• 제목/요약/키워드: Electrical breakdown characteristics

검색결과 1,005건 처리시간 0.025초

Analysis on the electrical degradation characteristics of 2G HTS wires with respect to the electrical breakdown voltages

  • Kang, Jong O;Lee, Onyou;Mo, Young Kyu;Kim, Junil;Bang, Seungmin;Lee, Hongseok;Lee, Jae-Hun;Jang, Cheolyeong;Kang, Hyoungku
    • 한국초전도ㆍ저온공학회논문지
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    • 제17권3호
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    • pp.37-40
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    • 2015
  • Recently, the electrical insulation design for electrical apparatuses is important to cope with the tendency of high voltage. The degradation characteristics of a superconducting coil due to an electrical breakdown should be considered to design a high voltage superconducting coil. In this paper, the degradation characteristics of 2G high temperature superconducting (HTS) wires are studied with respect to electrical breakdown tests. To analyze the dependency of the degradation characteristics of 2G HTS wires, the electrical breakdown tests are performed with AC(alternating current) and DC(direct current) voltage. All tests are performed by applying various magnitudes of AC and DC breakdown voltages. To verify the degradation characteristics of 2G HTS wires, the tests are performed with various 2G HTS wires with respect to stabilizer materials. The degradation characteristics of 2G HTS wires, such as Ic(critical current) and index number are measured by performing electrical breakdown tests. It is found that the characteristics such as Ic and index number can be degraded by an electrical breakdown. Moreover, it is concluded that the degradation characteristics of 2G HTS wires are affected by the stabilizer material and applied voltages. The cross-sectional view of 2G HTS wires is observed by using a scanning electron microscope (SEM). As results, it is found that the degradation characteristics of 2G HTS wires are concerned with hardness and electrical conductivity of stabilizer layers.

Quench에 의해 유도되는 액체 $N_2$의 절연파괴 특성 (Breakdown Characteristics of Liquid Nitrogen Induced by Quench)

  • 김영석;정종만;곽민환;정순용;김상현
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제48권1호
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    • pp.23-28
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    • 1999
  • Electrical breakdown characteristics of liquid nitrogen($LN_2$) used as both coolant and insulator for high $T_c$ superconductor system are very important. This paper presents dynamic breakdown characteristics fo $LN_2$ by quench phenomena of thermal bubble under high electric field. Experimental results revealed dynamic breakdown voltage fell down drastically compared with the static breakdown voltage without the quench. Because of increasing heat power, bubble size becomes big and breakdown voltage decreases. The breakdown voltage mechanism of $LN_2$ depends on thermal bubble effect. In the Electrode arrangement, electrical breakdown voltage of horizontal arrangement appears lower than that of vertical arrangement. Also, we observed the behavior of thermal bubbles in $LN_2$ which were generated after quench using camera.

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액체 $N_2$의 동적 절연파괴 특성 (Dynamic Electrical Breakdown Characteristics of Liquid Nitrogen)

  • 김영석;정종만;곽민환;백승명;장현만;김상현
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 1998년도 춘계학술대회 논문집
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    • pp.359-362
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    • 1998
  • Electrical breakdown characteristics of liquid nitrogen(LNd used as both coolant and insulator for high $T_c$ superconductor system is very important. This paper presents dynamic breakdown characteristics of liquid nitrogen by quench penomena of thermal bubble under high electric field. As the result, the breakdown mechanism of $LN_2$ depends on thermal bubble effect. The breakdown voltage decreases slightly with increasing heating. In the Electrode arrangement, electrical breakdown voltage of horizontal arrangement appears lower than that of vertical arrangement.

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Degradation characteristics of 2G HTS tapes with respect to an electrical breakdown

  • Kang, Jong O;Lee, Onyou;Mo, Young Kyu;Kim, Junil;Bang, Seungmin;Lee, Hongseok;Lee, Jae-Hun;Jang, Cheolyeong;Kang, Hyoungku
    • 한국초전도ㆍ저온공학회논문지
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    • 제17권1호
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    • pp.48-52
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    • 2015
  • The electrical insulation design for a superconducting coil system is important for developing high voltage superconducting apparatuses. Also, the degraded characteristics of superconducting tapes due to an electrical breakdown should be considered for superconducting coils design. In this study, the degradation characteristics of 2G high temperature superconducting (HTS) tapes were studied with respect to electrical breakdown tests. The degradation tests of 2G HTS tapes were performed with various stabilizer materials. The degradation characteristics of 2G HTS tapes such as critical current(Ic) and index number were observed by performing electrical breakdown tests. It was found that the characteristics such as Ic and index number can be degraded by an electrical breakdown. Moreover, it was concluded that the degradation characteristics of 2G HTS tapes were affected by a stabilizer material and applied breakdown voltage. The cross sectional view of 2G HTS tapes was observed by using a scanning electron microscope (SEM). As results, it is found that the degradation characteristics of 2G HTS tapes are concerned with hardness and electrical resistivity of stabilizer layers.

