Electric‐Field Distribution in Pulsed High‐Current‐Density Discharges in Helium and Helium‐Hydrogen Mixtures

1969 ◽  
Vol 40 (2) ◽  
pp. 675-681 ◽  
Author(s):  
Frank Allario ◽  
Nathan Wainfan
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Current Density ◽  
Electric Field Distribution ◽  
High Current Density ◽  
High Current ◽  
Hydrogen Mixtures

scholarly journals Analysis of Electric Field and Current Density for Different Electrode Configuration of XLPE Insulation

2018 ◽  
Vol 7 (3.36) ◽  
pp. 127 ◽  
Author(s):  
Nishanthi Sunthrasakaran ◽  
Nor Akmal Mohd Jamail ◽  
Qamarul Ezani Kamarudin ◽  
Sujeetha Gunabalan
Keyword(s):  
Electric Field ◽  
Power System ◽  
Field Distribution ◽  
High Voltage ◽  
Current Density ◽  
Electric Field Distribution ◽  
Electrical Power ◽  
High Electric Field ◽  
Electrode Configuration ◽  
Maximum Electric Field

The most important aspect influencing the circumstance and characteristics of electrical discharges is the distribution of electric field in the gap of electrodes. The study of discharge performance requires details on the variation of maximum electric field around the electrode. In electrical power system, the insulation of high voltage power system usually subjected with high electric field. The high electric field causes the degradation performance of insulation and electrical breakdown start to occur. Generally, the standard sphere gaps widely used for protective device in electrical power equipment. This project is study about the electric field distribution and current density for different electrode configuration with XLPE barrier. Hence, the different electrode configuration influences the electric field distribution. This project mainly involves the simulation in order to evaluate the maximum electric field for different electrode configuration. Finite Element Method (FEM) software has been used in this project to perform the simulation. This project also discusses the breakdown characteristics of the XLPE. The accurate evaluation of electric field distribution and maximum electric field is an essential for the determination of discharge behavior of high voltage apparatus and components. The degree of uniformity is very low for pointed rod-plane when compared to other two electrode configurations. The non- uniform electric distribution creates electrical stress within the surface of dielectric barrier. As a conclusion, when the gap distance between the electrodes increase the electric field decrease.  

scholarly journals On the question of using solid electrodes in the electrolysis of cryolite-alumina melts. Part 3. Electric field distribution on the electrodes

2021 ◽  
Vol 25 (2) ◽  
pp. 235-251
Author(s):  
E. S. Gorlanov ◽  
A. A. Polyakov
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Edge Effect ◽  
Current Density ◽  
Molten Salts ◽  
Functional Relationship ◽  
Electric Field Distribution ◽  
Chemical Inhomogeneity ◽  
Electrolytic Process ◽  
Solid Electrodes

The aim of this work is to identify the theoretical limitations of molten salts electrolysis using solid electrodes to overcome these limitations in practice. We applied the theory of electric field distribution on the electrodes in aqueous solutions to predict the distribution of current density and potential on the polycrystalline surface of electrodes in molten salts. By combining the theoretical background of the current density distribution with the basic laws of potential formation on the surface of the electrodes, we determined and validated the sequence of numerical studies of electrolytic processes in the pole gap. The application of the method allowed the characteristics of the current concentration edge effect at the periphery of smooth electrodes and the distribution of current density and potential on the heterogeneous electrode surface to be determined. The functional relationship and development of the electrolysis parameters on the smooth and rough surfaces of electrodes were established by the different scenario simulations of their interaction. It was shown that it is possible to reduce the nonuniformity of the current and potential distribution on the initially rough surface of electrodes with an increase in the cathode polarisation, alumina concentration optimisation and melt circulation. It is, nonetheless, evident that with prolonged electrolysis, physical and chemical inhomogeneity can develop, nullifying all attempts to stabilise the process. We theoretically established a relationship between the edge effect and roughness and the distribution of the current density and potential on solid electrodes, which can act as a primary and generalising reason for their increased consumption, passivation and electrolytic process destabilisation in standard and low-melting electrolytes. This functional relationship can form a basis for developing the methods of flattening the electric field distribution over the anodes and cathodes area and, therefore, stabilising the electrolytic process. Literature overview, laboratory tests and theoretical calculations allowed the organising principle of a stable electrolytic process to be formulated -the combined application of elliptical electrodes and the electrochemical micro-borating of the cathodes. Practical verification of this assumption is one direction for further theoretical and laboratory research.

Electrostatic and Electrodynamic Field Analyses of 33kV Line Insulators

2006 ◽  
Vol 7 (3) ◽  
Author(s):  
Ibrahim A. Metwally ◽  
Md Abdus Salam ◽  
Ali Al-Maqrashi ◽  
Saif AR Sumry ◽  
Saif SH Al-Harthy
Keyword(s):  
Electric Field ◽  
Current Density ◽  
High Current Density ◽  
Experimental Tests ◽  
Finite Element Models ◽  
High Current ◽  
Density Profiles ◽  
Fully Integrated ◽  
Software Modules ◽  
Simulation Results

Electrostatic and electrodynamic field analyses of 33kV line insulators were introduced to compare the electric-field and the current density profiles of commonly used line insulators in Oman; namely, silicone rubber (SiR) and porcelain line post insulators, and porcelain cap and pin insulator string. SLIM software package was used for such simulation, which is a fully integrated collection of software modules that provides facilities for the generation and solution of electromagnetic finite element models. The simulation results reveal that for the electrostatic simulation under pollution conditions, SiR and porcelain line-post insulators give maximum values of the electric field of 360kV/m and 1700kV/m, respectively. The latter value exceeds the recommended electric field level of 500kV/m. For the electrodynamic simulation under pollution conditions, the electric field and the current density are much higher for porcelain insulator compared to those of SiR insulator. The simulation of four cap-pin standard insulator string reveals that there is high electric field (1250kV/m) at the cap-insulator gap which can cause high current density for polluted case. Finally, the trend of the simulation results has been verified by experimental tests, which has been conducted on different 33kV line insulators having different designs and materials.

