Investigation of electrical treeing in perspex material

Perspex has been known for a long time as a polymeric material, and it has been used for a large number of electrical and non-electrical applications. The present work was carried out to investigates the ageing mechanism of perspex material under a high electric field. The electrical treeing phenomenon was studied using perspex samples with electrodes of a pin-to-plane configuration. The growth of an electrical tree in Perspex was measured and analysed with the aid of an advanced microscope, equipped with a high-resolution camera and connected to a personal computer. Several distinct stages were assigned to characterise the electrical tree development. The area occupied by the electrical tree channels was calculated using equal-area squares. This approach was employed to measure the growth rate of electrical trees under dry and wet conditions. The tree construction, shape and growth speed were studied and analysed to distinguish between treeing phenomenon under wet and dry conditions of fabricated perspex specimens. The absorption of water has increased the tree growth inside the samples, and ions with water have accelerated the breakdown process. The findings of this study are essential to improve the performance of perspex material, which is widely used in a variety of applications for both energy and non-energy purposes.

Download Full-text

Study on the Relationship between Electrical Tree Development and Partial Discharge of XLPE Cables

Journal of Nanomaterials ◽

10.1155/2019/8932312 ◽

2019 ◽

Vol 2019 ◽

pp. 1-10 ◽

Cited By ~ 2

Author(s):

Chaofei Gao ◽

Yanlong Yu ◽

Zan Wang ◽

Wei Wang ◽

Liwei Zheng ◽

...

Keyword(s):

Statistical Characteristics ◽

Time Frequency ◽

Experimental Platform ◽

Equivalent Time ◽

Electrical Tree ◽

Electrical Trees ◽

Insulation Breakdown ◽

The Relationship ◽

Frequency Diagram ◽

Tree Development

Based on the slice materials of 35 kV and 110 kV XLPE cables, an experimental platform is built to study the relationship between electrical tree and PDs in XLPE with different voltage levels. There are three significant statistical characteristics of the PDs during the growth of electrical trees. The analysis of the results shows that each growth stage has certain characteristics. Different features existed between the growth of the electrical trees and the PD in the insulation of the 35 and 110 kV cables. Evident characteristics such as large spans of time and frequency were present as the electrical trees grew violently in the equivalent time-frequency diagram at every stage. These results could provide criteria for the identification of the deterioration using PD to monitor cables in service at rated voltages. The results are important for the identification of defects in cable insulation in order to provide an early warning of insulation breakdown in the cables.

Download Full-text

Fractal Characteristic of Electrical Trees Grown in Silicone Rubber under Environmental Stress

International Journal of Electrical and Computer Engineering (IJECE) ◽

10.11591/ijece.v7i3.pp1628-1632 ◽

2017 ◽

Vol 7 (3) ◽

pp. 1628

Author(s):

M. S. Mohd Fua’ad ◽

M.H. Ahmad ◽

Y. Z. Arief ◽

N. A. Ahmad

Keyword(s):

Fractal Dimension ◽

Fractal Structure ◽

The Self ◽

Fractal Structures ◽

Self Similarity ◽

Fractal Characteristic ◽

Electrical Tree ◽

Breakdown Phenomenon ◽

Electrical Trees ◽

Electrical Treeing

<div class="WordSection1"><p>One of the degradations of insulation is in the form of electrical treeing in which classified as a pre-breakdown phenomenon of electrical insulation. The electrical tree is commonly forming in the shape of tree-like or root-like which may have fractal structures. Due to this fractal structure, electrical treeing formation and patterns are analysed via fractal dimension and lacunarity to study the self-similarity patterns of electrical treeing. Many types of research have been conducted to study the fractal dimension and lacunarity of electrical treeing to fully understand the electrical tree mechanism and characteristics. However, fractal and lacunarity structures of</p></div>

Download Full-text

Enhancing the power generation of Rhodopseudomonas palustris-based MFC

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209444 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 1261-1268

Author(s):

Shu Otani ◽

Dang-Trang Nguyen ◽

Kozo Taguchi

Keyword(s):

