General Methodology for Asymmetrical Fault Analysis in Linear and Symmetrical Multi-phase Power Systems

In this work, a general method to analyze any type of fault in a multi-phase power system is introduced. The proposed methodology is based on the superposition principle and on the decoupling produced by the transformation of symmetrical components into symmetrical and cyclic multi-phase systems. Different connections of positive, negative, and zero sequence networks are used in the traditional fault analysis using symmetrical components. In this paper, the possibility of analyzing faults using a procedure that consists of determining n boundary conditions in the phase domain, converting these to the frequency domain, and incorporating n additional conditions by means of the decoupled sequence networks, is proposed. The result is a system with 2n equations and 2n unknowns in sequence, which can finally be transformed into the phase domain. To validate the methodology, several asymmetrical faults (line-to-line short circuits, line-to-ground, etc.) in power systems are performed, the sequence networks are determined by means of the ATP-EMTP program, and the results are obtained using this program and the proposed technique are compared.