A generalized computer technique for the development of the three-phase impedance matrix for unbalanced power systems

Abstract This paper presents the development of the three-phase bus impedance and bus admittance matrices for unbalanced power systems. The imbalance conditioned by large single-phase loads, untransposed feeders, bundled conductors, etc., is reflected in the polyphase impedance or admittance matrix. The method utilizes the phase frame representation of network elements. Consequently, line removals or additions, impedance changes, conductor and phase openings can be simulated easily by modifying the bus impedance matrix. Thus, the proposed method makes it possible to analyze any type of single- or three-phase loads and unequal mutual coupling between the phases for large-scale power systems.