Activated Carbon ◽

Rhodopseudomonas Palustris ◽

Ozone Treatment ◽

Maximum Power Density ◽

On Demand ◽

Long Time ◽

Dry Conditions ◽

Carbon Sheet ◽

Uv Ozone

In this study, a portable and disposable paper-based microbial fuel cell (MFC) was fabricated. The MFC was powered by Rhodopseudomonas palustris bacteria (R. palustris). An activated carbon sheet-based anode pre-loaded organic matter (starch) and R. palustris was used. By using starch in the anode, R. palustris-loaded on the anode could be preserved for a long time in dry conditions. The MFC could generate electricity on-demand activated by adding water to the anode. The activated carbon sheet anode was treated by UV-ozone treatment to remove impurities and to improve its hydrophilicity before being loaded with R. palustris. The developed MFC could generate the maximum power density of 0.9 μW/cm2 and could be preserved for long-term usage with little performance degradation (10% after four weeks).

Download Full-text

Radiated Electro-Magnetic Waves Caused by Electrical Tree Development in Epoxy Resin

IEEJ Transactions on Fundamentals and Materials ◽

10.1541/ieejfms.129.915 ◽

2009 ◽

Vol 129 (12) ◽

pp. 915-921 ◽

Cited By ~ 5

Author(s):

Hideki Ueno ◽

Takashi Nagamachi ◽

Masaki Nakamura ◽

Hiroshi Nakayama ◽

Kunihiko Kakihana

Keyword(s):

Epoxy Resin ◽

Electrical Tree ◽

Electro Magnetic ◽

Tree Development ◽

Magnetic Waves

Download Full-text

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

Sensors ◽

10.3390/s21072562 ◽

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.

Download Full-text

Effect of Alumina and Halloysite clay on Electrical tree growth in Silicone Rubber Nanocomposite

Journal of Engineering and Science Research ◽

10.26666/rmp.jesr.2018.3.4 ◽

2018 ◽

Vol 2 (3) ◽

pp. 20-25

Author(s):

Keyword(s):

Tree Growth ◽

Silicone Rubber ◽

Strength Properties ◽

Growth Speed ◽

New Approach ◽

Undoped Material ◽

Electrical Tree ◽

Nano Alumina ◽

Tree Growth Rate ◽

Insulation Breakdown

Nowadays Silicone Rubber (SiR) is recommended in high voltage cable accessories fabrication as it offers excellent electrical and mechanical properties. Electrical tree is one of the phenomenon which contributes to the main factor of SiR insulation breakdown. Recently, a new approach has been applied in order to enhance the insulation strength properties by introducing nano filler in undoped material. Thus, this paper presents the influence of nano-alumina and halloysite nanoclay on electrical tree growth in SiR at 0, 1 vol%, 2 vol% and 3 vol% concentration. The electrical tree growth was investigated at 8kVrms after tree inception voltage (TIV) within 30 minutes under room temperature. The results show reductions of electrical tree growth speed and accumulate damage (%) up to 2 vol% nano-alumina and up to 3 vol% halloysite nanoclay. Nevertheless the presence of 3 vol% nano-alumina in SiR leads to the faster electrical tree growth rate and the worst accumulate damage within 1 minute of electrical tree growth process.

Download Full-text

Inhibition of Rejuvenation Liquid on Trees in XLPE Cables under Switching Impulse Voltages

Energies ◽

10.3390/en12112133 ◽

2019 ◽

Vol 12 (11) ◽

pp. 2133

Author(s):

Guangya Zhu ◽

Kai Zhou ◽

Wei Gong ◽

Min He ◽

Jiaming Kong ◽

...

