| Energy-saving power generation dispatch is a major move in the power industry to promote to complete the strategic goal of energy conservation and emissions reduction. In China, power energy structure is given priority to with thermal power and hydroelectric. The key of energy-saving power generation dispatching is to research the effective hydrothermal scheduling method, in order to fully embody the principle of safe, economic, energy conservation and environmental protection. Different from the grid where thermal power is dominated, the characteristic of the grid with rich hydropower is that hydropower is plentiful, and the thermal power and hydropower have very good complementarity in it. The potential of energy conservation and emissions reduction in the grid with rich hydropower is considerable, so to carry out energy-saving power generation dispatching and control research of the rich hydroelectric power grid has important theoretical significance and engineering practical value for saving fossil energy and promoting the completion of the national energy conservation and emissions reduction targets. This research arises under the background of key science and technology problems of short-term operation and real-time control in the grid with rich hydropower. Based on fundamental theories of Operations Research, Science of Hydropower Energy and Combinatorial Mathematics, this research takes the grid with rich hydropower, such as Yunnan power grid and Guizhou power grid as its engineering backgrounds and takes energy-saving dispatching order of power generation as its main line to carry out large-scale small hydropower generation scheduling, devastating cascade hydropower station group of load optimization scheduling, thermal power system scheduling and the modeling and solving method of cascade AGC coordinated optimization control. The author has made some achievements for the theoretical significance and engineering practical value and these achievements can be wrapped up by presenting four points:Firstly, by analyzing the characteristics of small hydropower and operation rules, large-scale small hydropower generation scheduling method is proposed with the consideration of multistage section safety constraint. This method regulates the processes of making plans, abandoned the traditional way of planning models solely by related scheduling institution and carried out making plans by multi-institutions or related department for power generation. Load distribution method based on dispatching order and custom order of peak regulation are adopted to fully display ability of small hydropower in power grid in peak load regulation. The description and analysis of complex nested multistage interconnection structure of the small hydropower is based on the set theory. Besides, following the principle of the fair scheduling, transfinite section plan correction and proofreading method is designed to eliminate risk of stable operation of power grid caused by transmission in transfinite section. The above-mentioned method has been used in the management technology support system of Yunnan power grid including1789small hydropower stations, where the effectiveness has been verified available by the practical engineering.Secondly, with regard to the increasing gap between power grid load peak and valley in China and the problem of peak regulation, the maximum electricity short-term peak regulation model of complex hydroelectric power stations is established. This model is to minimize the maximum value of system remaining load. For the sake of optimal solution, the adoption of aggregate function replaces of optimal goals. As for the distribution and combination of the present power stations and power unit in extra-large watershed cascade hydropower stations, the regulation objects has shift to the combination objects of power stations as well as power units. A series of methods are adopted, including improved cutting load method, coordinate alternation method, progressive optimal algorithm, penalty function method and optimization by heuristic strategy. The aim is to make full use of large hydropower to regulate peak load and adjust remain system load to efficient operation of thermal units. The calculation results from Wujiang cascade hydropower stations indicate this model takes a good effect on peak regulation. Therefore, it is a feasible way to solve the existing problem.Thirdly, with thermal units in rich hydropower grid as the studying object, the minimum coal consumption generation scheduling model is constructed of thermal power system. A hybrid method of incorporating dynamic unit commitment into equal incremental principle is proposed in this paper. This model introduces duration period requirements in order to prevent thermal power unit from frequently fluctuating during output. Based on the unit power generation sequence, the dynamic unit commitment algorithm is designed so as to let the equal incremental discharge criterion meet the needs of sustained period of time demand for energy conservation unit commitment during the process of dynamic load allocation. With the adoption of heuristic iterative modification strategies, the traditional equal incremental principle is improved in order that the allocation results meet the needs of unit commitment complicated inequation limits including operation ramp rate limit, output limits constraint and generation variation constraints. This method has been applied to energy-saving power generation dispatch decision support system of Guizhou power grid. The practical scheduling results in typical day of flood season and dry season in Guizhou power grid has been taking good effect in energy conservation and proved to meet the practical operation needs of power grid.Fourthly, automatic generation control (AGC) is the essential condition to realize short-term scheduling. Relying on cascade AGC coordinated optimization control of extra-huge basin, the model of coordinative control power grid AGC and cascade AGC with taking into consideration of the constraints in power grid safety of AGC, vibration area, adjusting rate and unit commitment is built. Energy of day-ahead generation schedule of cascade stations is used as the control target, In view of the key problems of models on load distribution among factories, the joint avoidance with vibration area, stability of overload control, and relative proportion of water rate is brought in and grid coordinate with cascade AGC control strategy is proposed and connecting with the combination of mathematical theory, the coordinative control strategies of power grid AGC and cascade AGC is put forward systematically with the application of combinatorial theory in math. The control strategies include AGC input sequence method, unit commitment strategy, load distribution method among factories, the joint avoidance strategy with vibration area and stability of overload control strategy. The simulative closed-loop running results of cascaded AGC of Wujiang river main stream show that the proposed strategy is effective and it can better realize the organic link between the real-time online control and the short-term scheduling, which in turn can satisfy the AGC needs of security, timeliness, practicality and economics.Finally, a summary is given and some problems to be further studied are discussed. |
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