Corona Activity on Single-circuit Overhead Transmission Lines under Variable Altitude

Corona performance of overhead transmission lines is affected, in addition to line geometry and voltage, by the surface state of the line conductors as well as by the atmospheric, weather and pollution conditions prevailing along the route of the line. As a result, analytically assessing corona activity on conductors under practical operating conditions is a difficult task. However, it is important since the corona onset field of line conductors is a crucial input in evaluating the electric field and ion current environment near the line as well as the associated corona effects, namely power loss, radio interference and audible noise. In this study corona activity on single-circuit overhead transmission lines is evaluated under the influence of altitude, considering atmospheric conditions and the conductor surface state. A simple empirical expression is proposed for altitude correction of the corona inception voltage.