Dependence of the electrical breakdown voltage on the charging time inValonia utricularis

1980 ◽  
Vol 53 (1) ◽  
pp. 33-43 ◽  
Author(s):  
U. Zimmermann ◽  
R. Benz
Keyword(s):  
Breakdown Voltage ◽  
Electrical Breakdown ◽  
Charging Time

Effect of Water on Electrical Properties of Refined, Bleached, and Deodorized Palm Oil (RBDPO) as Electrical Insulating Material

2013 ◽  
Vol 64 (4) ◽  
Author(s):  
Nazera Ismail ◽  
Yanuar Z. Arief ◽  
Zuraimy Adzis ◽  
Shakira A. Azli ◽  
Abdul Azim A. Jamil ◽  
...  
Keyword(s):  
Electrical Properties ◽  
Breakdown Voltage ◽  
Palm Oil ◽  
Pour Point ◽  
Electrical Breakdown ◽  
Dissipation Factor ◽  
Mineral Oil ◽  
Flash Point ◽  
Effect Of Water ◽  
Insulating Liquid

This paper describes the properties of refined, bleached, deodorized palm oil (RBDPO) as having the potential to be used as insulating liquid. There are several important properties such as electrical breakdown, dielectric dissipation factor, specific gravity, flash point, viscosity and pour point of RBDPO that was measured and compared to commercial mineral oil which is largely in current use as insulating liquid in power transformers. Experimental results of the electrical properties revealed that the average breakdown voltage of the RBDPO sample, without the addition of water at room temperature, is 13.368 kV. The result also revealed that due to effect of water, the breakdown voltage is lower than that of commercial mineral oil (Hyrax). However, the flash point and the pour point of RBDPO is very high compared to mineral oil thus giving it advantageous possibility to be used safely as insulating liquid. The results showed that RBDPO is greatly influenced by water, causing the breakdown voltage to decrease and the dissipation factor to increase; this is attributable to the high amounts of dissolved water.

Influence of cathode material type on the electrical breakdown behaviors of DC discharge

2020 ◽  
Vol 98 (8) ◽  
pp. 726-731
Author(s):  
F. Diab ◽  
W.H. Gaber ◽  
M.E. Abdel-kader ◽  
B.A. Soliman ◽  
M.A. Abd Al-Halim
Keyword(s):  
Cathode Material ◽  
Work Function ◽  
Breakdown Voltage ◽  
Cathode Materials ◽  
Electrical Breakdown ◽  
Ionization Efficiency ◽  
Parallel Plates ◽  
Maximum Value ◽  
Dc Discharge ◽  
Work Functions

Paschen curves were studied using different cathode materials such as magnesium, zinc, and carbon graphite by discharge in argon gas of a pressure range between 0.08 and 3 Torr using a parallel plates configuration. The first and second Townsend coefficients (α and γ, respectively) and the ionization efficiency (η) of different cathode materials were deduced from Paschen curves as a function of the reduced field (E/P). The minimum breakdown voltage was found to be about 242 V for Mg material, which has the lowest work function, while carbon graphite has a higher breakdown voltage of 283 V due to its higher work function. The second coefficient γ was increased as a function of E/P and has higher values for materials of lower work functions, and a similar trend of γ is obtained as a function of the ion mean energy. On the other hand, the first coefficient α has a reverse behavior with both E/P and the work function of the cathode materials compared with the second coefficient. The ionization efficiency of the three cathode materials is identical, as η depends only on the gas properties and not the cathode material. η has a maximum value of about 0.025 V−1 for an E/P of about 185 Vcm−1Torr−1, corresponding to the maximum ionizing ability of electrons. The validation of the breakdown results has been confirmed by conferring with other published experimental measurements.

scholarly journals Fabrication of Fe3O4@SiO2 Nanofluids with High Breakdown Voltage and Low Dielectric Loss

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 716
Author(s):  
Bin Du ◽  
Yu Shi ◽  
Qian Liu
Keyword(s):  
Dielectric Loss ◽  
Breakdown Voltage ◽  
Shell Thickness ◽  
Electrical Breakdown ◽  
Sio2 Nanoparticles ◽  
Electrical Equipment ◽  
Insulating Oil ◽  
Low Dielectric ◽  
Sio2 Shell ◽  
High Dielectric

Insulating oil modified by nanoparticle (often called nanofluids) has recently drawn considerable attention, especially concerning the improvement of electrical breakdown and thermal conductivity of the nanofluids. However, traditional insulating nanofluid often tends to high dielectric loss, which accelerates the ageing of nanofluids and limits its application in electrical equipment. In this paper, three core-shell Fe3O4@SiO2 nanoparticles with different SiO2 shell thickness were prepared and subsequently dispersed into insulating oil to achieve nanofluids. The dispersion stability, breakdown voltages and dielectric properties of these nanofluids were comparatively investigated. Experimental results show the alternating current (AC) and positive lightning breakdown voltage of nanofluids increased by 30.5% and 61%, respectively. Moreover, the SiO2 shell thickness of Fe3O4@SiO2 nanoparticle had significant effects on the dielectric loss of nanofluids.

