Research And Application For Short-Term Peak-Shaving Dispatch Of Large-Scale Hydropower Stations In Huazhong Power Grid

Along with the economic development, the adjustment of industrial structure and sustained growth of new energy resources capacity, the peak-valley difference growth of main regional grids and most of the provincial grids overtakes the load growth. In order to ensure the safe and stable operation of grid, it’s very important to reduce the peak-valley difference. Meanwhile, hydroelectric unit is one of the best peak-shaving power source because it starts and stops quickly, runs flexibly and also has strong climbing ability. Therefore, it’s urgent to solve the problem that how to apply hydropower capacity to peak- shaving efficiently and ensure the safe and stable operation of grid. In order to make sure the regional grids run stably and make full use of hydropower resources, short-term peaking-shaving dispatch of hydropower stations must be researched in a deep-going way, which has very important theoretical significance and engineering value.In this article, eight hydropower stations in Huazhong power grid are research objects. As these stations need to translate power to multiple grids, and their translating range and ratio are different, it’s needed that consider all stations’ capacity and grids’ running conditions stably. In order to provide secure theoretical guide and technical support, short-term peaking-shaving dispatch of large-scale hydropower stations in Huazhong power grid must be researched. Now a brief scheme are summarized as follows.(1) After analyzing the present situation of Huazhong power grid that there are a great deal of stations and there stations distribute in many different provincial grid and river basin, this article divide this problem into “single-station to multi-grids” and “multi-stations to single grid” problems to modeling and solving them, using a rule names “control by station’s level, and calculate globally”, which mainly means these stations are divided by administrative area, river basin and power-translation range. This rule can reduce the dimension of decision variables and constraints without affecting the accuracy of calculation.(2) Because of huge discrepancy in load level and load characteristics, all grids’ peakshaving demand need to be meet to dynamically response frequency changes of grid load in the problem that single hydropower station need to supply power to multiple grids. Therefore, a multi-grids peak-shaving model is built, to solve the model, a heuristic short-term peak regulation method is established, of which objective is to minimize and smooth the residual load of power grids. Applying the proposed method to the short-term scheduling of Ertan hydropower station, the application results show that this method can not only make full use of peak operation ability, but also give consideration to the load characteristics of power grids, which provides an effective approach for the short-term peak regulation problem in the case of single station supplying multi grids.(3) In the problem that multiple hydropower stations need to supply power to single grid, because these stations have daily regulation capacity, not only contact with water transfer, but also have many comprehensive utilization demand, it’s a high-dimension problem in short-term dispatch. Therefore, from the aspect of large-scale hydropower stations, a short-term peakshaving model of “multi-stations to single grid” problem is built, using a DDDP based on asymmetric self-adaptive corridor method to solve it, in order to avoid the problem that the computational efficiency and accuracy of existing method is very low, which can reduce the width of DDDP corridor, decreasing the calculating time and improving the accuracy. Applying the proposed method to the short-term scheduling of Qingjiang cascade stations, the application results show that this method can not only make full use of peak operation ability, but also avoid abandoning unnecessary water.(4) Based on the above research results, the “hydro-thermal of Huazhong power grid combined dispatch application system” is developed by a framework named Rich Internet Applications(RIA) with Java FX, which is to provide decision support for short-term dispatch of hydropower stations in Huazhong power grid. This application system can invoke fully client computer’s calculate ability, and reduce the transfer pressure of network and calculating pressure of server, meanwhile, it has more rapid response speed and more abundant Human-Computer Interaction elements than web applications.