Identifying the retained portion of an equivalent network using distribution factor sorting

Abstract

Distribution factor using sorting methodology is applicable to a number of network oriented problems, although its primary use is intended for electric utility system planning studies and for off-line studies in control centers. This paper presents a discussion of the development testing of an analytical method of sorting distribution factors to identify the portion of a network model that should be retained in a reduced equivalent. The method uses line outage distribution factors (LODFs) to represent network sensitivities in this identification process. The LODFs are attainable directly from the network impedance data, thus reducing processing time. Two computer programs accomplish the data manipulation and calculations necessary in the analytical method. Furthermore, the method is consistent and does not depend on prior knowledge of the way the system reacts to various changes. Application of distribution factor sorting to a test model shows that it provides excellent results. Reduced network models which result from application of the method faithfully represent the unreduced model. Network analysis using the resulting reduced model is enhanced by the retention of elements in the external system which have significant impact (when outaged) on the study area.