Dimension of distribution system security region: concept, calculation and application

Abstract

This study proposes the concept, calculation and application of dimension of distribution system security region (DSSR). Two forms of DSSR dimension are presented: one is named binary dimension; the other is called unary dimension. First, the binary dimension is defined as the number of security boundaries and the number of variables in them. A method based on main transformers connection vector can obtain binary dimension without listing model expressions of DSSR. Second, the unary dimension is proposed, which uses a single value in the form of Ne × Ne to describe the scale. This form is convenient to compare the scale of different DSSRs. Moreover, a method based on association matrix is also presented. Third, a case is used to illustrate proposed definitions and methods. The relationship between distribution network and its DSSR dimension is analysed separately. Finally, the application of DSSR dimension is discussed. The unary dimension is applied to solve the problem of large-scale combinations for two-dimensional observation on DSSR. Any two feeders are possible to be combined, but many combinations are unnecessary. By the proposed method, the combinations that are really needed can be accurately obtained, and the use of DSSR is simplified.