Analyzing the Volume Charge Accumulation during Avalanche-to-Streamer Transitions in Air in Strong Uniform Electric Fields

2020 ◽  
Vol 4 (4) ◽  
pp. 10-15
Author(s):  
Andrey A. BELOGLOVSKY ◽  
◽  
Sergey V. BELOUSOV ◽  
Keyword(s):  
Electric Fields ◽  
Volume Charge ◽  
Charge Accumulation

Modeling of Physical and Chemical Processes of Anodic Bonding Technology

2014 ◽  
Vol 1040 ◽  
pp. 513-518 ◽  
Author(s):  
N.S. Pshchelko ◽  
M.P. Sevryugina
Keyword(s):  
Electric Fields ◽  
Chemical Processes ◽  
Anodic Bonding ◽  
Charge Accumulation ◽  
Charge Layer ◽  
Bonding Technology ◽  
Time Required ◽  
A Charge ◽  
Physical And Chemical ◽  
Kinetics Of

Modeling ideas of physical and chemical processes when using an anodic bonding for materials connection are developed. The kinetics of a charge accumulation in an electrode region in a dielectric is considered. The thickness of a charge layer, electric fields strength and value of the ponderomotive pressure providing connection of materials are calculated. It is shown that the necessary ponderomotive pressure resulting in a dielectric-to-conductor seal is normally about ten MPa and the time required is about ten minutes.

scholarly journals Electrochromism of Viologen/Polymer Composite: From Gel to Insulating Bulk for High-Voltage Applications

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5901
Author(s):  
Yongjie Nie ◽  
Meng Zhang ◽  
Yuanwei Zhu ◽  
Yu Jing ◽  
Wenli Shi ◽  
...  
Keyword(s):  
Power Systems ◽  
Space Charge ◽  
Electric Fields ◽  
High Voltage ◽  
Vinylidene Fluoride ◽  
Power Equipment ◽  
Charge Accumulation ◽  
Charge Detection ◽  
Continuous Current ◽  
High Electric Fields

Power equipment operates under high voltages, inducing space charge accumulation on the surface of key insulating structures, which increases the risk of discharge/breakdown and the possibility of maintenance workers experiencing electric shock accidents. Hence, a visualized non-equipment space charge detection method is of great demand in the power industry. Typical electrochromic phenomenon is based on redox of the material, triggered by a voltage smaller than 5 V with a continuous current in μA~mA level, which is not applicable to high electric fields above 106 V/m with pA~nA operation current in power equipment. Until now, no naked-eye observation technique has been realized for space charge detection to ensure the operation of power systems as well as the safety of maintenance workers. In this work, a viologen/poly(vinylidene fluoride-co-hexafluoropropylene)(P(VDF–HFP)) composite is investigated from gel to insulating bulk configurations to achieve high-voltage electrical-insulating electrochromism. The results show that viologen/P(VDF–HFP) composite bulk can withstand high electric fields at the 107 V/m level, and its electrochromism is triggered by space charges. This electrochromism phenomenon can be visually extended by increasing viologen content towards 5 wt.% and shows a positive response to voltage amplitude and application duration. As viologen/P(VDF–HFP) composite bulk exhibits a typical electrical insulating performance, it could be attached to the surface of insulating structures or clamped between metal and insulating materials as a space charge accumulation indicator in high-voltage power equipment.

scholarly journals Polyethylene/Graphene Nanoplatelet Nanocomposite-Based Insulating Materials for Effective Reduction of Space Charge Accumulation in High-Voltage Direct-Current Cables

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Ji Sun Park ◽  
Young Sun Kim ◽  
Hyun-Jung Jung ◽  
Daseul Park ◽  
Jee Young Yoo ◽  
...  
Keyword(s):  
Space Charge ◽  
Electric Fields ◽  
Healing Process ◽  
Field Enhancement ◽  
Hydrophobic Surface ◽  
Threshold Concentration ◽  
Charge Accumulation ◽  
Organic Modifiers ◽  
Defect Healing ◽  
Optical Absorption Measurement

