• 제목/요약/키워드: Electrical breakdown voltage

검색결과 1,206건 처리시간 0.039초

A Study on the Insulation Characteristics for Stator Windings of IGBT PWM Inverter-Fed Induction Motors

  • Hwang, Don-Ha;Kang, Dong-Sik;Kim, Yong-Joo;Lim, Tae-Hoon;Bae Sung-Woo;Kim Dong-Hee;Ro Chae-Gyun
    • Journal of Power Electronics
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    • 제3권3호
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    • pp.159-166
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    • 2003
  • The winding insulation of low-voltage induction motors in adjustable-speed drive system with voltage-fed Inverters is substantially stressed due to the uneven voltage distribution and excessive voltage stress (dv/dt), which result in the premature insulation breakdown In this paper, the detailed insulation test results of 26 low-voltage induction motors are presented. Six different types of insulation techniques are applied to 26 motors. The insulation characteristics are analyzed with partial discharge, discharge inception voltage, AC current, and dissipation factor tests Also, insulation breakdown tests by high voltage pulses are performed, and the corresponding breakdown voltages obtained.

Characteristics of Insulation Diagnosis and Failure in Gas Turbine Generator Stator Windings

  • Kim, Hee-Dong
    • Journal of Electrical Engineering and Technology
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    • 제9권1호
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    • pp.280-285
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    • 2014
  • In order to evaluate the insulation deterioration in the stator windings of five gas turbine generators(137 MVA, 13.8 kV) which has been operated for more than 13 years, diagnostic test and AC dielectric breakdown test were performed at phases A, B and C. These tests included measurements of AC current, dissipation factor, partial discharge (PD) magnitude and capacitance. ${\Delta}I$ and ${\Delta}tan{\delta}$ in all three phases (A, B and C) of No. 1 generator stator windings showed that they were in good condition but PD magnitude indicated marginally serviceable and bad level to the insulation condition. Overall analysis of the results suggested that the generator stator windings were indicated serious insulation deterioration and patterns of the PD in all three phases were analyzed to be internal, slot and spark discharges. After the diagnostic test, an AC overvoltage test was performed by gradually increasing the voltage applied to the generator stator windings until electrical insulation failure occurred, in order to determine the breakdown voltage. The breakdown voltage at phases A, B and C of No. 1 generator stator windings failed at 28.0 kV, 17.9 kV, and 21.3 kV, respectively. The breakdown voltage was lower than that expected for good-quality windings (28.6 kV) in a 13.8kV class generator. In the AC dielectric breakdown and diagnostic tests, there was a strong correlation between the breakdown voltage and the voltage at which charging current increases abruptly ($P_{i1}$, $P_{i2}$).

유전체 장벽 방전(DBD) 씨드 캐리어를 이용한 저 전압 대기압 플라즈마 발생 (Low Voltage Atmospheric Plasma Generation using DBD Initiation Carrier Injection)

  • 황솔;박현호;김영민
    • 전기학회논문지
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    • 제67권1호
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    • pp.82-86
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    • 2018
  • Low voltage atmospheric plasma generation using DBD Initiation carrier injection is reported. DBD afterglow was used as initiation carriers prior to a primary discharge and a significant reduction in the breakdown voltage of atmospheric discharge was observed when sufficient initiation carriers were provided. Quantative correlation study between the breakdown voltage and the initiation carriers suggests that the atmospheric breakdown voltage reduces to only half of the breakdown voltage for Townsend regime. Also, use of DBD initiation carrier injection likely offers better device reliability by protecting electrodes with a dielectric layer and thus suppressing electrode wear.

An analysis of new IGBT(Insulator Gate Bipolar Transistor) structure having a additional recessedwith E-field shielding layer

  • 유승우;이한신;강이구;성만영
    • 전기전자학회논문지
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    • 제11권4호
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    • pp.247-251
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    • 2007
  • The recessed gate IGBT has a lower on-state voltage drop compared with the DMOS IGBT, because there is no JFET resistance. But because of the electric field concentration in the corner of the gate edge, the breakdown voltage decreases. This paper is about the new structure to effectively improve the Vce(sat) voltage without breakdown voltage drop in 1700V NPT type recessed gate IGBT with p floating shielding layer. For the fabrication of the recessed gate IGBT with p floating shielding layer, it is necessary to perform the only one implant step for the shielding layer. Analysis on the Breakdown voltage shows the improved values compared to the conventional recessed gate IGBT structures. The result shows the improvement on Breakdown voltage without worsening other characteristics of the device. The electrical characteristics were studied by MEDICI simulation results.

