Investigation on the Characteristics of Cap and Pin Glass Insulator due to Effect of Contamination

2015 ◽  
Vol 793 ◽  
pp. 95-99
Author(s):  
O. Mardianaliza ◽  
Melaty Amirruddin ◽  
F.S. Abdullah ◽  
Noor Anida
Keyword(s):  
Leakage Current ◽  
Breakdown Voltage ◽  
Laboratory Experiments ◽  
Experimental Results ◽  
Contamination Level ◽  
Voltage Distribution ◽  
Insulator Surface ◽  
Wet Condition ◽  
Dry Conditions ◽  
Glass Insulator

This article investigates the characteristics of cap and pin glass insulator and its enhancement due to contamination particles or elements by means of laboratory experiments. The insulator surface is simulated for dry conditions as well as its changes under wet conditions. To find the influence of the contamination layers on the leakage current and voltage distribution, various levels of the ESDD of the insulators were applied in the study. Additionally, experimental results show that the higher contamination level of insulator may have lower breakdown voltage especially in wet condition.

Numerical Simulation of Leakage Current on Conductive Insulator Surface

2019 ◽  
Vol 8 (4) ◽  
pp. 9487-9492
Keyword(s):  
Numerical Simulation ◽  
Electric Field ◽  
Leakage Current ◽  
Method Of Lines ◽  
Electron Attachment ◽  
Negative Ions ◽  
Conduction Current ◽  
Insulator Surface ◽  
Finite Difference Approximations ◽  
Positive Ions

The outdoor insulator is commonly exposed to environmental pollution. The presence of water like raindrops and dew on the contaminant surface can lead to surface degradation due to leakage current. However, the physical process of this phenomenon is not well understood. Hence, in this study we develop a mathematical model of leakage current on the outdoor insulator surface using the Nernst Planck theory which accounts for the charge transport between the electrodes (negative and positive electrode) and charge generation mechanism. Meanwhile the electric field obeys Poisson’s equation. Method of Lines technique is used to solve the model numerically in which it converts the PDE into a system of ODEs by Finite Difference Approximations. The numerical simulation compares reasonably well with the experimental conduction current. The findings from the simulation shows that the conduction current is affected by the electric field distribution and charge concentration. The rise of the conduction current is due to the distribution of positive ion while the dominancy of electron attachment with neutral molecule and recombination with positive ions has caused a significant reduction of electron and increment of negative ions.

scholarly journals A Novel Gate Drive Circuit for Suppressing Turn-on Oscillation of Non-Kelvin Packaged SiC MOSFET

Energies ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2449
Author(s):  
Hongyan Zhao ◽  
Jiangui Chen ◽  
Yan Li ◽  
Fei Lin
Keyword(s):  
Thermal Conductivity ◽  
Breakdown Voltage ◽  
Basic Principle ◽  
Double Pulse ◽  
Experimental Results ◽  
Switching Frequency ◽  
Turn On ◽  
Proof Testing ◽  
Gate Driver ◽  
Drive Circuit

Compared with a silicon MOSFET device, the SiC MOSFET has many benefits, such as higher breakdown voltage, faster action speed and better thermal conductivity. These advantages enable the SiC MOSFET to operate at higher switching frequencies, while, as the switching frequency increases, the turn-on loss accounts for most of the loss. This characteristic severely limits the applications of the SiC MOSFET at higher switching frequencies. Accordingly, an SRD-type drive circuit for a SiC MOSFET is proposed in this paper. The proposed SRD-type drive circuit can suppress the turn-on oscillation of a non-Kelvin packaged SiC MOSFET to ensure that the SiC MOSFET can work at a faster turn-on speed with a lower turn-on loss. In this paper, the basic principle of the proposed SRD-type drive circuit is analyzed, and a double pulse platform is established. For the purpose of proof-testing the performance of the presented SRD-type drive circuit, comparisons and experimental verifications between the traditional gate driver and the proposed SRD-type drive circuit were conducted. Our experimental results finally demonstrate the feasibility and effectiveness of the proposed SRD-type drive circuit.

Microstructure and Electrical Properties of ZnO-Pr6O11-Dy2O3-Based Varistor Ceramics Doped with La2O3

2007 ◽  
Vol 336-338 ◽  
pp. 680-683
Author(s):  
Jing Nan Cai ◽  
Yuan Hua Lin ◽  
Rong Juan Zhao ◽  
Ce Wen Nan ◽  
Jin Liang He
Keyword(s):  
Rare Earth ◽  
Phase Composition ◽  
Electrical Properties ◽  
Rare Earth Elements ◽  
Leakage Current ◽  
Breakdown Voltage ◽  
Intergranular Phase ◽  
Ceramic Method ◽  
Sem Micrographs ◽  
Ceramic Samples

ZnO-Pr6O11-Dy2O3-based varistor ceramics doped with 0~1.5 mol% La2O3 were fabricated by a conventional ceramic method. All the samples were sintered at 1350 oCfor 2 h. The phase composition and microstructure of the ceramic samples have been investigated by XRD, SEM and EDS. The results of SEM micrographs indicated that the La2O3 additives can promote ZnO grain’s growth, and the rare earth elements dispersed mainly in the intergranular phase observed by EDS. The electrical properties of the samples determined by the V-I curves revealed that the breakdown voltage of samples decreases from 508 V/mm to about 100 V/mm with the increase of La2O3, and the nonlinear exponent also decreases from 20.2 to 13.2. The typical leakage current is about 10.2 μA for the sample doped with 0.5 mol% La2O3.

