Characteristics of streamers developing at inception voltage in small gaps of natural ester, synthetic ester and mineral oil under lightning impulse

2016 ◽  
Vol 10 (1) ◽  
pp. 50-57 ◽  
Author(s):  
Pawel Rozga ◽  
Marcin Stanek
Keyword(s):  
Mineral Oil ◽  
Synthetic Ester ◽  
Lightning Impulse ◽  
Inception Voltage ◽  
Natural Ester

scholarly journals Influence of Molecule Structure on Lightning Impulse Breakdown of Ester Liquids

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1061
Author(s):  
Huaqiang Li ◽  
Linfeng Xia ◽  
Shengwei Cai ◽  
Zhiqiang Huang ◽  
Jiaqi Li ◽  
...  
Keyword(s):  
Electric Fields ◽  
Breakdown Voltage ◽  
Experimental Research ◽  
Environmentally Friendly ◽  
Mineral Oil ◽  
Positive Polarity ◽  
Mineral Oils ◽  
Synthetic Ester ◽  
Lightning Impulse ◽  
Natural Ester

Ester liquids are environmentally friendly insulating oils, and they can be used as an alternative to mineral oil in transformers, even though in most countries spills of ester oils must be treated like spills of mineral oil. Furthermore, the breakdown characteristics of ester liquids are worse than those of mineral oils in heterogeneous electric fields. In this paper, we present a comprehensive experimental research on both positive and negative lightning impulse breakdown properties in point-plane geometries with gaps varying from 1 mm to 50 mm. The breakdown voltages and streamer velocities of five kinds of ester liquids, including natural ester, synthetic ester, and three kinds of single component esters have been measured. The results show that the double bonds have no effect on the breakdown voltage of ester liquids. The average streamer velocities of mono-esters are faster than that of other esters under positive polarity, and the breakdown voltages of all esters are close.

scholarly journals Dielectric properties of natural ester, synthetic ester midel 7131 and mineral oil diala D

2014 ◽  
Vol 21 (2) ◽  
pp. 644-652 ◽  
Author(s):  
Yi Jing ◽  
Igor Timoshkin ◽  
Mark Wilson ◽  
Martin Given ◽  
Scott Macgregor ◽  
...  
Keyword(s):  
Dielectric Properties ◽  
Mineral Oil ◽  
Synthetic Ester ◽  
Natural Ester

scholarly journals Effect of Moisture on the Thermal Conductivity of Cellulose and Aramid Paper Impregnated with Various Dielectric Liquids

Energies ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 4433 ◽  
Author(s):  
Grzegorz Dombek ◽  
Zbigniew Nadolny ◽  
Piotr Przybylek ◽  
Radoslaw Lopatkiewicz ◽  
Agnieszka Marcinkowska ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Linear Equation ◽  
Heat Transport ◽  
Mineral Oil ◽  
Experimental Database ◽  
Synthetic Ester ◽  
Dielectric Liquids ◽  
Paper Insulation ◽  
The Impact ◽  
Natural Ester

This paper presents the effect of the impact of moisture in paper insulation used as insulation of transformer windings on its thermal conductivity. Various types of paper (cellulose and aramid) and impregnated (mineral oil, synthetic ester, and natural ester) were tested. The impact of paper and impregnated types on the changes in thermal conductivity of paper insulation caused by an increase in moisture were analyzed. A linear equation, describing the changes in thermal conductivity due to moisture, for various types of paper and impregnated, was developed. The results of measuring the thermal conductivity of paper insulation depending on the temperature are presented. The aim of the study is to develop an experimental database to better understand the heat transport inside transformers to assess aging and optimize their performance.

scholarly journals Streamer propagation in a non-uniform electric field under lightning impulse in short gaps insulated with natural ester and mineral oil

2016 ◽  
Vol 64 (1) ◽  
pp. 171-179 ◽  
Author(s):  
P. Rozga
Keyword(s):  
Light Emission ◽  
Experimental Studies ◽  
Mineral Oil ◽  
Uniform Electric Field ◽  
Light Pulses ◽  
Streamer Propagation ◽  
Lightning Impulse ◽  
Small Electrode ◽  
Acceleration Voltage ◽  
Natural Ester

Abstract This article describes the comparative experimental studies on streamer propagation in natural ester and mineral oil under a high voltage lightning impulse. These studies were concentrated around the small electrode gaps and the point-plane electrode arrangement. The spatial shapes of the developing streamers, light emission and propagation velocity were analyzed and compared between the two different dielectric liquids. In both of them two streamer propagation modes were registered during the studies performed. Propagation of slow 2nd mode streamers took place below the so-called acceleration voltage while fast 3rd mode streamers developed at acceleration voltage and above. Comparing the streamer shapes corresponding to a given voltage polarity, no visible differences were observed between the liquids tested. Concerning the light emission, higher frequencies of light pulses were registered however in the case of natural ester. The significant differences between both liquids were noticed in the value of the acceleration voltage estimated. In the case of positive polarity streamers started to develop in natural ester as a 3rd mode at lower value of testing voltage than in the case of mineral oil. For negative polarity, within the applied testing voltages, 3rd mode streamers appeared only in natural ester. On this basis, the fundamental conclusion is that natural ester may have a lower ability of preventing the development of fast and energetic 3rd mode streamers, even at small electrode gaps.

scholarly journals The Influence of Nanoparticles’ Conductivity and Charging on Dielectric Properties of Ester Oil Based Nanofluid

Energies ◽  
2020 ◽  
Vol 13 (24) ◽  
pp. 6540
Author(s):  
Konstantinos N. Koutras ◽  
Ioannis A. Naxakis ◽  
Eleftheria C. Pyrgioti ◽  
Vasilios P. Charalampakos ◽  
Ioannis F. Gonos ◽  
...  
Keyword(s):  
Breakdown Voltage ◽  
Partial Discharge ◽  
Al2o3 Nanoparticles ◽  
Sic Nanoparticles ◽  
Base Oil ◽  
Dielectric Performance ◽  
Lightning Impulse ◽  
The Stability ◽  
Inception Voltage ◽  
Natural Ester

This study addresses the effect of nanoparticles’ conductivity and surface charge on the dielectric performance of insulating nanofluids. Dispersions of alumina and silicon carbide nanoparticles of similar size (~50 nm) and concentration (0.004% w/w) were prepared in natural ester oil. The stability of the dispersions was explored by dynamic light scattering. AC, positive and negative lightning impulse breakdown voltage, as well as partial discharge inception voltage of the nanofluid samples were measured and compared with the respective properties of the base oil. The obtained results indicate that the addition of SiC nanoparticles can lead to an increase in AC breakdown voltage and also enhance the resistance of the liquid to the appearance of partial discharge. On the other hand, the induction of positive charge from the Al2O3 nanoparticles could be the main factor leading to an improved positive Lightning Impulse Breakdown Voltage and worse performance at negative polarity.

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