scholarly journals Effect of Air Gap on Electrical Tree in Epoxy Resin Under High Frequency Bipolar Square-Wave Voltage

Materials ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 5722
Author(s):  
Shihang Wang ◽  
Chuang Zhang ◽  
Hang Fu ◽  
Jiao Xiang ◽  
Jianying Li ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
High Frequency ◽  
Air Gap ◽  
Heat Accumulation ◽  
Air Gaps ◽  
Square Wave ◽  
Electrical Tree ◽  
Electrical Trees ◽  
Voltage Frequency ◽  
Tree Characteristics

Insulation fails quickly under high-frequency AC high voltage, especially bipolar square-wave voltage with a high dV/dt. It is of great significance to study the failure mechanism of epoxy casting insulation under such kind of voltage. In this paper, pin-plane epoxy casting insulation samples with air gaps were prepared, and the relation between the electrical trees under the high frequency bipolar square-wave voltage and the air gap conditions and voltage frequencies (1~20 kHz) were studied. Results indicated that, with the presence of air gaps, the electrical trees were bush-type and had a relatively slow growth rate, which was different from the fast-growing branch-type trees in the samples without air gap. The electrical tree characteristics related with the size of air gap and voltage frequency were also studied. The electrical tree grew faster under higher voltage frequency or with a smaller air gap. Results proved that discharge introduced a lot of defects for the surface layer of the epoxy resin samples and hence induced the possibility of multi-directional expansion of electrical trees. In addition, the resulting heat accumulation and unique charge transport synergistically affected the electrical tree characteristics under the high frequency bipolar square-wave voltage.

scholarly journals Influence of Repetitive Square Voltage Duty Cycle on the Electrical Tree Characteristics of Epoxy Resin

Polymers ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2215 ◽  
Author(s):  
Peng Wang ◽  
Suxin Hui ◽  
Shakeel Akram ◽  
Kai Zhou ◽  
Muhammad Tariq Nazir ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Duty Cycle ◽  
Electronic Device ◽  
Wide Band ◽  
Shielding Effect ◽  
Power Electronic ◽  
Square Wave ◽  
Electrical Tree ◽  
Duty Cycles ◽  
Electrical Trees

The application of wide band-gap power electronic devices brings more challenges to insulating packaging technology. Knowing the influence of applied voltage parameters on insulation performance is helpful to evaluate the insulation condition of electric power equipment. In this paper, the effect of repetitive square wave voltage duty cycle on the growth characteristics of electrical trees in epoxy resin was studied. The experimental results show that the square wave voltage duty cycle has a significant influence on treeing features. The electrical tree proportion initiation has shown a decreasing trend, and the shape of the electrical tree changes from pine-like to branch-like by increasing the duty cycles. The length and damaged area of electrical tree increased with the increase in the duty cycle up to 10% and then decrease by increasing the duty cycle higher than 30%. It indicates that a low duty cycle will enhance the electron injection and accumulate space charges and thus accelerate electrical tree development. Under short duty cycles, the electric field due to the shielding effect near the needle tip suppresses the electrical tree growth, which results in treeing growth stagnation. The obtained results are helpful to keep these parameters in mind during the design of epoxy-based insulation such high-voltage rotating machines and power electronic device packaging.

Electrical Tree Characteristics of Epoxy Resin under Bipolar Square Wave Voltage

2020 ◽  
Author(s):  
Hang Fu ◽  
Chuang Zhang ◽  
Jiao Xiang ◽  
Zhuolin Cheng ◽  
Shihang Wang ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Square Wave ◽  
Electrical Tree ◽  
Tree Characteristics

scholarly journals Effects of bipolar repetitive square wave voltage parameters on electrical tree characteristics of epoxy resin

2021 ◽  
Vol 103 ◽  
pp. 107371
Author(s):  
Peng Wang ◽  
Yiwen Chen ◽  
Shakeel Akram ◽  
Pengfei Meng ◽  
Jerome Castellon ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Square Wave ◽  
Electrical Tree ◽  
Tree Characteristics

scholarly journals Application of the Gaussian Mixture Model to Classify Stages of Electrical Tree Growth in Epoxy Resin

Sensors ◽  
2021 ◽  
Vol 21 (7) ◽  
pp. 2562
Author(s):  
Abdullahi Abubakar Mas’ud ◽  
Arunachalam Sundaram ◽  
Jorge Alfredo Ardila-Rey ◽  
Roger Schurch ◽  
Firdaus Muhammad-Sukki ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Gaussian Mixture Model ◽  
Mixture Model ◽  
Tree Growth ◽  
Asset Management ◽  
Gaussian Mixture ◽  
Growth Stages ◽  
Insulation Material ◽  
Electrical Tree ◽  
Electrical Trees

In high-voltage (HV) insulation, electrical trees are an important degradation phenomenon strongly linked to partial discharge (PD) activity. Their initiation and development have attracted the attention of the research community and better understanding and characterization of the phenomenon are needed. They are very damaging and develop through the insulation material forming a discharge conduction path. Therefore, it is important to adequately measure and characterize tree growth before it can lead to complete failure of the system. In this paper, the Gaussian mixture model (GMM) has been applied to cluster and classify the different growth stages of electrical trees in epoxy resin insulation. First, tree growth experiments were conducted, and PD data captured from the initial to breakdown stage of the tree growth in epoxy resin insulation. Second, the GMM was applied to categorize the different electrical tree stages into clusters. The results show that PD dynamics vary with different stress voltages and tree growth stages. The electrical tree patterns with shorter breakdown times had identical clusters throughout the degradation stages. The breakdown time can be a key factor in determining the degradation levels of PD patterns emanating from trees in epoxy resin. This is important in order to determine the severity of electrical treeing degradation, and, therefore, to perform efficient asset management. The novelty of the work presented in this paper is that for the first time the GMM has been applied for electrical tree growth classification and the optimal values for the hyperparameters, i.e., the number of clusters and the appropriate covariance structure, have been determined for the different electrical tree clusters.

Electrical tree characteristics of epoxy resin under AC voltage at 77 K

Cryogenics ◽  
2019 ◽  
Vol 99 ◽  
pp. 123-129 ◽  
Author(s):  
Yongguang Wang ◽  
Rongjin Huang ◽  
Chuanyang Li ◽  
Chi Zhang ◽  
Fuzhi Shen ◽  
...  
Keyword(s):  
Epoxy Resin ◽  
Electrical Tree ◽  
Tree Characteristics

scholarly journals Electrical Trees in a Composite Insulating System Consisted of Epoxy Resin and Mica: The Case of Multiple Mica Sheets For Machine Insulation

2014 ◽  
Vol 4 (4) ◽  
pp. 662-668 ◽  
Author(s):  
V. A. Kioussis ◽  
M. Danikas ◽  
D. D. Christantoni ◽  
G. E. Vardakis ◽  
Α. Bairaktari
Keyword(s):  
Cellular Automata ◽  
Epoxy Resin ◽  
Partial Discharges ◽  
Experimental Results ◽  
Rotating Machine ◽  
Electrical Tree ◽  
Electrical Trees ◽  
Simulation Results

Epoxy resin and mica sheets consist the essential insulation of rotating machine stator bars. Such an insulation, although very resistant to partial discharges, is subjected to considerable electrical stresses and consequently electrical trees may ensue. In this paper, an effort is  made to simulate electrical tree propagation in multiple epoxy resin/mica sheets with the aid of Cellular Automata (CA). An attempt to compare the simulation results with experimental results is also made.

Sign in / Sign up

Export Citation Format

Share Document