Arc Resistance and Application of FRP to Arms in Overhead Power-Line Towers

Concerning the application of insulation arms to overhead transmission structures, some tests on the arc-resistance nature of insulating materials have been performed mainly by means of a plasma jet generator. Several materials were exposed to the plasma flame and the state of the surface degeneration was examined. From the results, the relation between arc resistivity and the chemical structure of materials has been clarified to some extent. This fundamental information yields some excellent fiber glass reinforced plastics (FRP) under actual arc discharge. The insulation arms made of improved FRP have been used successfully on actual overhead line towers as a tension crossarm member to compensate for the lack of clearance.