The Impedance Chart and its Application in Obtaining the Shape and Complex Plane Position of the Out-Of-Step Polygons

A simple graphical method (P. Kundur, 1993) could be used to obtain the appropriate shape and the correct complex plane location of the OOS polygons at locations where the swing traces a classical locus. The swing locus could, however, be greatly non-classical at certain locations in networks that have shunts (i.e. loads, voltage regulating shunts, etc) [1]. At locations where the swing locus is greatly non-classical the appropriate shape and the correct complex plane location of the OOS polygons should be obtained using the impedance chart.