ABSTRACT
The modeling of distribution overhead and underground line segments is a critical step in the analysis of a distribution feeder. It is important in the line modeling to include the actual phasing of the line and the correct spacing between conductors. This chapter develops the "exact", "modified", and "approximate" line segment models. The exact model uses no approximations. That is, the phase impedance matrix, assuming no transposition, and the shunt admittance matrix are used. The modified model ignores the shunt admittance. The approximate line model ignores the shunt admittance and assumes that the positive and zero sequence impedances of the line are the known parameters. This is paramount to assuming the line is transposed. For the three line models, generalized matrix equations have been developed. The modified model ignores the shunt admittance. The approximate line model ignores the shunt admittance and assumes that the positive and zero sequence impedances of the line are the known parameters.
