• 제목/요약/키워드: Resistive current

검색결과 450건 처리시간 0.023초

낮은 변환손실과 높은 LO-RF 격리도 특성을 갖는 94 GHz Resistive Mixer 의 제작 (Fabrications of Low Conversion Loss and High LO-RF Isolation 94 GHz Resistive Mixer)

  • 이복형;이진구
    • 대한전자공학회:학술대회논문집
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    • 대한전자공학회 2005년도 추계종합학술대회
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    • pp.921-924
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    • 2005
  • We report low conversion loss and high LO to RF isolation 94 GHz MMIC resistive mixers based on 0.1 ${\mu}m$ InGaAs/InAlAs/GaAs metamorphic HEMT technology. The fabricated resistive mixers applied a one-stage amplifier on RF port of the mixer. By using the one-stage amplifier, we obtained the decrement of conversion loss and the increment of LO to RF isolation. So, we can obtain higher performances than conventional resistive mixers. The modified mixer shows excellent conversion loss of 6.7 dB at a LO power of 10 dBm. We also observed an extremely high isolation characteristic from the MMICs exhibiting the LO-RF isolation of 21 ${\pm}$ 0.5dB in a frequency range of 93.7${\sim}$ 94.3 GHz. The low conversion loss and high LO-RF isolation characteristics of the MMIC modified resistive mixers are mainly attributed to the performance of the MHEMTs exhibiting a maximum transconductance of 654 mS/mm, a current gain cut-off frequency of 173 GHz and a maximum oscillation frequency of 271 GHz.

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박막 저항형 초전도 한류기의 용량증대를 위한 방안 (Increase of resistive type superconducting fault current limiter capacity)

  • 차상도;김혜림;최효상;현옥배
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 B
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    • pp.790-792
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    • 2002
  • The resistive type superconducting fault current limiter(SFCL) is a current limiter using the Quench mechanism of superconductors. When Quench occurs in superconductors, the resistance of superconductors increases abruptly. In order to increase SFCL capacity, current limiting elements were connected in series. If the Quench current of each element was different, voltage distribution was imbalanced. This imbalance could be removed by arrangement including series and parallel connection of elements. Based on this result, an SFCL of 1.8kV/50A was designed and experimented, expecially, in terms of increasing the voltage rating.

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고온초전도체를 이용한 차폐유도형 전류제한기의 설계 및 동작 특성해석 (The design and analysis of Operational characteristic of Shielded Inductive Fault Current Limiter using high-$T_c$ Superconducting)

  • 송재주;이재;임성훈;강형곤;한병성
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.339-342
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    • 2001
  • In this paper, the characteristics of the shielded inductive superconducting fault current limiter(FCL) were simulated and analyzed to search for the parameter to determine FCL operation, Fault current limiting operation can be executed as resistive or inductive type, which is determined by iron-core radius and the number of the primary coil turns. It was considered through this paper that the operation of each was compared and examined about the merit of each mode.

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18kV 배전용 피뢰기의 누설전류 분석 (Leakage Current Analysis of 18 kV Lighting Arrester)

  • 박정남;이용희;신양섭;서정민;장수형
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 C
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    • pp.1906-1908
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    • 2002
  • In general, ZnO lighting arrester are known to exhibit an increases in resistive current with time, the rate of increase being exacerbated with increasing applied voltage. In addition, since the resistive leakage current caused by deterioration of ZnO lighting arrester mainly caused an increase of the third harmonic component, thereby it is possible the arrester degradation diagnosis by measuring the third harmonic component in the total leakage current. So, in this paper, we presents a leakage current measuring and analysis system of 18[kV] ZnO lighting arrester.

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저항형 초전도 한류기에서의 퀀치 전파 (Quench propagation in resistive SFCL)

  • 김혜림;현옥배;최효상;황시돌;김상준
    • 한국전기전자재료학회논문지
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    • 제13권4호
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    • pp.337-342
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    • 2000
  • We fabricated resistive superconducting fault current limiters based on YB $a_{2}$/C $u_{3}$/ $O_{7}$ thin films and investigated their quench propagation characteristics. The YB $a_{2}$/C $u_{3}$/ $O_{7}$ films was coated with a gold layer and patterned into 1 mm wide meander lines by photolithography. The quench was concluded to start locally and propagates until completed. The quench propagation characteristics were explained based on the heat transfer within the film as well as between the film and the surrounding liquid nitrogen. The quench completion time depended strongly on potential fault current amplitude and not significantly on fault angle which indicates that the quench propagation speed is affected more by heat dissipation rate than by fault current increase rate. The quench completion time was 1 msec at the fault current of 65 $A_{peak/{\ak}}$.