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유입변압기용 절연유의 절연파괴특성 (Electrical Breakdown Properties of Insulating Oils for oil-immersed transformer)

  • 이인성;신현택;이종필;이수원;홍진웅
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 추계학술대회 논문집
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    • pp.605-608
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    • 2001
  • With the intention of investigating the breakdown properties of oil-immersed transformer oils in temperature range of 20∼100[$^{\circ}C$], we are made researches AC breakdown in the gap of 500∼2,500[$\mu\textrm{m}$]. The classification for the physical properties of oil for oil-immersed transformer by FTH and $^1$H-NMR experiments was confirmed to type of mineral oils. As the dependance of breakdown properties due to electrode gap length variation, breakdown voltage was found increasing according to the increase of gap, while dielectric strength was decreasing. As a result the characteristics for AC breakdown, It goes to prove that the breakdown voltage was increased to 90[$^{\circ}C$] but decreased over 90[$^{\circ}C$] in the temperature range. Also, breakdown voltage was found increasing in the increase of gap and the rising of temperature according to Weibull distribution.

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식물성절연유의 유동속도와 온도에 따른 절연파괴전압 (Dielectric Breakdown Voltage According to Flow Velocity and Temperature of Vegetable Oils)

  • 최순호;허창수
    • 전기학회논문지
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    • 제61권6호
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    • pp.821-826
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    • 2012
  • The streaming electrification process of vegetable insulating oils occurring when the oils contacted with solid material in a high power transformer circulation system seems to cause electrical discharge incidents and may cause failures. We therefore measured the dielectric breakdown voltage tendency of vegetable insulating oils flowing on the surface of the charging device with various velocity and temperature. First, the relation between the velocity and breakdown voltage tendency of vegetable oils, can be explained by volume effect and v-t effect. Second, experimental results show that applied voltage have little effect on dielectric breakdown voltage, when vegetable insulating oils used for large power transformer.

$SF_6$ 가스절연변압기에서 권선의 섹션에 대한 절연내력 연구 (A Study on the Dielectric Strength in Section of Winding in SF6 Gas Transformer)

  • 허우행;하영식;홍정표;김규탁
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제49권3호
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    • pp.152-158
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    • 2000
  • This paper deal with the experimental discussion about the impulse and AC dielectric strength of SF6 gas insulated transformer. Test sample is measured the dielectric breakdown voltage about modeling of the first and second section which is the weakest for surge voltage. The AC breakdown voltage is appeared 1.4 times than impulse breakdown voltage, so we can estimate that the impulse breakdown voltage is severe to AC breakdown voltage, and when the impulse is applied, in case of lmm tapping with Nomex paper, the characteristics of dielectric breakdown voltage is same to that in oil immersed transformer when SF6 gas pressure is 2.2kg/$cm^2$G.

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바리스터의 물성에 미치는 열처리 효과 (Effect of Heat Treatment on Properties of Varistors)

  • 홍경진;민용기;오수홍;조재철
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.955-958
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    • 2001
  • The structure characteristics of varistor of Zn oxide to depend on the breakdown voltage has been investigated to annealing condition by additive material of Sb$_2$O$_3$ system. The breakdown voltage that has not doping Sb$_2$O$_3$ was 235[V]. ZnO varistors was shown ohmic properties when it's applied voltage was below critical voltage. It was shown non-ohmic properties over critical voltage, because current was increased with decreasing resistance. High voltage ZnO varistors had high breakdown voltage, but it had bad electrical stability with various surge. Sb$_2$O$_3$was increased non-linear coefficient in ZnO varistors grain boundary.

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광유 중 절연파괴전압의 분산과 절연파괴진전 과정의 분석 (Analysis of Breakdown Voltage Dispersion and Breakdown Process in Mineral Oil)

  • 임동영;박숭규;박철호;김기채;이광식;최은혁
    • 조명전기설비학회논문지
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    • 제29권6호
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    • pp.35-41
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    • 2015
  • This paper presents a breakdown voltage and a process of breakdown progress in mineral oil under an quasi-uniform field with decomposition products which occur after the oil discharge. The breakdown voltage in the oil revealed the characteristics of dispersion regardless of an electrode gap. The cumulative probability distribution was used to analyze the dispersion of the breakdown voltage. In addition, the process of breakdown progress in the oil can be reasonably described by the electron breakdown theory based on both electrons emitted from the cathode and ions by field-aided dissociation of the oil. The proposed breakdown process will be used for the basic data to explain the behavior pattern of the decomposition product to cause the dispersion of the breakdown voltage.

Measurement of a Threshold Initiation Carrier Density for a Reduction in Gas Breakdown Voltage

  • Park, Hyunho;Kim, Youngmin
    • Journal of Electrical Engineering and Technology
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    • 제13권6호
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    • pp.2421-2424
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    • 2018
  • A direct measurement of an initiation carrier injection for a low voltage discharge is presented. A self-sustained pulsed discharge is utilized to characterize electrical responses of a glow discharge for varying amounts of injected initiation carriers. It is clearly demonstrated that the initiation carrier injection affects the ignition time and the breakdown voltage of the primary discharge. An abrupt reduction in the breakdown voltage for a $300{\mu}m$ gap pin-plate discharge is observed when a threshold carrier density of $3{\times}10^{11}cm^{-3}$ is injected and the breakdown voltage continues to decrease to 250 V with increasing the initiation carrier injection beyond the threshold density.