ABSTRACT
This chapter discusses many of the key electrical considerations of overhead lines: conductor characteristics, impedances, ampacity, and other issues. Overhead constructions come in a variety of configurations. Overhead lines have resistance and reactance that impedes the flow of current. These impedance values are necessary for voltage drop, power flow, short circuit, and lineloss calculations. In rural areas, utilities can use smaller conductors and longer pole spans, so Aluminum Conductor, Steel Reinforced or another of the higher-strength conductors is more appropriate. Copper has very low resistivity and is widely used as a power conductor, although its use as an overhead conductor has become rare because copper is heavier and more expensive than aluminum. The ampacity is the maximum designed current of a conductor. A copperweld conductor has copper-coated steel strands, and an alumoweld conductor has aluminum-coated steel strands. Because the neutral conductor carries lesser current than the phase conductors, utilities can use smaller neutral conductors.
