Extension of the canonical model to grounding parts of power systems under fault conditions

Abstract

This paper deals with calculations of alternate components of states of power systems in arbitrarily chosen composite fault conditions. Canonical model is applied for these calculations. This model was already established for calculations of states of energized parts of faulted power systems. It is applied in this paper for calculations of the states of grounded parts as well. Thus, the model refers to arbitrarily small or large portions belonging to only one or both energized and grounded parts of power systems. By the canonical model application, standard procedures established for calculations of states in energized parts are extended for calculations of states of grounded parts of faulted power systems. This extension is provided by three basic generalizations: (1) the standard three-dimensional three-phase quantities are generalized as four-dimensional ones; (2) the standard three-dimensional symmetrical components transformation is generalized as four-dimensional one; (3) the application of the standard p.u. method is substituted by the generalized p.u. method. The model is verified in details by an example referring to a line to ground short-circuit occurred on an overhead line. It is also stated for solution of a composite fault which consists of the above mentioned fault associated with a line interruption. © 2003 Elsevier Science Ltd. All rights reserved.