| With the rapid development of China’s power industry and power system, power grids have been expanding. The establishment of global voltage and reactive power optimization system has become one of the key issues to ensure the safe and economic operation of grid. The automatic voltage control (AVC) system is an important means to improve the stability and to reduce net loss of the power grid. In AVC system, the second voltage system maintains stability of voltage in a certain partition. Therefore, the research on power grid soft partitioning method and the choice of several important notes is significant.Because inter-city power grid increasingly links, the scale of 220kV grid is much larger than 500kV grid, and the structure is much more complex. When the traditional method applying in 220kV power grid, there are problems such as:one needs to artificially determine the number of partitions and a whole partition contains no reactive power sources and the scale of the partitions is either too large or too small. To solve the possible problems in the partition process, integrating with original method, this paper proposes the partition method based on constraint-based clustering. By integrating the constraints into the clustering algorithm to modify the merger condition of traditional clustering algorithm and to limit the search process of clustering, the partition result can be obtained.Applying the constraint-based clustering method into the IEEE118 standard system and Liaoning 220kV system, the partition result is gotten. Comparing the results of this paper method and the traditional method, and the comparing result demonstrates that the result of this paper method is more reasonable.At last, in the foundation of partition method, this paper proposes the choice principle of the key note and the controllable pilot note and the critical note. And the choice principle is applying into the IEEE118 standard system and Liaoning 220kV system to obtain the results. |
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