Analysis on Secondary Growth Characteristics of Electrical Trees in XLPE Cable

In order to study the growth characteristics of electrical trees in XLPE cable under secondary pressuring, a short cable metal needle defect test device is adopted to study the growth characteristics of the new trees after the electrical trees in XLPE cable under the action of the voltage of 12 kV are influenced by secondary pressuring (15 kV). The research results show that influenced by secondary pressuring and voltage increase rate, there will be a peculiar ldquobush-branchrdquo electrical tree in XLPE cable insulation layer and the new trees under secondary pressuring have the characteristics of short initiation time, fast growth rate and narrow discharge channel, etc, which shows that secondary pressuring has a great effect on the secondary initiation and growth of electrical trees in XLPE cable and it is an important factor of accelerating cable aging and breakdown.