A new methodology for determining transmission capacity margin in electric power systems

The authors define transmission capacity margin, illustrate how the built-in margin method can cause simulation inaccuracy and how this inaccuracy can lead to erroneous analysis, and describe a new approach to implementing margin, referred to as the interpreted margin method, whereby simulation results are interpreted according to a margin criterion. This method requires accurate simulation models, intelligent quantification of margin, and a methodology for determining sufficiency of margin. In addition, terminology is developed that can be used to pursue further discussion of this topic. Although the focus is on margin as it is affected by operating studies, the ideas could also be applied to margin as it is affected by planning studies, recognizing that more uncertainty is associated with planning studies due to the longer time interval between study completion and implementation of recommendations