Applying exact MILP formulation for controlled islanding of power systems

In this paper an exact ICI algorithm based on a MILP formulation that directly determines an islanding solution with minimal power-flow disruption for any given number of islands is proposed. The constraints applied when satisfying this objective function deal with coherent generator groups and transmission line availability. Additionally, the algorithm allows the control of the size of islands and ensures the connectivity inside them. Since the MILP formulation allows the easy manipulation of its existing constraints, a preprocessing procedure is also developed for reducing the search space of the MILP. The objective of the preprocessing procedure is to find a tree for each island with minimum number of nodes, spanning to all generator nodes of its coherent group. The nodes that are included in these trees are directly assigned to their resulting island, ensuring the generator coherency. The effectiveness and the computational efficiency of the proposed ICI algorithm have been demonstrated under different system conditions.