• 제목/요약/키워드: current capacity

검색결과 2,588건 처리시간 0.039초

$\mu$SMES 코일용 초전도도체의 전류용량에 관한 연구 (Study on Current Capacity of the SC Conductor for $\mu$SMES Coil)

  • 김해종;성기철;조전욱;진홍범;류강식;류경우
    • 한국초전도ㆍ저온공학회논문지
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    • 제1권1호
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    • pp.22-27
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    • 1999
  • Recently, small-sized superconducting magnetic storage($\mu$SMES) coils become commercially as an energy storage device for a power conditioner. In design and fabrication of the $\mu$SMES coils, to determine optimum current capacity of the superconducting(SC) conductors is one of the important things. We thus investigated the effect of conductor's current capacity, current density, and stability on the coil's maximum stored energy density in consideration of AC losses and switching device's capacities in a power converter. The results show that the smaller current capacity of the SC conductors is preferred for the $\mu$SMES coils but can increase their induced voltage excessively.

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가공선용 나전선의 허용전류 산정 보완 (Complementary Calculation of Current Carrying Capacity for Bare Overhead Conductors)

  • 손홍관;이은웅
    • 대한전기학회논문지:전력기술부문A
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    • 제51권5호
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    • pp.225-231
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    • 2002
  • Many standards have Published for calculating of current carrying capacity for bare overhead conductors. Although these standards use the same basic heat balance concept, they use different approaches to calculate current carrying capacity, This paper looks at the four approaches used to calculate individual heat balance terms, at the overall impact of these terms on the current carrying capacity And this paper is proposed to the selection of proper standard and AC resistance within a country conditions for calculating the current carrying capacity of bare overhead conductors. So current carrying capacities are Proposed to some of conductors.

전력계통에 초전도한류기 적용시 차단용량 확보를 위한 초전도한류기 적용방안 연구 (Analysis on the Application Capacity of the Superconducting Fault Current Limiter considering Reclosing and Fault Current)

  • 김진석;임성훈;김재철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2015년도 제46회 하계학술대회
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    • pp.592-593
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    • 2015
  • Recently, the fault current has increased to exceed the rated breaking capacity of protective device due to the growth of the power demand on the power system where is changed into the loop-, mesh-, network grid. To limit fault current, the superconducting fault current limiter (SFCL) is announced with various methods. In many researches, the current limiting effect with the SFCL has been analyzed considering the rated breaking capacity of the CB with one fault condition. However, the power system has various short circuit and operation conditions. In order to select the capacity of the SFCL with reclosing operation and burden of the fault current on the protective device, the characteristics of the power system were investigated. Through the analysis, the evaluation method of the current rate was improved.

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싸이리스터 컨버터부하에 적용되는 병렬형 능동필터의 적정용량산정 (Capacity Requirement Estimation of Shunt Active Power Filter for Thyristor Converter Load)

  • 박노중;정승기
    • 대한전기학회논문지:전기기기및에너지변환시스템부문B
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    • 제48권12호
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    • pp.715-726
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    • 1999
  • This paper estimates the capacity of shunt type active power filters(APF) for harmonic/reactive power compensation with a thyristor converter load. The base capacity requirement of APF is defined for idealized converter load current waveform and the effect of commutation overlap on the APF capacity is examined. The APF capacity required for reactive power compensation in addition to the harmonic elimination is estimated to give maximum achievable power factor for various operating condition of the partially-loaded thyristor converter. The method of current limit of APF is introduced, and it is shown that the APF capacity can be considerably reduced by deliberately limiting the peak current while maintaining the filtering performance to meet the level std 519 regulation.

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전력 계통 신뢰도 개선을 위한 대표적인 한류기 유형 및 적용 효과 분석 (Review of Typical Fault Current Limiter Types and Application Effect to Improve Power System Reliability)

  • 고윤석;이우철
    • 한국전자통신학회논문지
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    • 제18권6호
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    • pp.1133-1142
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    • 2023
  • 전력 계통에서 전력 용량의 급격한 증가는 고장 용량이 차단기의 차단 용량을 초과하게 함으로써 계통의 신뢰도를 심각하게 저하시킬 수 있다. 한류기는 고장 용량을 차단 용량 레벨로 제한함으로써 신뢰도를 개선할 수 있는 실질적이고 효과적인 방법이다. 본 연구에서는 한류기의 전력계통 적용 시 적용 방법론을 개발하는 데에 도움이 될 수 있도록 먼저, 한류기의 유형별 구조와 동작원리를 분석하였으며 주요 장단점들을 비교하였다. 다음, 한류기의 전력 계통에 대한 적용 효과를 검증하기 위해 한류기가 도입된 전력계통을 모델링하였다. 끝으로, EMTP-RV를 이용하여 3상 단락 고장을 모의한 후, 한류기의 적용 전과 후의 전류를 비교를 통해 한류기에 의해 고장 전류 감소하는 것을 확인함으로써 적용 효과를 검증할 수 있었다.

