Research On Model And Algorithm Of Power System Daily Generation Scheduling

Generation scheduling is an important part of energy-saving optimal scheduling. According to the national call for the establishment of conservation-oriented society, it is of great social and economic significance to reduce operation cost by generation scheduling optimization. Consideration to economy and safety, generation scheduling is generally divided into two stages: making generation schedule and security checking in practical system. Based on this point, the model and algorithm of daily generation scheduling have been studied in this paper; and power flow algorithm, the important part of security checking, has also been studied to enhance the security checking speed. The contents presented in the paper are as follows:Firstly, an optimization model for daily generation scheduling is established considering the unit regulating times as one of the targets, and an improved multi-population genetic algorithm (GA) based on heuristic rules is proposed to solve the problem. Consideration to minimizing total generation cost and reducing generator unit regulating times, system load curve optimizing division and unit output curve approximate merging are adopted to reduce effective time periods of system load and unit regulating times respectively. To enable better global optimization ability of the algorithm, the system curve is divided several times to form several equivalent curves with different effective time periods, and then multi-population strategy of GA is adopted to collaborative optimization. Finally, the appointed fine adjustment unit is used to undertake the power imbalance appeared within the curve equivalent progress. Moreover, according to the constrains in the optimization model, especially the unit energy contract and power balance as two cross constrains, suitable individual initialization and feasibility adjustment strategy are proposed to ensure the optimization searching in the feasible region. The above measures enable effective solving of the optimization model, and the unit output should be more stable and efficient.Secondly, during the study of power flow algorithm, the important part of security checking, an countercurrent-layered topological search method and layer-decoupled power flow algorithm for complex networks are proposed based on the characteristic of meshed network and radial branches coexisting in the high voltage grid. Through topological search, the original grid is disintegrated into two parts with common boundary nodes, a main meshed network and some radial subnets, and the branch hierarchy of the radial subnets is formed automatically. Then, the radial subnets are assumed to be equivalent to the nodal load of the main meshed network, and the boundary nodes voltage of the main meshed network equivalent to the supply voltage of the radial subnets. The fast decoupled method and the back/forward sweep method are employed to calculate the main meshed network and the radial subnets alternately, and the integrated calculation is realized by the alternate modification of the equivalent load and equivalent voltage. The back/forward sweep calculation for radial subnets is made layer-by-layer according to the branch hierarchy.The model and algorithms presented in this thesis have been verified by IEEE standard systems and practical power systems, the simulation results proved that they are correct and effective.