Characteristics of Hydraulic Shock Waves in an Inclined Chute Contraction - Experiments

2009 ◽  
Vol 25 (1) ◽  
pp. 129-136 ◽  
Author(s):  
C.-D. Jan ◽  
C.-J. Chang ◽  
J.-S. Lai ◽  
W.-D. Guo
Keyword(s):  
Experimental Data ◽  
Shock Waves ◽  
Froude Number ◽  
Inclination Angle ◽  
Laboratory Experiments ◽  
Deflection Angle ◽  
Experimental Results ◽  
Regression Analyses ◽  
Hydraulic Shock ◽  
Empirical Relations

AbstractThis paper presents the experimental results of the characteristics of hydraulic shock waves in an inclined chute contraction with consideration of the effects of sidewall deflection angle φ, bottom inclination angle θ and approach Froude number Fr0. Seventeen runs of laboratory experiments were conducted in the range of 27.45° ≤φ ≤ 40.17°, 6.22° ≤ θ ≤ 25.38° and 1.04 ≤ Fr0 ≤ 3.51. Based on the experimental data, three empirical dimensionless relations for the shock angle, maximum shockwave height, and corresponding position of maximum shockwave were obtained by regression analyses, respectively. These empirical relations would be useful for hydraulic engineers in designing chute contraction structures.

The Research on Deposition Saturation of Disc Suspension Porcelain Insulator

2014 ◽  
Vol 986-987 ◽  
pp. 1881-1883
Author(s):  
Tian Shu Hai ◽  
Qing Hao Wang ◽  
Chang Xin Ge ◽  
Shao Yong Wu ◽  
Peng Fei Cheng ◽  
...  
Keyword(s):  
Lower Surface ◽  
Comparison Method ◽  
Experimental Results ◽  
Salt Deposit ◽  
Porcelain Insulator ◽  
Saturation Time ◽  
Insulator Surface ◽  
Suspension Insulator ◽  
Actual Operation ◽  
Deposit Density

The equivalent salt deposit density (ESDD) is an important characteristic of our country which is used to measure insulator deposition level. The contamination of the insulator would reach saturation after a period of time.In order to increase the specific creepage distance, disc suspension porcelain insulator lower surface inward concave, which makes the rain washing the upper surface difficult, that cause the saturation time of lower surface longer than upper surface .For studying the operation insulator contamination saturation time and reflecting the ESDD of the actual operation line accurately,this paper adopts a comparison method between empty hanging insulator surface and operation insulator surface to measure the ESDD , the field experimental results further verify that the saturated time of disc suspension insulator lower surface is longer, so as to lay the foundation for the ESDD measurement.

The 3D graph approach for breakdown voltage calculation in BaTiO3 ceramics

2021 ◽  
pp. 2150103
Author(s):  
Vojislav V. Mitic ◽  
Branislav Randjelovic ◽  
Ivana Ilic ◽  
Srdjan Ribar ◽  
An-Lu Chun ◽  
...  
Keyword(s):  
Graph Theory ◽  
Crystal Structures ◽  
Breakdown Voltage ◽  
Main Idea ◽  
Experimental Results ◽  
Grain Structure ◽  
Mathematical Approach ◽  
Electronic Parameters ◽  
Mathematical Graph

After pioneering attempts for the introduction of graph theory in the field of ceramics and microstructures, where 1D and 2D graphs were used, in this paper we applied 3D graphs for the breakdown voltage calculation in BaTiO3 sample with some predefined constraints. We have described the relations between grains in the sample and established a mathematical approach for the calculation of breakdown voltage using experimental results. As a result, we introduced mapping between the property of sample and grain structure, then between the grain structure and mathematical graph, using various crystal structures. The main idea was to apply 3D graph theory for the distribution of electronic parameters between the neighboring grains. With this study, we successfully confirmed the possibilities for applications of graphs as a tool for the determination of properties even at the intergranular level.

scholarly journals A MODEL FOR BREACH GROWTH IN A DIKE-BURST

1988 ◽  
Vol 1 (21) ◽  
pp. 140 ◽  
Author(s):  
Paul J. Visser
Keyword(s):  
Mathematical Model ◽  
The Netherlands ◽  
Laboratory Experiments ◽  
Suspended Load ◽  
Experimental Results ◽  
Sand Transport ◽  
Model Predictions ◽  
Pumped Storage

A mathematical model for sand-dike breach erosion is presented. The heart of the model is a modified Bagnold (1963) energetics—based sand transport conception combined with a simplified Galappatti and Vreugdenhil (1985) pick up mechanism for the suspended load. The model has been tested to three laboratory experiments. The agreement between model predictions and experimental results is surprisingly good. Prototype calculations are presented for the 73 m high sand—dike of a proposed pumped—storage plant in the Netherlands.

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