General fault analysis using phase frame of reference

Traditionally, the analysis of power systems under unbalanced fault conditions is carried out using symmetricalcomponent theory. In the paper, an alternative approach, using phase frame of reference, is presented. Full network representation is used, which allows for network asymmetry arising from unbalanced generator impedances or nontransposition of transmission lines. Any type of fault can be represented singly or in combination. Sparsity methods are used to reduce the computation time and storage to a minimum. A special method is incorporated for quadrature-boosting transformers that provides direct solution and retains symmetry of the network equations