Decoupling and dimension reduction method for distribution system security region

The application of the security region methodology in a practical distribution system with large scale normally requires large computer memory and high computation time. To overcome this problem, this article proposes a decoupling and dimension reduction method, which can significantly accelerate the calculation of distribution system security region (DSSR) and is important for the application of the DSSR theory in large-scale distribution systems. First, the definition of DSSR dimension reflecting the size of solution space and the time complexity is proposed. And the solution algorithm for DSSR dimension is also given. Second, a decoupling and dimension reduction method suitable for the analysis of DSSR is proposed. Following the method, an incidence matrix can be obtained from the DSSR expressions, which can be further divided into multiple block matrices. According to the feeder combinations of the block matrices, the distribution system can be decoupled into multiple sub-networks for more efficient analysis. Finally, a 10kV distribution network is used in case study to validate the proposed method. The results for a time-consuming calculation, that is, TSC curve calculation, show that the proposed method can reduce the computation time significantly, making the time-consuming calculation suitable for the analysis of large-scale cases.