Pollution Flashover Characteristics of Coated Insulators under Different Profiles of Coating Damage

Based on experiments and numerical analysis techniques, this paper aims to investigate the influence of the four different coating damage profiles on the performance of coated 33 kV porcelain insulator strings under polluted and clean surface conditions. The performance of the insulators coated with room temperature vulcanizing (RTV) under partial coating damage and undamaged coating was evaluated. The influence of humidity on pollution flashover was taken into consideration. The ring-shaped, fan-shaped, and random-shaped coating was applied following coating damage. The results showed that the flashover characteristic of the RTV-coated insulators had a significant difference as compared to the normal insulators. Electrical characteristics such as the flashover voltage, critical current, and surface resistance were significantly affected by coating damage distribution and humidity level on the insulators’ surface. The electric field and potential difference were analyzed as well using the finite element method (FEM). The initiation of the arc was observed to appear at the area of insulators where the electric field was the highest. It was also observed that different coating distributions of pollution and humidity levels resulted in a change in the surface pollution layer resistance and an uneven distribution of the electric field. This indicates that the coated insulators’ parameters are directly related to the coating damage distribution on the insulator surface, particularly in the presence of humidity.

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Pollution morphology characteristics on a superhydrophobic surface and its pollution flashover voltage in DC electric field

High Voltage ◽

10.1049/hve2.12165 ◽

2021 ◽

Author(s):

Yijie Liu ◽

Yujun Guo ◽

Bo Wang ◽

Xueqin Zhang ◽

Guizao Huang ◽

...

Keyword(s):

Electric Field ◽

Superhydrophobic Surface ◽

Pollution Flashover ◽

Flashover Voltage ◽

Dc Electric Field ◽

Morphology Characteristics

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Membrane thickening of water works sludge

Water Science & Technology Water Supply ◽

10.2166/ws.2001.0117 ◽

2001 ◽

Vol 1 (5-6) ◽

pp. 215-220

Author(s):

A. Gillighan ◽

S.J. Judd ◽

R. Eyres

Keyword(s):

Hydraulic Resistance ◽

Reasonable Agreement ◽

Chemical Cleaning ◽

Solids Concentration ◽

Significant Difference ◽

Layer Resistance ◽

Tubular Membranes ◽

Resistance Data ◽

Mechanical Cleaning ◽

Dynamic Layer

The efficacy of ultrafiltration (UF) and microfiltration (MF) membranes was assessed for the concentration of actual waterworks sludges using crossflow tubular membranes operated at constant trans-membrane pressure. The MF membrane gave higher initial fluxes than the UF membrane but after 10 min of filtration the flux value and its decline tended to be very similar for both membranes operating under the same conditions. All membranes gave permeate product water of <0.2 NTU and <100ppb coagulant at all times. For both membranes mechanical cleaning, with sponge balls, was at least as effective as acid chemical cleaning, indicating that no significant permanent internal fouling occurred for these membrane materials. Hydraulic resistance data indicated a significant difference in the dynamic layer resistance between the two membranes. Whilst the UF membrane had a hydraulic resistance 3.7 times that of the MF membrane, the dynamic layer formed on the UF membrane during operation displayed a maximum hydraulic resistance almost nine times lower than that of the MF membrane operating under the same conditions. Correlation of cake resistance R versus feed solids concentration C for all the data generated for t>0 demonstrated reasonable agreement with the expression R∝ca where a=0.37 in the current study. This trend has been recorded in previous reported studies, a varying between 0.33 and 0.62 depending on sludge dewaterability.

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Near Room‐Temperature Large Electrocaloric Effect in Barium Titanate Single Crystal Based on Electric Field‐Temperature Phase Diagram

physica status solidi (RRL) - Rapid Research Letters ◽

10.1002/pssr.202100251 ◽

2021 ◽

Author(s):

Junjie Li ◽

Zhonghua Li ◽

Jingjin He ◽

Yuxuan Hou ◽

Yanjing Su ◽

...

