Abstract
This paper analyzes the distribution of the corona discharge current distribution and the ambient electric field intensity on an EHV transmission tower during a thunderstorm. In the measurement of corona discharge current from the arm ends of a tower at Mt. Okushishiku in 1996 and again in 1998, unexpected phenomena were observed in the corona current and the charge distribution. The different polarities of the corona discharge current were intermittently measured at the different arm ends of a transmission tower. Through these measurements, the initiation field intensity of the corona discharge current and the field intensity on the top of the tower were observed for the first time.
