Streamer propagation in small gaps of synthetic ester and mineral oil under lightning impulse

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.

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Positive streamer propagation in small gap of synthetic ester under lightning impulse

2014 IEEE 18th International Conference on Dielectric Liquids (ICDL) ◽

10.1109/icdl.2014.6893076 ◽

2014 ◽

Cited By ~ 1

Author(s):

Pawel Rozga

Keyword(s):

Synthetic Ester ◽

Streamer Propagation ◽

Lightning Impulse ◽

Positive Streamer

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Comparison of dielectric properties of olive oil, mineral oil, and other natural and synthetic ester liquids under AC and lightning impulse stresses

IEEE Transactions on Dielectrics and Electrical Insulation ◽

10.1109/tdei.2018.007218 ◽

2018 ◽

Vol 25 (5) ◽

pp. 1822-1830 ◽

Cited By ~ 13

Author(s):

Abderrahim Reffas ◽

Hocine Moulai ◽

Abderrahmane Beroual

Keyword(s):

Dielectric Properties ◽

Olive Oil ◽

Mineral Oil ◽

Synthetic Ester ◽

Lightning Impulse ◽

Natural And Synthetic

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Streamer Propagation and Breakdown in a Very Small Point-Insulating Plate Gap in Mineral Oil and Ester Liquids at Positive Lightning Impulse Voltage

Energies ◽

10.3390/en9060467 ◽

2016 ◽

Vol 9 (6) ◽

pp. 467 ◽

Cited By ~ 14

Author(s):

Pawel Rozga

Keyword(s):

Mineral Oil ◽

Impulse Voltage ◽

Streamer Propagation ◽

Lightning Impulse ◽

Small Point

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

IET Science Measurement & Technology ◽

10.1049/iet-smt.2014.0313 ◽

2016 ◽

Vol 10 (1) ◽

pp. 50-57 ◽

Cited By ~ 17

Author(s):

Pawel Rozga ◽

Marcin Stanek

Keyword(s):

Mineral Oil ◽

Synthetic Ester ◽

Lightning Impulse ◽

Inception Voltage ◽

Natural Ester

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Influence of Molecule Structure on Lightning Impulse Breakdown of Ester Liquids

Energies ◽

10.3390/en14041061 ◽

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.

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Electrophysical properties of mixtures of mineral oil and synthetic ester dielectric liquid

Safety and Reliability of Power Industry ◽

10.24223/1999-5555-2021-14-2-132-141 ◽

2021 ◽

Vol 14 (2) ◽

pp. 132-141

Author(s):

M. N. Lyutikova ◽

S. M. Korobeynikov ◽

A. A. Konovalov

Keyword(s):

Dielectric Loss ◽

Breakdown Voltage ◽

Loss Tangent ◽

Dielectric Loss Tangent ◽

Kinematic Viscosity ◽

Mineral Oil ◽

Flash Point ◽

Power Transformers ◽

Synthetic Ester ◽

Insulating Properties

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.

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