We have demonstrated a straightforward hydrophobic surface modification of graphene nanoplatelets (GNPs) through a defect-healing process to fabricate well-dispersed insulating low-density polyethylene (LDPE)/GNP nanocomposites and have confirmed their effective suppression of space charge accumulation. Without any organic modifiers, GNPs containing oxygen-based functional groups at the edges were successfully reduced at optimal high-temperature defect-healing condition and modified to have hydrophobic surface properties similar to those of the LDPE matrix. The degree of dispersion and the reproducibility of the mechanically melt-mixed LDPE/GNP nanocomposites were immediately analyzed by thickness-normalized optical absorption measurement. In the LDPE matrix, below the percolation threshold concentration, well-dispersed GNP fillers effectively acted as trapping sites under high electric fields, resulting in the successful suppression of packet-like space charge accumulation (field enhancement factor=1.04 @ 0.1 wt% LDPE/GNP nanocomposite).

scholarly journals Долговечность полимеров в переменном электрическом поле

2020 ◽  
Vol 90 (2) ◽  
pp. 251
Author(s):  
В.А. Закревский ◽  
В.А. Пахотин ◽  
Н.Т. Сударь
Keyword(s):  
Free Radicals ◽  
Excited States ◽  
Electric Fields ◽  
Charge Accumulation ◽  
Nonradiative Relaxation ◽  
Polymer Dielectric ◽  
Ac Electric Fields ◽  
Ac Field ◽  
The Difference ◽  
Electron Excited States

An explanation of the difference in the electrical properties of polymers in the DC and AC electric fields is proposed. Energy release during recombination of electrons and holes injected into a polymer dielectric is considered as a factor accelerating the processes of electric aging of these dielectrics in an AC field. It is shown that nonradiative relaxation of electron excited states causes breaks of bonds in macromolecules and formation of free radicals. Due to the lower ionization energy of free radicals (compared to the original molecules), the rate of charge accumulation in the polymer dielectric increases, which leads to a decrease in its durability in an AC field compared to the durability of polymers in a DC field.

Improving Amorphous Selenium Photodetector Performance Using an Organic Semiconductor

2013 ◽  
Vol 543 ◽  
pp. 451-454 ◽  
Author(s):  
Shiva Abbaszadeh ◽  
Nicholas Allec ◽  
Karim S. Karim
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Short Pulse ◽  
Amorphous Selenium ◽  
Semiconductor Materials ◽  
Manufacturing Processes ◽  
Charge Accumulation ◽  
Dark Current Density ◽  
Large Area ◽  
High Electric Fields

In this paper, a thin layer of perylene tetracarboxylic bisbenzimidazole (PTCBI) is investigated as a potential hole-blocking contact in an a-Se photodetector. The behavior of the device was characterized as a function of electric field under light and dark conditions. It was found that the PTCBI layer permits operation at high electric fields (>>10 V/μm) while maintaining a dark current density below 200 pA/mm2. Short pulse experiments were performed to assure that charge accumulation at the organic/a-Se interface is negligible and does not reduce the electric field in the a-Se layer. The detector investigated uses a simple low temperature fabrication process based on widely available semiconductor materials that can be easily integrated into current large area digital imager manufacturing processes.

Influence of the Radiation Destruction of Polymeric Insulation on its Ageing in the Impulse Electric Field

2014 ◽  
Vol 880 ◽  
pp. 88-92 ◽  
Author(s):  
Peter N. Bychkov ◽  
Olga V. Solodovnikova
Keyword(s):  
Service Life ◽  
Radiation Resistance ◽  
Molecular Level ◽  
Gas Permeability ◽  
Low Density Polyethylene ◽  
Low Density ◽  
Volume Charge ◽  
Charge Accumulation ◽  
Gaseous Products ◽  
Ionizing Radiations

