Method of calculating the dielectric loss tangent of binary systems

1987 ◽  
Vol 52 (3) ◽  
pp. 310-312
Author(s):  
G. N. Dul'nev ◽  
D. P. Volkov ◽  
M. V. Dobrochasov
2021 ◽  
Vol 14 (2) ◽  
pp. 132-141
Author(s):  
M. N. Lyutikova ◽  
S. M. Korobeynikov ◽  
A. A. Konovalov

Power transformers are key equipment in power generation, transmission, and distribution systems. The reliability of power transformers is based on the performance of the insulation system, which includes solid cellulose insulation and a liquid dielectric. Modern power engineering requires liquid insulation to have excellent insulating properties, high fire resistance, and biodegradability. Mineral oil that has been in use for over 100 years does not meet certain requirements. Therefore, various methods of enhancing the insulating properties of the oil are currently being considered, including mixing it with other liquid dielectrics, which have excellent properties. Synthetic and natural esters are considered as alternative fluids.This article discusses the possibility of enhancing the insulating characteristics of mineral oil with a high content of aromatic hydrocarbons (for example, T-750 oil) by mixing it with synthetic ester Midel 7131. Assessment is given of insulating parameters of the resulting mixtures with an ester fraction in mineral oil from 0% to fifty%. The main characteristics of the mixtures are described, such as density, kinematic viscosity, flash point, dielectric loss tangent, relative dielectric permittivity, breakdown voltage, and moisture content. It is shown that with an increase in the proportion of ester, some parameters of the obtained insulating liquid improve (flash point, dielectric constant, breakdown voltage), while values of other parameters (density, kinematic viscosity, dielectric loss tangent) with an ester content of more than 10% in the mixture do not meet the requirements for mineral oils.


2015 ◽  
Vol 39 (1) ◽  
pp. 1-12 ◽  
Author(s):  
AKM Zakaria ◽  
Faizun Nesa ◽  
MA Saeed Khan ◽  
SM Yunus ◽  
NI Khan ◽  
...  

The spinel ferrites MgCrxFe2-xO4 (0.0 ? × ?1.0) were prepared through the solid state reaction using conventional ceramic method at 1300°C in air. The homogeneous phase of the ferrite samples was observed from the X-ray diffraction study. Lattice parameter of the samples was found to decrease with increasing Cr concentration in the system obeying Vegard’s law. The ac electrical resistivity, measured as a function of temperature, decreases with the increase of temperature indicating the semiconducting nature of all the samples. The activation energies were calculated and found to decrease with increasing Cr content. The lower activation energies are associated with higher electrical conductivity. With the increase of temperature, dielectric constant (e`) and dielectric loss tangent are observed to be increased; while with the increase of frequency, dielectric constant (e`) and dielectric loss tangent decrease for all the samples.Journal of Bangladesh Academy of Sciences, Vol. 39, No. 1, 1-12, 2015


2020 ◽  
Vol 21 (10) ◽  
pp. 2407-2416
Author(s):  
Koviljka A. Asanovic ◽  
Dragana D. Cerovic ◽  
Mirjana M. Kostic ◽  
Tatjana V. Mihailovic ◽  
Aleksandra M. Ivanovska

1998 ◽  
Vol 71 (5) ◽  
pp. 281-285 ◽  
Author(s):  
Toyohiko GONDOH ◽  
Yukiko MATSUOKA ◽  
Michiharu TOH ◽  
Daisaburo OKAI ◽  
Tetsuo MORI

2002 ◽  
Vol 377 (3) ◽  
pp. 313-318 ◽  
Author(s):  
M. Kusunoki ◽  
M. Inadomaru ◽  
S. Ohshima ◽  
K. Aizawa ◽  
M. Mukaida ◽  
...  

2018 ◽  
Vol 15 (1) ◽  
pp. 48-54
Author(s):  
Jeevan S. Ghodake

Dysprosium substituted Magnesium ferrite weresuccessfully prepared by chemical combustion method. The as synthesized powder was presintered in air at 6000C for 1hr and finally sintered at 9500C for 1hr. From X-ray powder diffraction pattern of MgDy0.03Fe1.97O4, confirmed formation of single phase cubic spinel structure. The value of crystallite size obtained from X-ray powder diffraction (311) peak , it is found to be 46.38nm.The frequency and temperature variation of dielectric parameters such as real dielectric constant (ε′), complex dielectric constant (ε") and dielectric loss tangent (tanδ) were determined using Hioki LCR - Q meter. The frequency variation of dielectric constant shows a normal dielectric behavior of spinel ferrites. The dielectric loss tangent with frequency shows similar behavior as dielectric constant. The dielectric constant and dielectric loss tangent increases with increase in temperature


2006 ◽  
Vol 9 (6) ◽  
pp. 485-489
Author(s):  
Satoru AMOU ◽  
Akira NAGAI ◽  
Akio TAKAHASHI ◽  
Yoshihiro NAKAMURA

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