Void Elongation Phenomena Observed in Polycrystalline Cu Interconnects at a High Current Density Stressing Conditions

1997 ◽  
Vol 473 ◽  
Author(s):  
S. Shingubara ◽  
S. Kajiwara ◽  
T. Osaka ◽  
H. Sakaue ◽  
T. Takahagi
Keyword(s):  
Image Analysis ◽  
Electric Field ◽  
Grain Boundaries ◽  
Morphological Change ◽  
Current Density ◽  
Elevated Temperatures ◽  
High Current Density ◽  
High Current ◽  
Cu Interconnects ◽  
Electric Field Direction

ABSTRACTFormation and morphological change of voids induced by electromigration in polycrystalline Cu interconnects on TiN have been investigated at various current density conditions at elevated temperatures. At first voids were formed at grain boundaries, then they grew further to elongate in the electric field direction. Void elongation parameter (a ratio of void diameters in longitudinal to lateral directions to the electric field) was 2.53 when the current density was 9×106A/cm2, while it was 1.31 when the current density was 3×106A/cm2at 400°C, 50h. Occurrence of void elongation is enhanced with increase in current density, and its relationship to grain boundaries are discussed by FIB-SIM image analysis.

scholarly journals Time-Dependent Electric Field Distribution in Layered Paper-Oil Insulation

2019 ◽  
pp. 58-63 ◽  
Author(s):  
Gunnar Håkonseth ◽  
Erling Ildstad
Keyword(s):  
Electric Field ◽  
Field Distribution ◽  
Electric Fields ◽  
Current Density ◽  
Test Object ◽  
Dielectric Response ◽  
Electric Field Distribution ◽  
Time Dependent ◽  
Polarization Current ◽  
Dependent Polarization

Layered paper–oil insulation is used in several types of HVDC equipment. In order to better understand breakdown mechanisms and optimize the design, it is important to understand the electric field distribution in the insulation. In the present work, a test object with such insulation has been modeled as a series connection of oil and impregnated paper. The permittivity, conductivity, and the dielectric response function has been measured for impregnated paper and oil separately and used as parameters in a dielectric response model for the layered insulation system. A system of differential equations has been established describing the voltages across each material, i.e. across each layer of the test object. These equations have been solved considering a DC step voltage across the whole test object. Based on this, the time-dependent electric field in each material as well as the time-dependent polarization current density in the test object have been calculated. The calculated polarization current density was found to agree well with the measured polarization current density of the test object. This indicates that application of dielectric response theory gives a good estimate of the time-dependent electric field distribution in layered insulation systems. The results show that 90 % of the change from initial values to steady-state values for the electric fields has occurred within the first 35 minutes after the voltage step. This applies to the electric fields in both of the materials of the examined test object at a temperature of 323 K.

Area-Optimized JTE for 4.5 kV Non Ion-Implanted 4H-SiC BJT

2013 ◽  
Vol 740-742 ◽  
pp. 974-977 ◽  
Author(s):  
Arash Salemi ◽  
Hossein Elahipanah ◽  
Benedetto Buono ◽  
Carl Mikael Zetterling ◽  
Mikael Östling
Keyword(s):  
Electric Field ◽  
Ion Implantation ◽  
Field Distribution ◽  
Breakdown Voltage ◽  
Contact Area ◽  
Electric Field Distribution ◽  
Current Gain ◽  
High Current ◽  
High Breakdown Voltage ◽  
Base Contact

Non ion-implantation mesa etched 4H-SiC BJT with three-zone JTE of optimized lengths and doses (descending sequences) has been simulated. This design presents an efficient electric field distribution along the device. The device area has been optimized and considerably reduced. As a result of this comprehensive optimization, a high breakdown voltage and high current gain have been achieved; meanwhile the device area with a constant emitter and base contact area has been reduced by about 30%.

Numrical Simulation on Electric Field of Galvanic Corrosion for U-Nb Alloy and 45-Steel

2013 ◽  
Vol 749 ◽  
pp. 556-560
Author(s):  
Ping Dong ◽  
Zhen Pu ◽  
Mao Bin Shuai
Keyword(s):  
Electric Field ◽  
Current Density ◽  
Electric Potential ◽  
Galvanic Corrosion ◽  
High Current Density ◽  
Potential Drop ◽  
Corrosion Current ◽  
High Current ◽  
Electrode Size ◽  
Corrosion Medium

Based on the galvanic corrosion experiment for U-Nb alloy and 45-steel in the 3.5 mass percent NaCl solutions, the galvanic corrosion electric field has been calculated by finite element method. The electric potential and the current density evolution during galvanic corrosion have been obtained. The results show that the electric potential drop between cathode and anode had obvious difference. The electric potential drop in the U-Nb alloy cathode is higher than that in the 45-steel anode, which makes the electric field in the U-Nb alloy higher than that in the 45-steel. A rather high current density exists at the ends and corners of the specimen. The permittivity of the corrosion medium only has a little effect on the corrosion electric potential, but has obvious effects on the corrosion current density. The electrode size has obvious effects on the corrosion electric potential and current density.

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