Influence of fatigue on some electrical ageing mechanisms of polymers

The role of fatigue in the electrical endurance of crosslinked polyethylene and polypropylene and in water treeing in crosslinked polyethylene is discussed. Analysis of existing experimental results shows that the number of AC field cycles is a much better normalising parameter of electrical aging than time. It also suggests that the water-tree length and density increase logarithmically with the number of cycles, apparently independently of the test frequency.