Keyword(s):

Average Length ◽

Substantial Reduction ◽

Accelerated Aging ◽

Inhibitory Effect ◽

Control Group ◽

Initiation Rate ◽

Water Tree ◽

Electrical Tree ◽

Electrical Trees ◽

Two Parameters

In this paper, the inhibitory effect of preinjected rejuvenation liquid on trees in cross-linked polyethylene (XLPE) cables was investigated. Experimental samples were prepared by inserting needles into XLPE samples, and many equally-spaced holes existed in the outer semiconductive layer. All cable samples were divided into two groups. One sample group was treated with rejuvenation liquid, while the other group was the control group. A tree accelerated aging system was used to obtain trees in the XLPE cable samples. During the aging experiment, an impulse voltage was applied to the samples repeatedly. The micromorphologies of the two groups were observed. Based on the micromorphologies, two parameters were determined: the initiation rate of electrical trees and the average length of trees. Furthermore, the electric field distribution was simulated to analyze the initiation of electrical trees. The results indicate that an electrical tree is much harder to initiate in the pretreated XLPE cables than in the untreated cables. This phenomenon is likely attributed to the dielectrophoretic forces in the pretreated cables. Moreover, rejuvenation liquid deposited in XLPE causes a substantial reduction in the Maxwell stress of molecular chains. Rejuvenation liquid inhibits electrical tree initiation and water tree growth to a great extent.

Download Full-text

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

Materials ◽

10.3390/ma13245722 ◽

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.

Download Full-text

Electrical Treeing in Power Cable Insulation under Harmonics Superimposed on Unfiltered HVDC Voltages

Energies ◽

10.3390/en12163113 ◽

2019 ◽

Vol 12 (16) ◽

pp. 3113 ◽

Cited By ~ 3

Author(s):

Mehrtash Azizian Fard ◽

Mohamed Emad Farrag ◽

Alistair Reid ◽

Faris Al-Naemi

Keyword(s):

Electric Fields ◽

Direct Current ◽

Asset Management ◽

Diagnostic Techniques ◽

Power Cable ◽

Operational Parameters ◽

Cable Insulation ◽

Electrical Tree ◽

Double Electrode ◽

Electrical Trees

Insulation degradation is an irreversible phenomenon that can potentially lead to failure of power cable systems. This paper describes the results of an experimental investigation into the influence of direct current (DC) superimposed with harmonic voltages on both partial discharge (PD) activity and electrical tree (ET) phenomena within polymeric insulations. The test samples were prepared from a high voltage direct current (HVDC) cross linked polyethylene (XLPE) power cable. A double electrode arrangement was employed to produce divergent electric fields within the test samples that could possibly result in formation of electrical trees. The developed ETs were observed via an optical method and, at the same time, the emanating PD pulses were measured using conventional techniques. The results show a tenable relation between ETs, PD activities, and the level of harmonic voltages. An increase in harmonic levels has a marked effect on development of electrical trees as the firing angle increases, which also leads to higher activity of partial discharges. This study of the influencing operational parameters of HVDC converters on power cable insulation is predicted to contribute to enhancements in cable design and progressive advancement in condition monitoring and insulation diagnostic techniques that can lead to more effective asset management in HVDC systems.

Download Full-text

Study on the Fractal Dimension and Growth Time of the Electrical Treeing Degradation at Different Temperature and Moisture

Advances in Materials Science and Engineering ◽

10.1155/2018/6019269 ◽

2018 ◽

Vol 2018 ◽

pp. 1-10

Author(s):

Youping Fan ◽

Dai Zhang ◽

Jingjiao Li

Keyword(s):

Fractal Dimension ◽

Tree Growth ◽

Fractal Dimensions ◽

Moisture Level ◽

Growth Time ◽

Counting Method ◽

Box Counting ◽

Electrical Trees ◽

Box Counting Method ◽

Electrical Treeing

The paper aims to understand how the fractal dimension and growth time of electrical trees change with temperature and moisture. The fractal dimension of final electrical trees was estimated using 2-D box-counting method. Four groups of electrical trees were grown at variable moisture and temperature. The relation between growth time and fractal dimension of electrical trees were summarized. The results indicate the final electrical trees can have similar fractal dimensions via similar tree growth time at different combinations of moisture level and temperature conditions.

Download Full-text