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나노 적층 구조를 응용한 저항성 기반 비휘발성 메모리 소자 특성 제어 (Control of Charge Transports in Nonvolatile Resistive Memory Devices through Embedded Nanoscale Layers)

  • 유일환;황진하
    • 한국세라믹학회지
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    • 제46권3호
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    • pp.336-343
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    • 2009
  • Nickel oxide thin films exhibit the resistive switching as a function of applied voltages. The switching phenomena involve low and high resistance states after electroforming. The electrical features are believed to be associated with the formation and rupture of filaments. The set and reset behaviors are controlled by the oxidation and reduction of filaments. The indirect evidence of filaments is corroborated by the presence of nanocrystalline nickel oxides found in high-resolution transmission electron microscopy. The insertion of insulating layers seems to control the current-voltage characteristics by preventing the continuous formation of conductive filaments, potentially leading to artificial control of resistive behaviors in NiO-based systems.

A Study on Transient Numerical Simulation on Heat Transfer Characteristics in the Resistive SFCL

  • Kim Chul-Ho;Lee Kee-Man;Ryu Kyung-Woo
    • 한국초전도ㆍ저온공학회논문지
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    • 제7권4호
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    • pp.14-19
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    • 2005
  • A transient numerical simulation was conducted to have variation of temperature on an element of resistive Superconducting Fault Current Limiter (SFCL) under quench condition. It is very important engineering information for an optimum design of cryogenic system for cooling of a resistive SFCL element. A bifilar coil for resistive SFCL for 10 MVA system was incorporated as a model in this numerical study. From the numerical simulation result, it was found that the averaged temperature on the shunt and Bi-2212 element at 500 kW, 100 ms was 711.1 K and 198.4 K respectively. The temperature variation with the change of the hot-spot size and time is also obtained. The maximum temperature was continuously increased in all cases until the hot-spot stops at 100ms and it was going down after then. Such as, the details of temperature distribution on the SFCL element obtained from this numerical study and it should be very valuable information on the decision of the cooling capacity of cryogenic system.

YBCO 박막형 저항형 한류기에 적용 가능한 Meander Line 해석 연구 (Analytical Investigations on the Figures of Meander Lines on the YBCO Thin Film for Resistive Fault Current Limiters)

  • 이방욱;강종성;박권배;오일성;현옥배
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 2002년도 학술대회 논문집
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    • pp.221-224
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    • 2002
  • Superconducting electrical devices are under development in a national project in Korea. And KEPCO and LGIS are in charge of development of a resistive type fault current limiters(FCLs) with YBCO thin films. In order to realize FCLs, the rated power of FCLs must be increased. For this purpose, it is of great interest to increase of allowed voltage of unit component without electrical and thermal damages. So, meander lines were widely used for the conducting path to increase maximum electric field. In this research, numerical simulations on the electromagnetic behaviors of the device were carried out, especially focusing on the effect of meander line structures on the YBCO thin films. To evaluate the structures of meander lines, three types of meander lines were considered for numerical analysis using finite element method (FEM). In this simulation, both normal state and fault conditions were considered for calculation of electric field, current density, magnetic field density. And the simulation resulted are compared to find the optimum design of meander lines for resistive FCLs.

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위상차를 이용한 저항성 누설전류 측정 알고리즘을 적용한 온라인 전기안전 감시시스템의 개발 및 성능시험 (Development and Performance Test of Online Electrical Safety Monitoring System Applying an Algorithm to Measure Resistive Leakage Currents using Phase Differences)

  • 유정현;김희식;정용욱
    • 한국안전학회지
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    • 제33권3호
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    • pp.27-32
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    • 2018
  • Nowadays, to prevent electrical accidents in Korea, inspectors directly performed checking general electrical facilities as a cycle from every one to three years. It is difficult to presuppose an omen because intact conditions of electrical equipments are not kept at the time of inspection. In this paper, in order to ensure effectiveness of an online basis electric inspection, we developed an electrical safety IoT system using LoRa communication technology to enable monitoring mainly electrical safety components such as overcurrent, overvoltage, resistive leakage current, and power. Then we proposed a method for verifying performances of the prosed electrical safety IoT system. Resistive leakage currents are calculated by using difference of phase between voltages and currents. We verified that average errors are 0.97%, which reference goal is ${\pm}5%$ for a device, through reliability test according to conditions. Results of this research can be used as basic study materials to develop technologies for measuring three phase leakage current and for implementing public electrical safety. platform.

Cr-SrTiO3 박막을 이용한 Si 기반 1D 형태 저항 변화 메모리의 전류-전압 특성 고찰 (Current Versus Voltage Characteristics of a Si Based 1-Diode Type Resistive Memory with Cr-SrTiO3 Films)

  • 송민영;서유정;김연수;김희동;안호명;김태근
    • 한국전기전자재료학회논문지
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    • 제24권11호
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    • pp.855-858
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    • 2011
  • In this paper, in order to suppress unwanted current paths originating from adjacent cells in a passive crossbar array based on resistive random access memory (RRAM) without extrinsic switching devices, 1-diode type RRAM which consists of a 0.2% chromium-doped strontium titanate (Cr-$SrTiO_3$) film deposited on a silicon substrate, was proposed for high packing density, and intrinsic rectifying characteristics from the current versus voltage characteristics were successfully demonstrated.