Strict and Non-Strict Security Boundary of Distribution Network

This paper proposes the definition and calculation methods for strict and non-strict security boundary of distribution network. Firstly, according to the criticality degree of the security boundary point, the strict and non-strict boundary are defined respectively. Strict boundary has the property of strict criticality, while non-strict boundary has the property of non-strict criticality, which together constitute a complete security boundary. Secondly, by analyzing the causes of strict boundaries, this paper divided them into two types: intersection type and independence type. Generally, strict boundaries of most distribution networks are intersection boundaries that are formed by intersection of multiple hyperplanes. Only in some special cases with an extremely small scale, the independence strict boundary can be formed when all loads are limited by the same constraint after N-1. Thirdly, the boundary type judgment theorem and inferences based on the determination matrix are presented. Then, an algorithm is presented for solving the strict and non-strict boundaries. That is, all the intersection boundaries are judged by using the determination matrix firstly, and the complete strict boundary is obtained, and then the complement of the strict boundary is solved to obtain the complete non-strict boundary. Finally, case study verifies the proposed method. Moreover, strict and non-strict boundaries in the cases are shown by visualization. © 2019, Electrical Technology Press Co. Ltd. All right reserved.