Investigation on lightning attachment manner by use of an experimental distribution line and a tree

The authors have examined over a period the basic characteristics of discharge when an open wire fitted as an overhead ground wire is located near a tree, to clarify the attachment manner in which direct lightning hits power distribution lines which are in close proximity to trees. Previously, a focus was made on how lightning attachment emerges to the open wire or the tree. In this latest experiment, made at a testing yard using an experimental distribution line and a tall tree, a lightning impulse waveform and a switching impulse waveform were applied individually to a rod electrode. The different manners of attachment of sparkover to the distribution line and the tree were observed, along with manners of prebreakdown phenomena. This result coincided with the lightning attachment status previously achieved. This experiment revealed that the discharge characteristics shown in the previous study are valid.