• Title/Summary/Keyword: Treeing Phenomena

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Effect of Electric Field Frequency on the AC Electrical Treeing Phenomena in an Epoxy/Layered Silicate Nanocomposite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.5
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    • pp.278-281
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    • 2013
  • The effects of electric field frequency on the AC electrical treeing phenomena in an epoxy/layered silicate (1.5 wt%) were investigated in a needle-plate electrode arrangement. A layered silicate was exfoliated in an epoxy-base resin with AC electric field apparatus. To measure the treeing initiation and propagation- and the breakdown rate, a constant alternating current (AC) of 10 kV with three different electric field frequencies (60, 500, and 1,000 Hz) was applied to the specimen in the needle-plate electrode specimen in an insulating oil bath at $130^{\circ}C$. At 60 Hz, the treeing initiation time was 12 min, the propagation rate was $0.24{\times}10^{-3}$ mm/min, and the morphology was a dense branch type. As the electric field frequency increased, the treeing initiation time decreased and the propagation rate increased. At 1,000 Hz, the treeing initiation time was 5 min, the propagation rate was $0.30{\times}10^{-3}$ mm/min, and the morphology was a dense bush type.

Treeing Phenomena in the Home-made Solid Organic Insulating Materials (국산유기절연재료의 Treeing현상)

  • 성영권;이헌용;이계호;유기한
    • 전기의세계
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    • v.26 no.2
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    • pp.57-65
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    • 1977
  • In roder to investigate the influence of treeing on electric breakdown of solid organic insulator the initiation and growing mechanism of tree itself, and the correlation between corona discharge and treeing phenomena in solid orgainc insulating materials, several experiments were carried out by means of needle test on polymethyl-methacrylate. The obtained results showed that the existence of voids in specimen had important effects on initiation voltage of trees and, when the direct voltage was applied, the initiation voltage of trees increased by space charge effect. And also the stagnation phenomena due to the transfer of vacancy cluster or polymekr cage in specimen might beconsidered in process of growth of trees, and corona discharge seemed to be the pre-phenomena of treeing because trees were normally initiated by internal discharge in voids.

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Effect of Electric Field Frequency on the AC Electrical Treeing Phenomena in an Epoxy/Reactive Diluent/Layered Silicate Nanocomposite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.15 no.2
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    • pp.87-90
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    • 2014
  • The effects of electric field frequency on the ac electrical treeing phenomena in an epoxy/reactive diluent/layered silicate (1.5 wt%) were carried out, in needle-plate electrode arrangement. A layered silicate was exfoliated in an epoxy base resin, by using our ac electric field apparatus. To measure the treeing propagation rate, constant alternating current (AC) of 10 kV with three different electric field frequencies (60, 500 and 1,000 Hz) was applied to the specimen, in needle-plate electrode arrangement, at $30^{\circ}C$ of insulating oil bath. As the electric field frequency increased, the treeing propagation rate increased. At 500 Hz, the treeing propagation rate of the epoxy/PG/nanosilicate system was $0.41{\times}10^{-3}$ mm/min, which was 3.4 times slower than that of the epoxy/PG system. The electrical treeing morphology was dense bush type at 60 Hz; however, as the frequency increased, the bush type was changed to branch type, having few branches, with very slow propagation rate.

AC Electrical Treeing Phenomena in an Epoxy System with Low-chlorine BDGE at Various Electric Field Frequencies

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.6
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    • pp.324-328
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    • 2013
  • An alternating current (AC) electrical treeing phenomena in an epoxy system with low chlorine BDGE (1,4-butanediol diglycidyl ether) was studied in a needle-plate electrode arrangement. To measure the treeing propagation rate and breakdown time, a constant AC of 10 kV with three different electric field frequencies (60, 500, and 1,000 Hz) was applied to the needle-plate electrode specimen at $130^{\circ}C$ in aninsulating oil bath. The treeing propagation rate of the DGEBA/high-chlorine BDGE system was higher than that of the DGEBA/low-chlorine BDGE system and the breakdown time of the system with high-chlorine BDGE was lower than that of the system with low-chlorine BDGE. These results implied that chlorine had a negative effect on the electrical insulation property of the epoxy system. As the electric field frequency increased, the treeing propagation rate increased and the breakdown time decreased.

A Study on the Breakdown Characteristics in Cross-linked Polyethylene by Treeing Effect (가교폴리에틸렌의 내부방전효과에 의한 절연파괴특성)

  • 곽영순;이양성;조정수
    • 전기의세계
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    • v.27 no.6
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    • pp.76-83
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    • 1978
  • This paper reveals the results of fundamental experiments with the breakdown strength- and treeing phenomena, by A.C voltage and impulse voltage, of cross-linked polyethylene insulator, respectively compared in each case of the various specimens; nonvoid, air void, water void, oil void and oil impregnated one, all articially made. In this research, the V-t and V-n characteristics are investigated by means of the Weibull distribution and are analysed the characteristics of fatigue breakdown caused by the A.C and impulse voltage. Based on numerous tests, treeing effect and treeing breakdown mechanism is investigated through microscopic photographs taken to clarify the shapes of each tree and treeing breakdown phenomena.

