scholarly journals Charge Injection Characteristics of Semi-Conductive Composites with Carbon Black-Polymer for HVDC Cable

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1134 ◽  
Author(s):  
Yanhui Wei ◽  
Mingyue Liu ◽  
Wang Han ◽  
Guochang Li ◽  
Chuncheng Hao ◽  
...  
Keyword(s):  
Carbon Black ◽  
Electric Field ◽  
Bottom Electrode ◽  
Charge Injection ◽  
Experimental Results ◽  
Uniform Electric Field ◽  
Insulation Material ◽  
Electrode Structure ◽  
Depolarization Current ◽  
Conductive Composites

Semi-conductive composites composed of carbon black-polymer play an important role in uniform electric field in high voltage direct current (HVDC) cable. They also affect space charge behaviors in the insulation material. However, the charge injection characteristics of semi-conductive composites are not detailed. In this work, the electrode structure of ‘Semi-conductive composites- Insulation material- Metal bottom’ (S-I-M) is proposed, and the currents formed by injected charges from semi-conductive composites are characterized by the thermally stimulated depolarization current (TSDC) method. Further, the experimental results based on the structure of S-I-M are compared with the traditional electrode structure of M-I-M (Metal upper electrode- Insulation material- Metal bottom electrode) and the simplified cable electrode structure of MS-I-M (Metal upper electrode-Semi-conductive electrode- Insulation material- Metal bottom electrode), respectively. The experimental results show that the semi-conductive composite plays an important role in the charge injection process and it presents a different tendency under different compound modes of temperature and electric field. For the low electric field (E ≤ 5 kV/mm) and the low temperature (T ≤ 50 °C), the current caused by the accumulated charges follows the rule, IS > IMS > IM. For the low electric field and high temperature (T > 50 °C), the current caused by the injected charges follows the rule, IMS > IM > IS. This phenomenon is closely related to the interface characterization and contact barrier.

scholarly journals Synthesis of a Novel Semi-Conductive Composites Doping with La0.8Sr0.2MnO3 for Excellent Electric Performance for HVDC Cable

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 809 ◽  
Author(s):  
Hongxia Yin ◽  
Yingcao Cui ◽  
Yanhui Wei ◽  
Chuncheng Hao ◽  
Qingquan Lei
Keyword(s):  
Electric Field ◽  
Space Charge ◽  
Charge Injection ◽  
Inhibitory Effect ◽  
Uniform Electric Field ◽  
Positive Temperature ◽  
Ptc Effect ◽  
Suppression Effect ◽  
Conductive Composites ◽  
Conductive Particles

The semi-conductive layer located between the wire core and the insulation layer in high voltage direct current (HVDC) cable plays a vital role in uniform electric field and affecting space charges behaviors. In this work, the research idea of adding ionic conductive particles to semi-conductive materials to improve the conductive network and reduce the energy of the moving charge inside it and to suppress charge injection was proposed. Semi-conductive composites doped with different La0.8Sr0.2MnO3 (LSM) contents were prepared. Resistivity at different temperatures was measured to investigate the positive temperature coefficient (PTC) effect. Pulse electro-acoustic (PEA) method and thermal-stimulation depolarization currents (TSDC) tests of the insulation layers were carried out. From the results, space charge distribution and TSDC currents in the insulation samples were analyzed to evaluate the inhibitory effect on space charge injection. When LSM content is 6 wt. %, the experimental results show that the PTC effect of the specimen and charge injection are both being suppressed significantly. The maximum resistivity of it is decreased by 53.3% and the insulation sample has the smallest charge amount, 1.85 × 10−7 C under 10 kV/mm—decreased by 40%, 3.6 × 10−7 C under 20 kV/mm—decreased by 45%, and 6.42 × 10−7 C under 30 kV/mm—decreased by 26%. When the LSM content reaches 10 wt. %, the suppression effect on the PTC effect and the charge injection are both weakened, owing to the agglomeration of the conductive particles inside the composites which leads to the interface electric field distortion and results in charge injection enhancement.

