An Approach for Impedance Matrix Computation Considering Phase Transposition on Distribution Lines

Abstract

A renewed interest in phase frame analysis of distribution systems has surfaced in recent literature due to rapid expansion of grid-integrated distributed generation and non-linear loads, whose grid imbalance-increasing effects require more detailed analysis and modeling of distribution systems for their proper assessment. In this paper, under motivation of such recent usage of phase frame components, we propose analytical equations for N-phase neutral-equipped line admittance matrix under transposition assumption. By using the proposed equations, we evaluate precision losses caused by using the transposition assumption for modeling three-phase four-wire distribution lines. Moreover, differently from previous works, we validate the transposition assumption and the admittance matrix values obtained for various combinations of cable type and line geometry. A relevant reason for analyzing transposition assumption in more detail is the fact that it may be useful in distribution system computations, due to its advantageous decoupling of symmetrical components. In this sense, the present work provides additional discussion and illustrative evaluations of the line transposition assumption, which may be useful for analyzing its applicability under different circumstances.