Influence of Centrality Indexes on the Transmission Expansion Planning Problem

Electric transmission systems can be represented as complex networks; therefore, they can be characterized topologically by their connections between nodes and directions so that centrality indexes can differentiate nodes of greater or lesser importance. More meshed networks can better supply the load increase than lesser ones; therefore, identifying key network nodes would help to decide where grid additions are important from the topological point of view. This research analyses the influence of PageRank, eigenvector, betweenness, authorities, and hubs centralities on the transmission network expansion problem (TNEP) for the 6-bus Garver and 24-bus IEEE systems. The results concluded that the coefficient of variation of these indexes is lower for an optimal system than for infeasible or high-cost topologies. In addition, some indexes calculated for the base case (before the expansion) indicated most of the same nodes (or branches) as those obtained in the optimal network, where grid reinforcements are necessary.