Design, fabrication and characterization of dielectrophoretic microelectrode array for particle capture

2015 ◽  
Vol 32 (2) ◽  
pp. 96-102 ◽  
Author(s):  
M.R. Buyong ◽  
J. Yunas ◽  
A.A. Hamzah ◽  
B. Yeop Majlis ◽  
F. Larki ◽  
...  
Keyword(s):  
Electric Field ◽  
Microelectrode Array ◽  
Metal Structure ◽  
Uniform Electric Field ◽  
Particle Capture ◽  
Electrode Structure ◽  
Peak Voltage ◽  
Content Type ◽  
Mems Fabrication ◽  
Array Structures

Purpose – The purpose of this study is to design and characterize the dielectrophoretic (DEP) microelectrodes with various array structure arrangements in order to produce optimum non-uniform electric field for particle capture. The DEP-electrodes with 2D electrode structure was fabricated and characterized to see the effect of electrode structure configuration on the capture capability of the cells suspending in the solution. Design/methodology/approach – The presented microelectrode array structures are made of planar conductive metal structure having same size and geometry. Dielectrophoretic force (FDEP) generated in the fluidic medium is initially simulated using COMSOL Multi-physics performed on two microelectrodes poles, which is then continued on three-pole microelectrodes. The proposed design is fabricated using standard MEMS fabrication process. Furthermore, the effect of different sinusoidal signals of 5, 10 and 15 volt peak to peak voltage (Vpp) at fixed frequency of 1.5 MHz on capturing efficiency of microelectrodes were also investigated using graphite metalloids particles as the suspended particles in the medium. The graphite particles that are captured at the microelectrode edges are characterized over a given time period. Findings – Based on analysis, the capturing efficiency of microelectrodes at the microelectrode edges is increased as voltage input increases, confirming its dependency to the FDEP strength and direction of non-uniform electric field. This dependency to field consequently increases the surface area of the accumulated graphite. It is also showed that the minimum ratio of the surface accumulated area of captured graphite is 1, 2.75 and 9 μm2 for 5, 10 and 15 Vpp, respectively. The simulation result also indicates a significant improvement on the performance of microelectrodes by implementing third pole in the design. The third pole effect the particles in the medium by creating stronger non-uniform electric field as well as more selective force toward the microelectrodes’ edges. Originality/value – The microelectrode array arrangement is found as a reliable method to increase the strength and selectivity of non-uniform electric field distribution that affect FDEP. The presented findings are verified through experimental test and simulation results.

Interface electric field of carbon black loaded electrode and its significant influence on charge injection into polyethylene

2011 ◽  
Vol 123 (5) ◽  
pp. 3017-3022 ◽  
Author(s):  
Chun Xiao ◽  
Yewen Zhang ◽  
Zhenlian An ◽  
Feihu Zheng ◽  
Wenjie Wei ◽  
...  
Keyword(s):  
Carbon Black ◽  
Electric Field ◽  
Significant Influence ◽  
Charge Injection

scholarly journals Effect of Semi-Conductive Layer Modified by Magnetic Particle SrFe12O19 on Charge Injection Characteristics of HVDC Cable

Polymers ◽  
2019 ◽  
Vol 11 (8) ◽  
pp. 1309 ◽  
Author(s):  
Yanhui Wei ◽  
Mingyue Liu ◽  
Jiaxing Wang ◽  
Guochang Li ◽  
Chuncheng Hao ◽  
...  
Keyword(s):  
Space Charge ◽  
Magnetic Particles ◽  
Charge Injection ◽  
Direct Access ◽  
Polarization Current ◽  
Insulation Material ◽  
Conductive Layer ◽  
Depolarization Current ◽  
Steady State Current ◽  
Secondary Injection

For high voltage direct current (HVDC) cable, a semi-conductive layer lies between the conductor and the insulation layer; as the charge migrates the path from the conductor to the insulation material, it will affect space charge injection. In this work, the research idea of changing the injection path of moving charges within semi-conductive layer by magnetic particles was proposed. Semi-conductive composites with different SrFe12O19 contents of 1 wt.%, 5 wt.%, 10 wt.%, 20 wt.%, and 30 wt.% were prepared, and the amount of injected charges in the insulation sample was characterized by space charge distribution, polarization current, and thermally-stimulated depolarization current. The experimental results show that a small amount of SrFe12O19 can significantly reduce charge injection in the insulation sample, owing to the deflection of the charge migration path, and only part of the electrons can enter the insulation sample. When the content is 5 wt.%, the insulation sample has the smallest charge amount, 0.89 × 10−7 C, decreasing by 37%, and the steady-state current is 6.01 × 10−10 A, decreasing by 22%. When SrFe12O19 content exceeds 10 wt.%, the charge suppression effect is not obvious and even leads to the increase of charge amount in the insulation sample, owing to the secondary injection of charges. Most moving charges will deflect towards the horizontal direction and cannot direct access to the insulation sample, resulting in a large number of charges accumulation in the semi-conductive layer. These charges will seriously enhance the interface electric field near the insulation sample, leading to the secondary injection of charges, which are easier to inject into the insulation sample.

