Sparsity-enhanced network reduction for fault studies

A new short-circuit equivalent and reduction program is described that uses the adaptive reduction technique in which extra path nodes are retained to produce a sparser equivalent network. Nodes that may be reduced are chosen by flexible set formation facilities, with path nodes automatically retained as required to preserve sparsity. Tests on typical systems show that the sparsity-enhanced reduction produces an equivalent with fewer branches and a much lower branch-to-node ratio than conventional reduction for a wide range of numbers of nodes eliminated. At some point, as the number of retained nodes becomes small, conventional reduction produces an equivalent with fewer branches