• 제목/요약/키워드: breakdown strength

검색결과 523건 처리시간 0.023초

배전용 몰드변압기 적용을 위한 EMNC의 교류절연파괴특성 연구 (AC Insulation Breakdown Properties of the EMNC to Application of Distribution Molded Transformer)

  • 박재준
    • 전기학회논문지
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    • 제62권5호
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    • pp.649-656
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    • 2013
  • A conventional epoxy-microsilica composite (EMC) and an epoxy-microsilica-nanosilicate composite (EMNC) were prepared in order to apply them to mold-type transformers, current transformers (CT) and potential transformers (PT). Nanosilicate was exfoliated in a epoxy resin using our electric field dispersion process and AC insulation breakdown strength at $30{\sim}150^{\circ}C$, glass transition temperature and viscoelasticity were studied. AC insulation breakdown strength of EMNC was higher than that of EMC and that value of EMNC was far higher at high temperature. Glass transition temperature and viscoelasticity property of EMNC was higher than those of EMC at high temperature. These results was due to the even dispersion of nanosilicates among the nanosilicas, which could be observed using transmission electron microscopy (TEM). That is, the nanosilicates interrupt the electron transfer and restrict the mobility of the epoxy chains.

XLPE/EPDM laminates의 계면현상 (Interfacial phenomena of XLPE/EPDM laminates)

  • 남진호;서광석;김지환;고광철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1998년도 추계학술대회 논문집
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    • pp.211-214
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    • 1998
  • DC breakdown characteristics and formation of space charge at the interfaces of crosslinked polyethylene (XLPE) /ethylene propylene diene terpolymer (EPDM) laminates were studied. Effects of silicone grease and some chemicals such as crosslinking coagent on the interfacial charge were also studied. Interfacial charge develops at the interface of XLPE/EPDM laminates, which changes depending on heat treatment conditions and types of chemicals coated at the interface. Some chemicals such as maleic anhydride reduce the accumulation of interfacial charge in the XLPE/EPDM laminates. Breakdown strength of EPDM/XLPE laminate through the interface was highest when silicone oil was pasted in the interfaces. Interfacial breakdown strength decreased with the increase of MAH content.

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Poly (Vinylidene Fluoride) 박막의 절연파괴와 온도의존성 (Dependence of Dielectric breakdown of Thin Poly (Vinylidene Fluoride) Film on Temperature)

  • 김동욱;박대희
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1989년도 하계종합학술대회 논문집
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    • pp.380-382
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    • 1989
  • Dielectric breakdown strength (Eb) of thin Poly(Vinylidene Fluoride ; PVDF) film is studied in the temperature range between 4.2 K and 400 K. The results of this study can be summerized as follows. 1) Temperature dependence of dielectric breakdown strength (Eb) can be devided into high and low temperature regions. The critical temperature (Tc) at which two regions are devided depends on applied voltage. 2) Dielectric breakdown strength (Eb) by pulse voltage is higher than that by DC voltage. Especially this difference is remarkable at low temperature.

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다양한 첨가제에 따른 가교폴리에틸렌의 절연특성 분석 (A study on insulation Characteristics of XLPE by various additives)

  • 송상민;김규식;손원근;류부형;박수길
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 춘계학술대회 논문집 유기절연재료 전자세라믹 방전플라즈마 연구회
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    • pp.193-196
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    • 2001
  • XLPE is occasionally happened to deteriorate cable insulation characteristics. It is happened to do a breakdown state by the degradation of electrical characteristic and electrical breakdown strength. I prepared TR-XLPE (Tree-Retardant XLPE) as adding various additives to prevent its states. Various additives are treeing retardants, anti-oxidants. Treeing retardants three kinds of aromatic compounds as adding each additive. Anti-oxidants use quinone compound and cresol compound as adding each additive. In order to observe each electrical characteristics, I measured breakdown strength, relative dielectric constant$({\varepsilon}_r)$, dielectric loss tangent$(tan{\delta})$. TR-XLPE specimens as adding treeing retardants and anti-oxidants enhance breakdown strength, ${\varepsilon}_r$, $tan{\delta}$ than pure XLPE.

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기계적 응력상태에서 절연지 및 케이블의 전기절연 특성 (The Characteristics of Electrical Breakdown of Dielectric Paper and Cable under mechanical stress)

  • 김영석;곽동순;김해종;김상현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2003년도 제5회 영호남 학술대회 논문집
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    • pp.3-6
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    • 2003
  • The electrical and mechanical properties of dielectric paper and cable at cryogenic temperature have been investigated to optimum insulating design of high-Tc superconducting(HTS) cable. From the results, Tensile strength of PPLP in liquid nitrogen was high more than that of air, but tensile strain could know that decrease sharply. According as tensile strength increases, the breakdown stress of PPLP in liquid nitrogen was decreased because PPLP was degradated. According as bending radius multiple is decrese, breakdown voltage decreased sharply. And bending radius multiple is thought that more than about 25 is suitable.

