抄録
The possibility whether measurement of residual charge is usable as a tool to detect water trees in crosslinked polyethylene is discussed. The results obtained are summarized as follows. (1) Residual charge was not measured in a sheet sample because of its small electrode area. (2) Residual charge was detected in a cable sample. (3) A clear frequency dependence of the residual charge was not observed. A model of the residual charge measurement is proposed, where the charges accumulated in a water tree are oscillated by ac electric field and are diffused through the water tree path with a high conductivity.
