DC Tree Associated with Space Charge in PMMA

Journal of International Council on Electrical Engineering

2018

Grounded DC tree is a serious threat for the safe operation of XLPE cable. In this paper, growth properties of grounded DC electrical trees in XLPE under ±40kV DC voltage were investigated and analyzed. The results showed that DC voltage polarity had a remarkable impact on the growth characteristics of grounded electrical tree. Sparse-branch and dense-branch electrical trees were more likely to form under positive and negative voltage, respectively. Meanwhile, the time of typical grounded DC tree samples growing to 1mm was also calculated. The results indicated that the average growing time under positive voltage could be a bit shorter than that under negative voltage. The results in this paper can help in the understanding of DC tree mechanism and provide a support for the later experiments.

Section: Introductionmentioning

confidence: 98%

Research of grounded DC electrical tree growth properties in XLPE

Zhang

Journal of International Council on Electrical Engineering

2018

“…As described previously, the research on dc-tree is inadequate. It had been reported that I. Kitani with his work team studied the effect of space charge on the dctree initiation properties in PMMA [5], and Yasuo Sekii's team found the relationship between antioxidant and space charge with the initiation voltage of XLPE insulator [6]. In addition, the effect of DC voltage polarities on tree initiation and propagation is also significant.…”

Section: Introductionmentioning

confidence: 98%

Research of grounded DC electrical tree growth properties in XLPE

Zhang

Journal of International Council on Electrical Engineering

2018

Grounded DC tree is a serious threat for the safe operation of XLPE cable. In this paper, growth properties of grounded DC electrical trees in XLPE under ±40 kV DC voltage were investigated and analyzed. The results showed that DC voltage polarity had a remarkable impact on the growth characteristics of grounded electrical tree. Sparse-branch and dense-branch electrical trees were more likely to form under positive and negative voltage, respectively. Meanwhile, the time of typical grounded DC tree samples growing to 1mm was also calculated. The results indicated that the average growing time under positive voltage could be a bit shorter than that under negative voltage. The results in this paper can help in the understanding of DC tree mechanism and provide a support for the later experiments.

“…When the local electric field intensity is too high, the insulation will deteriorate or even break down, forming a dendritic discharge channel. The continuous development of an electrical tree can be considered as the process of space charge penetrating into the dielectric along the tip of the tree [3]- [5]. The influence mechanism of space charge on an electrical tree is complicated.…”

Section: Introductionmentioning

confidence: 99%

Simulation of Influence of DC Pre-Stress on Space-Charge Characteristics of Cross-Linked Polyethylene in Inhomogeneous Field

Liu³

et al. 2020

IEEE Access

Space charge is one of the main causes of electrical tree initiation in high-voltage cable insulation. To investigate the influence of DC pre-stress on the space-charge distribution of cross-linked polyethylene (XLPE), a two-dimensional needle-plate electrode model is established in this study. Based on the bipolar charge-transport model, the space-charge distribution characteristics of the needle-plate electrode model under DC pre-stress are simulated and analyzed. The space-charge distribution characteristics are compared with that of the grounded DC electrical tree initiation properties. The work in this study illustrates that the pre-stress time and value affect the space-charge distribution characteristics. There is a certain relationship between space-charge distribution characteristics and electrical tree initiation characteristics. The distribution range of the DC grounded electrical tree is very similar to that of space charge. Both have a similar distribution shape and increased trend under different pre-stress times, and both have an obvious polarity effect. INDEX TERMS DC pre-stress, Grounded electrical tree, Space charge simulation, XLPE.