Rapporteure's report: Session D Treeing in polyethylene

This group of papers report on much of the recent investigations of electrochemical or water treeing breakdown in polyethylene and polyethylene cables. Nine of the ten papers deal with electrochemical treeing and one (page 207∗) considers primarily electrical treeing in dry conditions. A number of cable failures in service have been associated with the evidence of numerous partial breakdowns in the cable having the appearance of a small tree or bush. This is the reason for the intensive study of this phenomena, particularly in Japan and North America.