극저온 액체의 동적 절연파괴 특성 (Dynamic Electrical Breakdown Characteristics of Cryogenic Liquid)

  • 김상현;김현희;김영석;정종만;정순용
    • 한국전기전자재료학회논문지
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    • 제11권4호
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    • pp.321-326
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    • 1998
  • Electrical breakdown characteristics of liquid nitrogen($LN_2$) taking into consideration for application of high $T_c$ superconductor is very important. Also $LN_2$ will be used as both coolant and insulator in superconducting generator. In this paper, we investigated ac breakdown characteristics of cryogenic nitrogen gas above a $LN_2$ for rod-to plane electrode configuration. As result the breakdown mechanism of $LN_2$is dependence on bubble effect. And breakdown voltage is a ratio on bubble s size but electrodes arrangement is to make no difference. The breakdown voltage decreases slightly with increasing flow velocity, it again decreases abruptly with increasing flow velocity. These results were interpreted as the within pressure of rod electrode and Maxwell force.

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Laser CVD절연막의 전기전도와 절연파괴특성 (The eletrical conduction and breakdown characteristics of thin films by Laser CVD)

  • 강희복;권봉제;김용우;김성진;성영권
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1991년도 하계학술대회 논문집
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    • pp.191-193
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    • 1991
  • In this paper, we introduce silicon dioxide films deposited by Laser CVD, and evaluate the breakdown characteristics of these films by TZDB(Time Zero Dieiectric Breakdown) and TDDB(Time Dependent Dielectric Breakdown) test, failure times against eletric field are examined and accelation factors ${\beta}$ are obtained, and also, long term reliability is described by examining TDDB under positive voltage bias, all the above results are compared with PECVD(Plasma Enhanced CVD) $SiO_2$ breakdown, data, as a result, it is shown that the breakdown characteristics of Laser CVD $SiO_2$ films is improved.

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장간유리애자 파손시 절연파괴 특성 (The Electrical Breakdown Characteristics of Broken Toughened Glass Stem Insulator)

  • 정종욱;정진수;김영석
    • 전기학회논문지
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    • 제57권8호
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    • pp.1398-1406
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    • 2008
  • This paper describes the electrical breakdown characteristics of broken toughened glass stem insulators by comparing with those of sound ones. The broken toughened glass stem insulators were taken from the electric railway field. According to the international standards, the sound and broken toughened glass stem insulators were tested in electrical strength. In the test, the power frequency voltage and the impulse voltage with a standard waveform were applied to the insulators. The power frequency voltage tests were carried out under both dry and wet condition and the impulse voltage tests under only dry condition. The acquired results were compared one another and discussed in electrical breakdown characteristic by analyzing the flashover progress pictures. As a result, the electrical strength of the broken toughened glass insulators was acquired and the processes of the surface breakdown on the toughened glass insulators were confirmed.

고온초전도 기기응용을 위한 모의 \ulcorner치 환경에서 액체질소의 절연파괴 특성 (Electrical Breakdown Characteristics of LN2 under Simulated Quenching Conditions for Application of HTS Apparatus)

  • 백승명;정종만;김상현
    • 한국전기전자재료학회논문지
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    • 제15권11호
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    • pp.985-990
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    • 2002
  • The electrical breakdown characteristics of liquid nitrogen(LN$\sub$2/) were studied under simulated quenching conditions for application of HTS apparatus. The experimental results for various quenching condition revealed that the breakdown voltage of LN$\sub$2/ with bubble flow velocity and gap spacing. In the case, breakdown voltage decreases gradually with the bubble velocity. When it is bubble velocity from 0 to 1 $\ell$ /min, breakdown voltage rapidly decreases but decreases from 2 $\ell$/min to 10 $\ell$/min slowly. The breakdown voltage for vertical electrode arrangement is higher than that for horizontal electrode arrangement. Also, it did a electric field and potential distribution interpreting at the liquid nitrogen when the bubble existed. The plots of equipotential lines for three cases are also shown.

진단용 X 선관 절연유의 전기적 특성 (Electrical Properties of Insulating Oils for Diagnostic X-ray Tube)

  • 김건중;이인성;백금문;김두호;김왕곤;홍진웅
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집 Vol.14 No.1
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    • pp.597-600
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    • 2001
  • In order to investigate the electrical properties of X-ray tube oils for insulating and cooling, the breakdown characteristics in temperature range of $20\sim100[^{\circ}C]$, that of AC breakdown in 0.5~2.5[mm] of gap length, we are made researches. The classification for the physical properties of oil for X-ray tube by FTIR and H-NMR experiments was confirmed to type of mineral oils. As for the dependance of breakdown characteristics due to electrode gap length, breakdown voltage was found nearly uniform by impurity effect according to the increase of gap. As a result the characteristics for AC breakdown, the dielectric strength was increased to $90[^{\circ}C]$ but decreased over $90[^{\circ}C]$ in the temperature range.

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합성절연유의 절연파괴 특성에 미치는 유동대전 억제제의 영향 (The Effect of Antistatic Agent for Streaming Electrification on the Breakdown Characteristics of Synthetic Fluids)

  • 송병기;이수원;신종열;신현택;홍진웅
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1997년도 하계학술대회 논문집 C
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    • pp.1414-1416
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    • 1997
  • The electrical breakdown characteristics of the synthetic fluids No.2 of KS class VII used for insulating and cooling the materials for the ignition coil are studied. Also, Benzotriazole(BTA) as the streaming electrification suppressant additive is added to the oil, and the change of electrical properties due to different BTA concentration is investigated. To investigate the electrical characteristics, the breakdown strength of each specimen by an experiment for AC breakdown are analyzed. The breakdown strength of specimen by adding BTA is higher than virgin specimen in low e region, but lower than that in high region because of melting BTA. It is considered that the effective content of BTA as charge suppressant additive is about 10[ppm] from the results of AC breakdown.

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