• 제목/요약/키워드: Flashover Characteristics

검색결과 174건 처리시간 0.028초

액체질소 중에서의 연면방전 특성 (Characteristics of Surface flashover in LN2)

  • 정종만;백승명;김상현
    • 한국전기전자재료학회논문지
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    • 제16권1호
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    • pp.70-76
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    • 2003
  • For the development of superconducting power apparatus, it is necessary to establish the dielectric technology in coolant like L$N_2$. Therefore in this paper we conducted experiment of surface flashover that could occur in the windings of HTS transformer which will be developed in the pancake coil type. First, we distinguished two types of surface flashover by electrode alignment, such as parallel and vertical, and then compared with each characteristics of surface flashover. The flashover voltage was more affected by thickness of spacer than by surface length when the thickness of spacer is over 1 mm. And the surface flashover with metallic particle attached on the spacer was tested, it was affected by the particle position. The more close to the electrodes, the worse the characteristics. Also the experiment was conducted when the electrode was immersed in liquid nitrogen(L$N_2$) partially. The surface flashover characteristics of spacer was, when immersed partially in 50%, rapidly decreased.

대기중 연소화염에 의한 교류 플래시오버전압의 저하 특성 (Reduction Characteristics of AC Flashover Voltage by Combustion Flames under Atmospheric Conditions)

  • 김인식
    • 한국전기전자재료학회논문지
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    • 제14권12호
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    • pp.1041-1047
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    • 2001
  • In this paper, reduction characteristics of the ac flashover voltage in the horizontal air gap of sphere-sphere/needle-needle electrode system were investigated when the combustion flame was present near the high-voltage electrodes. The voltage and current waveforms were measured, when the flashover is occurred, in order to examine the flashover polarity by flame. The reduction characteristics of ac flashover voltage were discussed with the thermal ionization process, the relative air density and the deflection phenomena in the shape of flames that changed by the corona wind and coulomb\`s force. As the results of an experimental investigation, It was found that the reduction of flashover voltages in sphere-sphere system, in comparison with the no-flame case, are 79.9 [%] for k=0, 82.9 [%] for k=0.5, 87.5 [%] for k=1.0, 85.0 [%] for h=0 [cm], 40.8 [%] for h=5 [cm] and 28.2 [%] for h=9 [cm] when ac voltage is applied.

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N2/O2 혼합가스 중 적층된 고체유전체에 대한 연면방전의 메커니즘과 특성 (Mechanism and Characteristics of the Surface Flashover on the Laminated Solid Dielectric in N2/O2 Mixture Gas)

  • 임동영;최은혁;최상태;배성우;이광식;최병주
    • 조명전기설비학회논문지
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    • 제29권8호
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    • pp.32-39
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    • 2015
  • This paper presents the surface flashover mechanism of a laminated solid dielectric and describes the surface flashover characteristics with the inherent capacitance of the laminated solid dielectric in a $N_2/O_2$ mixture gas (8:2) under an quasi uniform field. It was found that the electron emission at a cathode and the high-local electric field region around an anode were important factors to reasonably describe the surface flashover mechanism. The surface flashover voltage by the mechanism decreased with the inherent capacitance increase of the laminated solid dielectric. In addition to the surface flashover mechanism and its characteristics, the surface flashover voltage equations as a function of the inherent capacitance were derived by considering a gas pressure used in future eco-friendly GIS and the factors influencing the surface flashover.

공간연면 직렬간극의 섬락방전특성에 관한 연구 (A study on the flash over characteristics in space and surface series air gaps)

  • 김원섭
    • 전기의세계
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    • 제25권1호
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    • pp.87-94
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    • 1976
  • The characteristic of flashover electric discharge has been brought to light in this paper for the situation in which the space and creeping gaps are laid out in series. The result of this study has disclosed the facts that the over all flashover characteristics have three kind of features such as unilateral increase after increase, and increase after decrease in compliance with varied layout method and relative magnitude of gap length, and accordingly there exist a ratio among the magnitudes of gap length and a proper layort method through which the over all flashover voltage reaches the highest. Also involved with this study is the theoretic analysis of flashover characteristics even in the case of creeping electric discharge from hand tip of the gauge, where the over all value of flashover voltage can be estimated from the peculiar value of flashover voltage and flicker voltage for the space and creeping gap within the extent of 5% error.

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연소화염 존재 시 수직형 모델 전력선의 섬락 특성 (Flashover Characteristics of Vertical-type Model Power Line in the Presence of Combustion Flame)

  • 김인식
    • 조명전기설비학회논문지
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    • 제23권5호
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    • pp.58-65
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    • 2009
  • 전력선이 통과하는 지역에서 발생된 산불은 계통 섬락사고의 원인이 되고 있다. 본 연구에서는 연소화염에 의한 전력선의 절연내력 저하특성을 알아보기 위해 직류 및 교류 전압 인가 시, 연소화염과 고전압 도체의 수평거리(s)를 변화시켰을 때, 수직형 모델 전력선에 대한 섬락특성을 조사하였다. 실험 결과, 수평거리(s)가 작은 범위에서는 화염이 모델선로의 섬락전압을 크게 감소시킬 수 있는 것으로 나타났다. 이러한 섬락전압의 저하요인을 해석하기 위해 화염주변의 상대공기밀도가 고려되었으며, 화염이 존재하는 경우에는 그 영향이 매우 크게 나타남을 알 수 있었다.

