| 摘要 |
<p>An improved lightning conductor (1) is provided which has an earthed conductor element (11) surrounded by a rounded conductive surface element (12), a high impedance bleed circuit (17) connected between the conductive surface element (12) and earth, and a triggering electrode (14) positioned adjacent or above the upper end of the conductor element (11) and connected electrically to the conductive surface element (12). The conductor element (11) is preferably a tube with the triggering electrode (14) disposed on the central axis of the tube. An insulating spacer (15) is provided between the tube (11) and the triggering electrode (14). In use, the rounded surface element (12) minimises the produciton of corona and the high impedance bleed circuit (17) delays the production of a triggering arc between the triggering electrode (14) and the earthed conductor (12) until the rapid approach of a lightning down leader. The triggering arc, which occurs at the highest point of the lightning conductor (10), causes a stepped increase in the near electric field above the conductor (10) to provide ideal conditions for upleader initiation and propagation.</p> |