INFLUENCE OF SHEAR ON THE DIELECTRIC CONSTANT OF LIQUIDS

1951 ◽  
Vol 29 (10) ◽  
pp. 848-856 ◽  
Author(s):  
B. L. Funt ◽  
S. G. Mason
Keyword(s):  
Dielectric Constant ◽  
Liquid Crystals ◽  
Carbon Black ◽  
Electric Field ◽  
Velocity Gradient ◽  
Ethyl Cellulose ◽  
Experimental Results ◽  
Particle Orientation ◽  
Nonpolar Solvents ◽  
Polar Polymers

The effects of a velocity gradient upon the dielectric constant were studied in solutions of macromolecules, in suspensions and in liquid crystals. Decreases in dielectric constant under shear were observed for polar polymers in polar and nonpolar solvents. For solutions of ethyl cellulose an increase in dielectric constant was obtained. Nonpolar polymers showed no changes of dielectric constant under shear. Large changes in dielectric constant at low rates of shear were observed in carbon black suspensions. The experimental results are discussed on the basis of particle orientation in a velocity gradient and in an electric field.

UNCHARGED CONDUCTING TOROIDAL RING IN A UNIFORM ELECTRIC FIELD

1961 ◽  
Vol 39 (10) ◽  
pp. 1495-1500
Author(s):  
S. C. Loh
Keyword(s):  
Electric Field ◽  
Potential Function ◽  
Systematic Study ◽  
Theoretical Calculations ◽  
Numerical Results ◽  
Experimental Results ◽  
Uniform Electric Field ◽  
University Of Toronto ◽  
Mathematical Expressions ◽  
The University

Mathematical expressions for the potential function of an uncharged conducting toroidal ring placed in a uniform electric field are derived and expressed in terms of toroidal functions. Some numerical results were calculated by the IBM 650 computer at the University of Toronto and are included in the present paper. To verify the calculated results, a systematic study of an electrolytic tank was undertaken. It was found that the theoretical calculations agreed well with the experimental results.

scholarly journals Research on Creeping Flashover Characteristics of Nanofluid-Impregnated Pressboard Modified Based on Fe3O4 Nanoparticles under Lightning Impulse Voltages

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 524 ◽  
Author(s):  
Bingliang Shan ◽  
Meng Huang ◽  
Yupeng Ying ◽  
Mingkang Niu ◽  
Qian Sun ◽  
...  
Keyword(s):  
Electric Field ◽  
Fe3o4 Nanoparticles ◽  
Breakdown Strength ◽  
Transformer Oil ◽  
Uniform Electric Field ◽  
Surface Charges ◽  
Depolarization Current ◽  
Before And After ◽  
Lightning Impulse ◽  
Thermally Stimulated Depolarization

Creeping flashover of mineral-oil-impregnated pressboard under impulse stress is a common insulating failure in oil-immersed transformers, arousing increasing attention. Recent studies have shown that the breakdown strength of transformer oil under positive lightning impulse voltage can be significantly improved through nanoparticles-based modification, and Fe3O4 has shown the best improvement in breakdown strength compared to other nanoparticles that have been used. This paper presents the creeping flashover characteristics of pure oil-impregnated pressboard (OIP) and nanofluid-impregnated pressboard (NIP) based on Fe3O4 nanoparticles under positive and negative lightning impulse voltages, respectively. It was found that NIP possessed higher resistance to creeping flashover than OIP. The relative permittivities of oil and oil-impregnated pressboard before and after nanoparticles-based modification were measured, and the results revealed that the addition of nanoparticles led to a better match in relative permittivity between oil and oil-impregnated pressboard, and a more uniform electric field distribution. Furthermore, the shallow trap density in NIP was obviously increased compared to that of OIP through the thermally stimulated depolarization current (TSDC), which promoted the dissipation of surface charges and weakened the distortion of the electric field. Therefore, the creeping flashover characteristics of oil-impregnated pressboard were greatly improved with Fe3O4 nanoparticles.

Bubble motion in liquid nitrogen under a non-uniform electric field in a microgravity environment

1997 ◽  
Vol 117 (11) ◽  
pp. 1109-1114
Author(s):  
Yoshiyuki Suda ◽  
Kenji Mutoh ◽  
Yosuke Sakai ◽  
Kiyotaka Matsuura ◽  
Norio Homma
Keyword(s):  
Electric Field ◽  
Liquid Nitrogen ◽  
Microgravity Environment ◽  
Uniform Electric Field ◽  
Bubble Motion
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