Corona-Loss Characteristics of EHV Transmission Lines Based on Project EHV Research

Since 1960 the corona-loss characteristics of a variety of extra-high-voltage (EHV) transmission-line configurations have been under study at Project EHV [1], [2]. This paper presents results from the analysis of corona losses measured under all weather conditions experienced during 2½ years of observation of single or bundled conductors at 500 or 700 kV. In addition, corona characteristics are presented for switching-surge transients and severe steady-state overvoltages. The purpose of this paper is: 1) to summarize some of the statistical aspects of fair-and foul-weather corona-loss observations for the configurations studied, and 2) in terms of electrical and meteorological parameters, to describe an equation for corona loss on EHV lines that is in a form directly applicable by transmission engineers to EHV-line design.