenance schedule,the nature of the primary energy and power transmission schedule.This paper seeks to resolve the coordination between river basin hydro-power schedule(which involves water storage in reservoirs and the regulation of the fluctuating of water level),transmission schedule and power grid maintenance,to uncover the strategy to coordinate the three in mid-and long-term,establish a model and determine the best coordination plan based on the model.The major content and results are as follows:(1)This thesis quantifies the influence of reservoir water level and river flow between two power stations on power output and energy storage capacity,analyzes the characteristics and models of coupling relationships like the ratio of power generation between two groups of plants and the ratio between water storage and generating capacity,and proposes the methods to describe the coupling relationship between cascade power stations.(2)This thesis also analyzes the key variables and parameters of cascade hydropower water level regulation,,maintenance schedule and transmission schedule,puts forward a coordinated strategy of the four with transmission schedule as the core that could be adapted to different variables and parameters.(3)The object function and constraint condition of the mid-and long-term water level regulation of cascade hydro-power station,transmission schedule and maintenance schedule are determined,and the methods to build the model of joint coordination with generation schedule as the center.(4)The algorithm of joint coordination is worked out;the ratio of power generation in cascade power stations is set up,taking into consideration the reservoir water level,the water flow between hydro-power stations and power generation capacity to;application of the model to the large scale hydro-power transmission in Sichuan is analyzed to verify its correctness and effectiveness.This thesis provides the calculation tools for the joint coordination between mid-and long-term water level regulation of large-scale river basin hydropower,transmission schedule and maintenance schedule,which gives full play to the function of river basin hydro power stations to generation power using water flow,coordinates the hydro-power of different flexibility and of different regulating institutions,improve the efficiency of large-scale power transmission channel and the utilization of clean energy.