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Effect of Ambient Temperature on the AC Electrical Treeing Phenomena in an Epoxy/Layered Silicate Nanocomposite

  • Park, Jae-Jun
    • Transactions on Electrical and Electronic Materials
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    • v.14 no.4
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    • pp.221-224
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    • 2013
  • Effects of ambient temperature on the ac electrical treeing and breakdown behaviors in an epoxy/layered silicate (1 wt%) were carried out in needle-plate electrode geometry. A layered silicate was exfoliated in an epoxy base resin,, using our ac electric field apparatus. To measure the treeing initiation and propagation, and the breakdown rate, constant alternating current (ac) of 10 kV (60 Hz) was applied to the specimen in a needle-plate electrode arrangement, at $30^{\circ}C$, $90^{\circ}C$ or $130^{\circ}C$ of insulating oil bath. At $30^{\circ}C$, the treeing initiation time and the breakdown time in the epoxy/layered silicate (1 wt%) system were 1.4 times higher than those of the neat epoxy resin. At $90^{\circ}C$ (lower than Tg), electrical treeing was initiated in 55 min, and propagated until 1,390 min at the speed of $0.35{\times}10^{-3}mm/min$, which was 4.4 times higher than that at $30^{\circ}C$; however, there was almost no further treeing propagation after 1,390 min. At $130^{\circ}C$ (higher than Tg), electrical treeing was initiated in 44 min, and propagated until 2,000 min at the speed of $0.96{\times}10^{-3}mm/min$. Typical branch type electrical treeing was obtained from the neat epoxy and epoxy/layered silicate at $30^{\circ}C$, while bush type treeing was observed out from the needle tip at $90^{\circ}C$ and $130^{\circ}C$.

An Analysis on Treeing in XLPE by means of Image Processing (화상처리에 의한 XLPE의 트리잉 해석)

  • 이재봉;임장섭;정우성;김태성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1994.11a
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    • pp.122-128
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    • 1994
  • Studies on treeing phenomena have depended on the visual measurement using optical microscope. In the visual measurement, it is difficult to analyze the treeing in real time because voltages are applied discontinuously and impossible to calculate the deterioated area by treeing. Only tree type and length are studied. In this paper, image processing is introduced and voltages are applied continuously. The tree length and area are calculated in real time from tree inception to breakdown. Growing characteristics about tree types are compared for the normalized breakdown time.

A Study on Long-time Electrical Treeing Deterioration Properties According to High Frequency Voltage of Epoxy Resin (에폭시수지의 고전압 전원주파수 변화에 따른 장시간 전기적 트리잉 열화 특성연구)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.11
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    • pp.1571-1577
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    • 2013
  • Electrical tree structure is one of the most important influencing factors for electrical treeing characteristics in polymers. In this paper, we focused on the structure characteristics of electrical treeing in epoxy resins (original) insulation under different high-frequency voltages (60, 500, 1000Hz). Effects of voltage frequency on the ac electrical treeing phenomena in an epoxy resins were carried out in needle-plate electrode arrangement. To measure the treeing initiation and propagation, and the breakdown rate, constant AC of 10 kV with three different voltage frequencies (60, 500 and 1,000 Hz) was applied to the specimen in needle-plate electrode specimen at $30^{\circ}C$ of insulating oil bath. At 60 Hz, the treeing initiation time was 360 min and the propagation rate was $6.85{\times}10^{-4}mm/min$, and the morphology was dense branch type. As the voltage frequency increased, the treeing initiation time decreased and the propagation rate increased. At 1,000 Hz, the treeing initiation time was 0 min and the propagation rate was $7.81{\times}10^{-2}mm/min$, and the morphology was dense bush type.

Electrical Treeing Deterioration and Dielectric Breakdown Phenomena in Polymeric Insulator (고분자 절연재료에서 전기트리 열화 및 절연파괴 현상)

  • Cho, Yeong-Sin;Kim, Sang-Uk
    • Korean Journal of Materials Research
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    • v.9 no.4
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    • pp.398-403
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    • 1999
  • Studies on the electrical treeing deterioration and dielectric breakdown phenomena in the polymeric insulator of polyethylene and epoxy resin were carried out. Block type samples with needle-plane electrode geometry were electrically stressed and the tree pattern from the needle tip was observed. In LDPE the density of electrical tree was very high and its pattern was bush type. For the case of XLPE, branched tree was observed. As temperature and SN content increased, the dielectric breakdown voltage decreased and the treeing phenomena became more complicated. Fan type cracks were observed around the conducting tree path in the brittle DGEBA/MDA system.

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Characteristics of AC Treeing for Three Epoxy Resins for High Voltage Heavy Electric Machine Appliances (고전압 중전기기용 에폭시 수지 3종에 대한 교류트리잉 파괴특성)

  • Park, Jae-Jun
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.67 no.10
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    • pp.1322-1329
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    • 2018
  • In this paper, the reliability test of three kinds of epoxy resin for GIS Spacer, which is a high voltage based heavy electric machine, AC electrical treeing experiments were performed. Three types of epoxy resins, Araldite B41, CT 5531 CI and B46, have slight viscosity differences. An non-uniform electric field, E = 1149.4 kV/mm, as the needle to plate electrode, a power source with a frequency of 1 kHz was applied to the tree electrode for accelerated deterioration. The treeing phenomena of the three kinds of epoxy resin all initiated, propagated, and destroyed by the branch tree. Epoxy Resin B46 was 145 times longer than B41 and 53 times longer than CT 5531CI. I think that the choice of epoxy resin is very important in choosing high voltage heavy electric machine insulation materials.