평단봉대평판 전극배치에서 평판 전극에 화염이 존재할 때 공기의 섬락전압 특성 (Flashover Characteristics of Air in the Arrangement of Cylinder-Shaped Rod and Plane Electrode in Case of Flame on the Plane Electrode)

  • 김인식
    • 조명전기설비학회논문지
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    • 제26권4호
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    • pp.82-87
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    • 2012
  • In this paper, flashover characteristics of air in the vertical arrangement of cylinder-shaped rod and plane gap in the case of combustion flame on the plane electrode were examined under the application of a.c. and d.c. high-voltages. In order to investigate the effect of propane flame on the flashover characteristics of air, flashover voltages in accordance with the variation of the gap length and the horizontal distance between the flame and the high-voltage rod electrode were measured. As the result of the experiment, flashover voltages in the presence of the flame were substantially lowered than those in the absence of flame, and the polarity effects with the d.c. voltages on appeared owing to the flame. Flashover voltages of air were increased in the proportion of the gap length and the horizontal distance in the case of both a.c. and d.c. voltages, but the flame was extinguished by such corona wind that was produced from the rod electrode when the gap length and the horizontal distance reached to a certain degree.

인공오손에 따른 배전기자재의 건조 및 습윤 섬락에 관한 연구 (The Study on the Dry and Wet Flashover Voltages of the Artificially Salt Contaminated Distribution Facilities)

  • 김찬영;김동명;권태호
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.487-488
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    • 2008
  • The dry and wet flashover characteristics on the contaminated distribution facilities was investigated. The test were carried out on the suspension insulator, line post insulator, lightning arrester, cut off switch, etc. In the dry state, the flashover voltages of facilities contaminated with B, C, D classes are similar to the non-contaminated ones. However, in the wet state, the flashover voltages of facilities contaminated with B, C, D classes are decreased. The flashover voltages of some few facilities show under the standard value. This results indicate that the high humidity may cause the flashover on distribution facilities.

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ESS 안전성 개선을 위한 결로 운전 조건 고려 고체절연물 연면 절연파괴특성 분석 (Analysis on Solid Insulator Flashover Characteristics on Moisture Contamination for Electrical Insulation Improvement of ESS)

  • 김진태;이승용;김지영;석복렬
    • KEPCO Journal on Electric Power and Energy
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    • 제7권2호
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    • pp.317-321
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    • 2021
  • As the large-scale renewable energy power plant increases, the high-capacity and compact Energy Storage System (ESS) is required. However, this trend could reduce the insulation reliability of ESS. In this study, the surface flashover characteristics for four types of solid insulators are investigated in the uniform electric field with AC and Lightning Impulse (LI) voltage waveforms under various contamination levels. In addtion, insulator surfaces are compared based on the contact angle before and after surface flashover. The experimental results show that AC flashover voltage is dependent on the materials and the contamination level, but LI flashover voltage is only associated with the contamination level. Especially, AC flashover voltage of PC (PolyCarbonate) is higher than that of other insulators, which is associated with the unique and sequential creepage discharge propagation pattern of PC. The localized discharges on the surface of PC form corresponding tracking points. Then, the interconnected trackings result in the complete flashover. This flashover patterns degrade the surface of PC much more than that of epoxy and Bulk Molding Compoud (BMC). Thus, the contact angle of PC is significantly reduced compared to that of other insulators. The increased hydrophilicity in the surface of PC enhances the insulator surface conductivity.

진공 중에서 알루미나의 플래쉬오버 (Pre-Flashover of Alumina in Vacuum)

  • 최용성;이경섭
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2008년도 하계학술대회 논문집 Vol.9
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    • pp.375-376
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    • 2008
  • The flashover of insulators in vacuum is the main factor to limit the performance of insulation in vacuum insulation system. It is believed that the pre-flashover phenomena would play a very important role in the procedure of the flashover in the interface between the insulators and vacuum. This paper is mainly concerned on the pre-flashover phenomena of Alumina insulators in vacuum. There are 24 different types of alumina insulators were tested with a 0.7/4 ${\mu}s$ pulsed voltage under a $1\times10^{-4}$Pa vacuum. The observed pre-flashover phenomena were classified and the pre-flashover characteristics were concluded. It is useful to study further on the flashover mechanism in vacuum.

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연면섬락특성의 한 개선방법에 대한 실험적 고찰 (Experimental consideration on some method of improving surface flashover discharge characteristics)

  • 정성계;이계호;김원섭
    • 전기의세계
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    • 제18권2호
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    • pp.21-25
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    • 1969
  • This paper shows experimentally the characteristics of raising up the flashover voltage in supension insulators or bushing according to the theoretical results which was gotten by previous study. It was shown theoretically that, if some conducting metallic barriers are inserted into the flashover discharge path, the flashover voltage is found to be increased considerably. In order to verify this theoretical results, some basic experimental study was done, and the results was found to be more or less satisfactory except some problems which must be considered in future study.

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