Title :
Propagation mechanism of electrical tree in XLPE cable insulation by investigating a double electrical tree structure
Author :
Zheng, Xiaoquan ; Chen, George
Author_Institution :
State Key Lab. of Power Equip. & Electr. Insulation, Xi´´an Jiaotong Univ., Xi´´an
fDate :
6/1/2008 12:00:00 AM
Abstract :
This paper presents our experiments and analysis of the electrical tree growing characteristics. The relationship between electrical tree propagation and the material morphology in XLPE cable insulation has been studied by researching the structure and growth characteristics of a double structure electrical tree. It has been found that, due to the influence of uneven congregating state, difference in crystalline structure, and the existence of residual stress in semi-crystalline polymer, five types of electrical tree structures (branch, bush, bine-branch, pine-branch, and mixed configurations) would propagate in XLPE cable insulation. Three basic treeing propagation phases (initiation, stagnation, and rapid propagating phases) are presented in electrical tree propagating process. If initiation phase is very active, the single branch tree will propagate while if this phase is weak then the bush tree will occur more easily. There would be a clear double structure of electrical tree when it grows at submicroscopic structure uneven region of the material. A new parameter, the expansion coefficient is introduced to describe the electrical tree propagation characteristics. In addition, two other coefficients being used to describe our experimental results are dynamic fractal dimension and growth rate of electrical tree.
Keywords :
XLPE insulation; power cable insulation; trees (electrical); XLPE cable insulation; bush tree; crystalline structure; double electrical tree structure; dynamic fractal dimension; electrical tree growing characteristics; electrical tree propagating process; electrical tree propagation; expansion coefficient; initiation phase; material morphology; phase mechanism; residual stress; semi-crystalline polymer; treeing propagation phase; uneven congregating state; Cable insulation; Crystalline materials; Dielectric materials; Dielectrics and electrical insulation; Morphology; Plastic insulation; Polymers; Tree data structures; Trees - insulation; Voltage;
Journal_Title :
Dielectrics and Electrical Insulation, IEEE Transactions on
DOI :
10.1109/TDEI.2008.4543118