Electrical Breakdown Voltage In a Mixed Gas

2001 ◽  
Vol 40 (Part 2, No. 3B) ◽  
pp. L295-L297 ◽  
Author(s):  
Han S. Uhm ◽  
Eun H. Choi ◽  
Guansup Cho ◽  
Ki W. Whang
Keyword(s):  
Breakdown Voltage ◽  
Electrical Breakdown ◽  
Mixed Gas

Experimental Study on Electromechanical Failure of Dielectric Elastomer Actuator

2015 ◽  
Author(s):  
Xuejing Liu ◽  
Shuhai Jia ◽  
Hualing Chen ◽  
Bo Li ◽  
Yu Xing
Keyword(s):  
Breakdown Voltage ◽  
Failure Modes ◽  
Dielectric Breakdown ◽  
Electrical Breakdown ◽  
Dielectric Elastomer ◽  
Theoretical Explanation ◽  
Special Focus ◽  
Stress Effect ◽  
Deformation State ◽  
Boundary Stress

The dielectric elastomer (DE) is an insulating membrane with extra-ordinary properties which can meet various electromechanical failures during the actuation. In the current work, we measured breakdown voltage in DE membrane with special focus on the varying boundary stress during the actuation process. The boundary stress tuned deformation state, causing the membrane to deform out-of-plane before breakdown. A theoretical model is presented, involving the strain-stiffening effect in material and boundary stress effect in geometry, to estimate the dielectric breakdown voltage. The results agree with the experiments. Then, another set of experimental investigation is conducted to study the voltage-induced wrinkling of DE membrane. Steady wrinkles, without an accompany of electrical breakdown are attained and three different failure modes of DE membrane are classified into a phase chart. Finally, a qualitative theoretical explanation on wrinkling mechanism of DE membrane is presented and verified by experimental observations.

THE ELECTRICAL BREAKDOWN OF SMALL GAPS IN VACUUM

1958 ◽  
Vol 36 (4) ◽  
pp. 476-493 ◽  
Author(s):  
A. S. Denholm
Keyword(s):  
Time Dependence ◽  
Breakdown Voltage ◽  
Discharge Current ◽  
Electrical Breakdown ◽  
Vacuum Discharge ◽  
Diffusion Pump ◽  
Hydrogen Discharge ◽  
Impulse Voltage ◽  
Vacuum Gap ◽  
Plateau Level

An investigation of the electrical breakdown in vacuum of small gaps subject to contamination by diffusion pump oil showed that the most consistent results were obtained when electrodes were conditioned by a hydrogen discharge. Even with this method of conditioning a few preliminary sparks were usually required before the breakdown voltage reached a plateau level, so that the vacuum discharge itself could affect the final values obtained. The circuit parameters which controlled the discharge current were found to influence the magnitude and consistency of the breakdown voltage appreciably.Direct, alternating, and impulse voltage tests showed that the time for which voltage was applied to the vacuum gap influenced the breakdown voltage, and curves are presented which give the insulation strength of the gap. Two possible explanations of the time dependence of the breakdown voltage are given.

scholarly journals Effect of repeated electrical breakdowns on mineral and natural ester insulating oils

2021 ◽  
Vol 10 (6) ◽  
pp. 2989-2996
Author(s):  
Sharin Ab Ghani ◽  
Mohd Shahril Ahmad Khiar ◽  
Imran Sutan Chairul ◽  
Muhammad Imran Zamir
Keyword(s):  
Breakdown Voltage ◽  
Electrical Discharge ◽  
Electrical Breakdown ◽  
Standard Test ◽  
Test Method ◽  
Power Transformers ◽  
Insulating Oil ◽  
Different Types ◽  
Increasing Demand ◽  
Natural Ester

Transformer insulating oils are exposed to repeated electrical discharge or breakdowns inside power transformers. Durability tests are conducted to analyze the ability of oil to resist decomposition due to such high electrical stresses. With the increasing demand for alternative insulating oils for oil-immersed transformers, it is worthy to compare the performance of different types of insulating oils (conventional mineral-based insulating oil and natural ester-based insulating oil) under repeated electrical breakdown. In this paper, the AC breakdown voltage of different mineral-based and natural ester-based insulating oils is reported. Durability tests were conducted based on the AC breakdown voltage behavior of insulating oils after 50 electrical breakdown shots. The AC breakdown voltage of each insulating oil sample was assessed according to the ASTM D1816 standard test method. Based on the results, it can be concluded that the dissimilarity in chemical composition of the insulating oils has a significant effect on the AC breakdown voltage behavior of these oils under repeated electrical breakdowns.

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