Topological characteristics and algorithm of N-1 security boundary for smart distribution network

To make a research on topological characteristics of N-1 security boundary for smart distribution networks, the approach and fitting algorithm of security boundary based on N-1 simulation is proposed. First, total supply capability (TSC) was calculated. Then, from the TSC point, a series of critical points on the boundaries were searched by N-1 security simulation and approximating approach. Finally, 2-dimension cross section figure was obtained in feeder load space by least squares method. With the algorithm above and according to the simulation and observation from case studies, topological characteristics of security boundary are derived, besides, its formation cause and application significance are elaborated. Based on analysis of massive 2-dimensional sections, it is proved that distribution N-1 security boundary exists deterministically and uniquely, and it can be described precisely as a liner, compact and non-knotting hyperspace. The space surrounded by the boundaries is a connective convex set without empty inside. The conclusions indicate that these characteristics above are suitable for developing fast region-based security evaluation method; and make it easy for online security evaluation and control of distribution networks. © 2014 Chin. Soc. for Elec. Eng.