The authors regret that the published manuscript [1] contains typographic error in labelling a reactance value for a particular line in both Figs. 1 and 2 of the original manuscript. In both of these cases, the reactance of the line A β C should be labelled as 0.1 pu. The other lines in these diagrams should be annotated with reactances of 1 pu but the central line A β C should be 0.1 pu.