Characterization of electrical incipient fault signature resulting from tree contact with electric distribution feeders

As budgets have decreased for regular trimming of trees on utility distribution systems in the US, the systems have become more likely to experience contact of branches of trees with distribution conductors. Detection of this phenomenon could provide vital predictive maintenance information. This paper discusses research efforts to characterize the tree contact phenomenon through field experiments, visual observations, and computer data analysis. A single-phase lateral is attached to a pole from which three phase lines have been tapped off an overhead distribution system. Tests were staged by bringing tree limbs and branches of trees in their natural setting into contact with a live phase conductor of the medium voltage overhead line and then energizing the lateral. Various types and sizes of tree branches and limbs were used in the tests. Visual observations made before, during and after the tests and the analytical properties of this behavior are discussed.