Research On Daily Generation Scheduling Of Qing River Cascade Hydropower Stations In Response To Grid Load

Under the circumstance of the construction of Resource-saving and Environmentallyfriendly society, hydropower met a new development opportunity. Large-scale river-based hydropower companies in China have gradually established their own Cascade Dispatch Center to manage the water resources synthetically, in order to make full use of the hydropower compensation between the cascade hydropower stations to achieve the maximum efficiency via daily generation scheduling. However, with the promotion of the strategy on “Clean and Low-carbon” energy system, hydropower will take charge of more tasks to maintain safe and stable operation of the grid because of excellent ability in adjustment. So it is more close to the real situations to consider the requirement of the stable and safe operation in daily generation scheduling. Thus, intensive research on the influence of grid load on daily generation scheduling is not only significant for the process of stations but also for the safety level of power grid.Taking Qing River Cascade hydropower stations into account, this article researches on grid safety constraints, power generation efficiency optimization and peak-shaving optimization based on the requirement of power grid. And a new thought of modeling in daily generation plan is proposed combining unit-level optimization with station-level optimization. Moreover, efficient and reasonable solving methods for two levels are respectively raised. Therefor, all above provides the theoretical basis and technical support for the daily generation scheduling of Qing River Cascade considering the power grid security constraints. Meanwhile, the Qing River Cascade daily scheduling system is designed and developed to provide decision-making platform for scheduling personnels. Now a brief scheme is summarized as follows:(1) After analyzing the situations when Qing River Cascade answered the power grid commands, especially Geheyan station with multiple transmission sections, main grid safety constraints are summarized, including voltage regulation, halt reserve, spinning reserve and limit of transmission section. According to the regulations and experiences of Qing River Cascade Dispatching Center, the constraints are abstracted in mathematical expression form and determine the range of constraints.(2) Based on the mathematical expressions of constraints, take the further exploration on unit load distribution and set up the model considering grid constraints with the objective of minimum flow consumption. And two distribution methods respectively based on the refined control strategy and the whole characteristics fitting surface are proposed to mend the traditional solution which is difficult to deal with complex constraints and has low efficiency. The result of application to the units of the Qing River Cascade shows the thought of modeling can improve the unit energy utilization efficiency in the condition of grid safety constraints and two proposed methods are steady to handle the grid safety constraints with high efficiency. Thus, it can provide guidance to improve the efficiency of power plant power generation under the premise of meeting the grid security constraints.(3) Research on the daily generation scheduling considering peak-shaving, and establish the models of daily generation plan in two relevant modes, consisting of power generation control mode and level control mode. At the same time, two methods are proposed based on unit-level optimization. One is heuristic successive load shedding for power generation control mode, which takes the power of initial curve as heuristic information to deal with constraints for the adjustment of daily generation scheduling. The other is hybrid progressive particle swarm optimization algorithm for level control mode, with POA compressing descending dimension and solution space of PSO. The daily generation scheduling simulation of Qing River Cascade shows that the entire thought of model can balance the efficiency of power generation and peak shaving, and the proposed methods can improve the solving accuracy and result, as well as reducing the calculating time. It can provide a new method for the daily generation plan of the Qing River cascade in response to grid load.(4) Integrate all achievements above, and develop the Qing River cascade daily scheduling visual system. It is designed according to the “Internet plus water conservancy” and achieved by the way of single page web application and HTML5 offline technology to make the browser more like a powerful client and realize online-offline integrated development. Moreover, build the responsive web front frame with MVVM design mode to suit the trend for mobile Internet, and take advantage of SSH combinative framework to establish backend structure in order for the stability and scalability. The thought of system design can provide reference for the information construction of Qing River cascade hydropower or even larger-scale stations.