Sensitivity of the destructive doses of ionizing radiations, specifically radiolysis gaseous products to multipulse electric intensity of low-density polyethylene (LDPE) and a polymethyl-methacrylate (PMMA) was investigated. LDPE and PMMA were found to differ significantly depending on radiation resistance and gas permeability. The service life of the materials was basically determined by the intensity of the destruction processes at the molecular level, the macrodefects were developed at the last ageing stage . It was shown that microseconds impulses did not cause accumulation of volume charge in LDPE and PMMA. It was concluded that the ageing of polymer dielectrics affected by electric microseconds impulses did not relate to volume charge accumulation in the polymers.

scholarly journals Surface Charge Properties of Epoxy Composites under DC Voltage Affected by Surface and Bulk Conductivity

Energies ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 370
Author(s):  
Qian Wang ◽  
Xidong Liang ◽  
Ke Chen ◽  
Chao Wu ◽  
Shan Liu
Keyword(s):  
Electric Field ◽  
Surface Charge ◽  
Epoxy Resin ◽  
Electric Fields ◽  
Surface Resistivity ◽  
Resin Composites ◽  
Charge Accumulation ◽  
Electrode Structure ◽  
Epoxy Resin Composites ◽  
High Electric Fields

As DC transmission voltage increases, the DC wall bushing becomes longer, and a supporting insulator is introduced to keep the conductor straight. Under extremely high electric fields coupled with a thermal gradient, the surface charge of the supporting insulator may distort the field distribution and increase the risk of flashover. In this paper, surface potentials of three model epoxy resin composites were systematically investigated under varied voltage amplitudes, different voltage polarities and electric field distributions. The bulk and surface resistivity of the epoxy resin composites over a broad temperature range were measured to reveal the correlations between surface charge and such basic electrical parameters. The results indicate that the normal-dominated electric field plays the major role in charge accumulation. The processes of surface charge accumulation and dissipation are more closely related to the surface resistivity. As a result, the surface charge properties can be improved by optimizing the electrode structure and resistivity of the epoxy resin composites.

Control of Metal Alloy Oxidation with Electric Fields

1973 ◽  
Vol 31 ◽  
pp. 164-165
Author(s):  
R. R. Dils ◽  
P. S. Follansbee
Keyword(s):  
Electric Fields ◽  
Oxidation Process ◽  
Base Alloy ◽  
Oxide Surface ◽  
Platinum Electrodes ◽  
Insulating Layer ◽  
Iron Base Alloy ◽  
Alloy Oxidation ◽  
Aluminum Oxide Layer ◽  
And Control

Electric fields have been applied across oxides growing on a high temperature alloy and control of the oxidation of the material has been demonstrated. At present, three-fold increases in the oxidation rate have been measured in accelerating fields and the oxidation process has been completely stopped in a retarding field.The experiments have been conducted with an iron-base alloy, Pe 25Cr 5A1 0.1Y, although, in principle, any alloy capable of forming an adherent aluminum oxide layer during oxidation can be used. A specimen is polished and oxidized to produce a thin, uniform insulating layer on one surface. Three platinum electrodes are sputtered on the oxide surface and the specimen is reoxidized.

Electron-Mirror Microscopic Aspects of Ferroelectric Domains of BaTiO3 And Ca2Sr (C2H5CO2)6

1970 ◽  
Vol 28 ◽  
pp. 478-479
Author(s):  
Teruo Someya ◽  
Jinzo Kobayashi
Keyword(s):  
Surface Layer ◽  
Electric Fields ◽  
Quantitative Study ◽  
Recent Progress ◽  
Ferroelectric Domain ◽  
Resolving Power ◽  
Surface Pattern ◽  
Crystal Surfaces ◽  
One Dimensional ◽  
Ferroelectric Domains

Recent progress in the electron-mirror microscopy (EMM), e.g., an improvement of its resolving power together with an increase of the magnification makes it useful for investigating the ferroelectric domain physics. English has recently observed the domain texture in the surface layer of BaTiO3. The present authors ) have developed a theory by which one can evaluate small one-dimensional electric fields and/or topographic step heights in the crystal surfaces from their EMM pictures. This theory was applied to a quantitative study of the surface pattern of BaTiO3).

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