1 Introduction

Transmission and distribution lines consist of an arbitrary spatial arrangement of one or more conductors. Information about these conductors is transformed into parameters required for power system analysis as follows:

  • The fundamental data consists of a description of each conductor and how the conductors are arranged on their support structures.

  • Conductor and spacing information is converted into an impedance matrix representing the self and mutual impedances of the complete configuration.

  • The impedance matrix is reduced to eliminate elements that are not required by the analysis.

  • The reduced impedance matrix is converted to symmetrical components when sequence impedances are required.

If sequence impedances are the only available information, they can be transformed into a reduced impedance matrix.

The remainder of this document examines the first two stages of this modeling process in detail. That is, we examine techniques for transforming conductor parameters and configuration data into impedance and capacitance matrices. The analysis is limited to overhead transmission lines.