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에폭시/고무 거시계면에서 장시간 절연파괴전압에 대한 연구 (Study on the Long Time Breakdown Voltage in the Macro Interface between Epoxy and Rubber)

  • 박우현;이기식
    • 한국전기전자재료학회논문지
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    • 제15권11호
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    • pp.1003-1008
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    • 2002
  • In this paper, the estimation of lifetime with the various conditions of the interface between toughened epoxy and rubber which are consisting materials of underground power delivery system has been studied. After the measurement of the short time AC interfacial breakdown strength on macro interfaces at room temperature, the breakdown time at several voltages were measured under the constant voltages lower than the short time breakdown voltage. The long time breakdown voltage was calculated by using Inverse Power Law. Two types of interfaces was studied. One was the interface between toughened epoxy and EPDM(Ethylene Prorylene Diene Terpolymer). The other was the interface between toughened epoxy and silicon rubber. Interfacial pressure and roughness of interfaces was determined through the characteristic of short time AC interfacial breakdown strength. Oil condition was no oiled, low viscosity oiled and high viscosity oiled. High viscosity oiled interface between Toughened epoxy and silicon rubber had the best lifetime exponent, 20.69. and the breakdown voltage of this interface after 30 years was evaluated 19.27㎸.

강유전체에서의 전계분포 및 절연파괴 (Dielectric Breakdown and Electric Stress Distribution in Ferroelectrics)

  • 신병철;김호기
    • 한국세라믹학회지
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    • 제24권4호
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    • pp.392-396
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    • 1987
  • Pure barium titanate was sintered at $1340^{\circ}C$ for 2, 4, 8, 16 hr to control their grain size. The measurements of breakdown strength and partial discharge characteristics were performed under rising AC voltage(60Hz). With increase of sintering time, the average grain size was increased and breakdown strength was slightly decreased. Partial discharge in pores was observed under high voltage, and a model of dielectric break down in barium titanate ceramics is proposed.

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XLPE/EPOM 계면의 전기적 특성 (Electrical Characteristics on the Interface between XLPE/EPDM)

  • 한성구;조정형;이창종;김종석;서광석;박대희;한상옥
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1996년도 춘계학술대회 논문집
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    • pp.235-238
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    • 1996
  • In this paper, We intended to evaluate the characteristics of XLPE/EPDM interface which exists in the cable joint. The fault was mainly occurred in this interface. Thus we looked into the electrical characteristics through the conduction current and the breakdown test. Through from the experiment, we obtained the result that the conduction current in this interface flowed less than other dielectric materials, that the breakdown strength was higher and that the pressure dependance ㅐf the breakdown strength was higher.

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XLPE/EPDM laminate의 절연파괴특성 (Interfacial Breakdown characteristics in XLPE/EPDM Laminate)

  • 남진호;서광석
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1999년도 추계학술대회 논문집
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    • pp.495-497
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    • 1999
  • In order to determine what influences the interfacial breakdown in EPDM/XLPE laminates, We made the breakdown test ceil and this was pressure controllable breakdown test cell. We make the needle electrode (tip radius: about 10 micrometer) using electrochemical method. We studied the interfacial silicone oil was higher than that with silicone grease. As a function of heat treatment time in a vacuum, interfacial breakdown strength increased much in XLPE/EPDM laminates pasted with silicone grease but increased a little in that with silicone oil.

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여러 종류의 에폭시/이종무기물 혼합 콤포지트의 전기적 교류 절연파괴 특성 (Electrical AC Insulation Breakdown Characteristics of Various Epoxy / Heterogeneous Inorganic Mixed Composite)

  • 박재준
    • 전기학회논문지
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    • 제67권11호
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    • pp.1463-1470
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    • 2018
  • In this study, 20 types of samples were prepared by mixing different kinds of inorganic materials to develop insulation materials for epoxy - based GIS substation equipment used under high voltage environmentally friendly insulation gas. One of the electrical characteristics, AC insulation breakdown experiment was performed. As mixing ratio of mixed heterogeneous inorganic materials, the dielectric breakdown strength was increased with increasing filler ratio of micro silica, micro silica : micro Alumina, 1:9, 3:7, 5:5, 7:3, 9:1, and decreased as the filling amount of micro alumina increased. The AC insulation breakdown characteristics were the best when the composition ratio was 9:1. The higher the content of silica, the better the interfacial properties, and the larger the alumina content ratio, the worse the interfacial properties.