ABSTRACT
The power transmission line is one of the main components of an electric power system. Its major function is to transport electric energy, with minimal losses, from the power sources to the load centers, usually separated by long distances. The design of a transmission line depends on four electrical parameters: series resistance, series inductance, shunt capacitance and shunt conductance. Alternating current (AC) resistance of a conductor in a transmission line is based on the calculation of its direct current resistance. Frequency of AC voltages produces a second effect on the conductor resistance due to the non-uniform distribution of the current. There are two types of transmission line conductors: overhead and underground. In actual transmission lines, the resistivity of the conductors produces a small internal electric field, and therefore, the electric field at the conductor surface is smaller than the estimated. Once evaluated, the line parameters are used to model the transmission line and to perform design calculations.