Keyword(s):

Phase Diagram ◽

Barium Titanate ◽

Electric Field ◽

Single Crystal ◽

Room Temperature ◽

Temperature Phase ◽

Electrocaloric Effect ◽

Field Temperature ◽

Temperature Phase Diagram

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Development of 8 mΩ-cm2, 1.8 kV 4H-SiC DMOSFETs

Materials Science Forum ◽

10.4028/www.scientific.net/msf.527-529.1261 ◽

2006 ◽

Vol 527-529 ◽

pp. 1261-1264 ◽

Cited By ~ 10

Author(s):

Sei Hyung Ryu ◽

Sumi Krishnaswami ◽

Brett A. Hull ◽

Bradley Heath ◽

Mrinal K. Das ◽

...

Keyword(s):

Threshold Voltage ◽

Room Temperature ◽

Elevated Temperatures ◽

Gate Length ◽

Gate Bias ◽

Low Loss ◽

Layer Resistance ◽

Switching Characteristics ◽

Mos Gate ◽

Drift Layer

8 mΩ-cm2, 1.8 kV power DMOSFETs in 4H-SiC are presented in this paper. A 0.5 μm long MOS gate length was used to minimize the MOS channel resistance. The DMOSFETs were able to block 1.8 kV with the gate shorted to the source. At room temperature, a specific onresistance of 8 mΩ-cm2 was measured with a gate bias of 15 V. At 150 oC, the specific onresistance increased to 9.6 mΩ-cm2. The increase in drift layer resistance due to a decrease in bulk electron mobility was partly cancelled out by the negative shift in MOS threshold voltage at elevated temperatures. The device demonstrated extremely fast, low loss switching characteristics. A significant improvement in converter efficiency was observed when the 4H-SiC DMOSFET was used instead of an 800 V silicon superjunction MOSFET in a simple boost converter configuration.

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Electric Field Dependence of the Fluorescence Intensity of Solute Molecules and Fourth Order Effects

Zeitschrift für Naturforschung A ◽

10.1515/zna-1985-0902 ◽

1985 ◽

Vol 40 (9) ◽

pp. 874-876

Author(s):

Hilmar Bischof ◽

Wolfram Baumann

Keyword(s):

Electric Field ◽

External Electric Field ◽

Field Dependence ◽

Fourth Order ◽

Fluorescence Intensity ◽

Room Temperature ◽

Order Effects ◽

Electric Field Dependence ◽

Total Fluorescence

Abstract The effect of an external electric field on the total fluorescence of solute molecules is studied up to fourth order theoretically, and is checked experimentally with 4´-N,N-dimethylamino- 4-nitrostilbene in dioxane at room temperature.

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Calculations of the electric field distribution in a TEM cell by the finite element method

6th International SYmposium on Antennas, Propagation and EM Theory, 2003. Proceedings. 2003 ◽

10.1109/isape.2003.1276808 ◽

2003 ◽

Author(s):

Tieren Zhang

Keyword(s):

Finite Element Method ◽

Finite Element ◽

Electric Field ◽

Field Distribution ◽

Electric Field Distribution ◽

The Finite Element Method ◽

Tem Cell ◽

Element Method

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Introduction of Fine Engineered Domain Configuration into Potassium Niobate Single Crystals

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.350.89 ◽

2007 ◽

Vol 350 ◽

pp. 89-92

Author(s):

Keisuke Yokoh ◽

Tomomitsu Muraishi ◽

Song Min Nam ◽

Hirofumi Kakemoto ◽

Takaaki Tsurumi ◽

...

Keyword(s):

Electric Field ◽

Single Crystals ◽

Room Temperature ◽

Single Domain ◽

Potassium Niobate ◽

Field Exposure ◽

Domain State ◽

Domain Configuration ◽

Dc Electric Field ◽

Direction Of Polarization

To induce fine engineered domain configurations into potassium niobate (KNbO3) single crystals, two kinds of methods were performed, i.e., (1) high DC electric field exposure along the opposite direction of polarization of KNbO3 single-domain crystals at room temperature, and (2) introduction of randomly oriented fine domain configuration by heat treatment at 700 °C and then high DC electric field exposure along [001]c direction of KNbO3 multidomain crystals at room temperature. When the method (1) was performed, finally, the poled KNbO3 crystals became to single-domain state again through the formation of multidomain state. On the other hand, the KNbO3 multidomain crystals were obtained by using the method (2), and an enhancement of piezoelectric-related properties was observed.

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