TERMINAL-TERMINAL PETIR UDARA DAN METODE PERANCANGAN DAN PENGGUNAANNNYA

摘要

Air terminals of two types having curved surface electrodes that act passively or dynamically to minimize or further reduce corona during the close approach of the down leader. In the first type, a fully grounded passive terminal, suitably located and comprising a conductive curved surface of a given radius on a grounded rod of given height, is located and suitably dimensioned in order to minimize corona discharges until the median field rises to a level sufficient to support streamer to leader conversion, as described below. In the second type, dynamic action is achieved by allowing the curved surface to float upwardly in voltage by use of capacitive coupling to the approaching leader. The raising of voltage being in the same polarity as the leader, acts to reduce the electric field immediately above, with consequent reduction in corona. When a flashover point is reached between the curved surface and the main earthed electrode there are provided free electrons in avalanche mode, and the curved surface is simultaneously grounded through the arc. This grounding causes an instant increase in the electric field immediately above the terminal. Streamer formation is enhanced by the liberation of free electrons, the photoionization created by the arc, and the instant increase in the electric field strength ahead of the streamer.