Laser-Guided Discharge Characteristics of Long Air Gaps and Observation of the Discharge Process.

Laser-guided discharge is promising for protection of power transmission systems against lightning. Several experiments concerning the laser-induced electrical discharge have been performed up to now. However, it is necessary to understand the mechanism of the laser- induced electrical discharge to achieve the laser-triggered lightning. When a high-power laser beam is focused in air, a high degree of ionization is produced as brilliant beams near the focus. In this paper. the electrical discharge induced up to 2-meters with a high-power CO² laser focused by a 10-meter focal length mirror is described. Experiments of the laser-guided discharge were carried out by application of an impulse voltage to a rod- rod gap after laser radiation. This paper deals with the effects of delay times and polarity of the impulse voltage on 50 percent flashover voltage characteristics and the observation results of discharge phenomena taken by a still camera, a special camera named ALPS (Automatic Lightning Discharge Progressing Feature Observation System) and an image converter camera. [ABSTRACT FROM AUTHOR]