사질토층을 지나 풍화암에 소켓된 매입 PHC말뚝에서 지반의 허용압축지지력 산정도표 및 산정공식 개발에 관한 연구(II) - 설계 사례 분석을 통한 매입 PHC말뚝의 설계 개선 방향 - (Study(II) on Development of Charts and Formulae Predicting Allowable Axial Bearing Capacity for Prebored PHC Pile Socketed into Weathered Rock through Sandy Soil Layer - Improvement Measures of Current Design Method by Analyzing Current Design Data for Prebored PHC Piles -)

  • 여규권;윤대희;윤도균;최용규
    • 한국지반공학회논문집
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    • 제35권8호
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    • pp.31-42
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    • 2019
  • 최근에 시공된 건축현장의 73개 설계 자료를 분석하여 매입 PHC말뚝에 대한 설계 현황을 고찰하였다. 매입 PHC말뚝의 설계에서 사용하고 있는 극한지지력 산정공식에 따라 산정한 전체지지력에 대한 주면마찰력의 분담율(SRF)는 20~53%로 나타났다. 극한주면마찰력이 과소평가되는 지지력 산정공식에 대한 개선이 필요한 것으로 판단되었다. PHC말뚝의 재료 성능에 대한 평균 설계 효율은 약 70%이었으며 지반 지지력에 대한 평균 설계 효율은 약 80%이었다. 즉, 지반의 설계 효율은 PHC말뚝의 설계 효율보다 약간 높은 수준으로 나타나고 있었다. 이는 지반 지지력을 설계하중보다 동등한 수준 또는 그것보다 약간 높은 수준으로 계산하고 있는 설계 현황에 기인한 것으로 판단되었다. 지반의 허용지지력을 PHC말뚝의 허용연직압축하중보다 높은 수준으로 산정하여야 할 것으로 판단되었다. 매입 PHC말뚝의 지지력 산정공식에서는 극한주면마찰력이 극한선단지지력보다 상대적으로 2.2배 정도 낮은 수준으로 계산되었다. 매입 PHC말뚝의 설계에서 적용하고 있는 극한지지력 산정공식들은 모두 국외 지반을 대상으로 개발되었으며 국내 지반에 대한 적용성 검증 없이 도입되어 사용되어 오고 있었다. 매입 PHC말뚝의 설계에서 적용할 지지력 산정공식의 개선이 이루어져야 할 것으로 판단되었다.

전압 불평형 조건에서 스위칭 소자의 전류용량을 고려한 MMC-HVDC 순환전류 제어기법 (Circulating Current Control in MMC-HVDC Considering Switching Device Current Capacity under Unbalanced Voltage Conditions)

  • 김춘성;정승환;황정구;박성미;박성준
    • 조명전기설비학회논문지
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    • 제30권1호
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    • pp.55-65
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    • 2016
  • This paper proposed a new control method which is capable of controlling circulating current considering current capacity of switching device. In the unbalanced voltage conditions, active power and reactive power have double line frequency. Thus, in order to provide active power without ripple, it is necessary to inject the negative sequence current components. However, when the negative current components is injected, it increases the total current flowing in the Arm, and in the Sub-module(SM) the current more than rated is impressed, which leads to destroy the system. Also, in impressing the circulating current reference of each arm, conventional control method impressed applicable $i_{dck}/3$ in the case of balanced voltage conditions. In the case of unbalanced conditions, as arm circulating current of three phase show difference due to the power impressed to each arm, reference of each arm is not identical. In this study, in the case of unbalanced voltage, within permitted current, the control method to decrease the ripple of active power is proposed, through circulating current control and current limitations. This control method has the advantage that calculates the maximum active power possible to generate capacity and impressed the current reference for that much. Also, in impressing circulating current reference, a new control method proposes to impress the reference from calculating active power of each phase. The proposed control method is verified through the simulation results, using the PSCAD/EMTDC.

송전선로의 설비특성을 고려한 운영그룹 분류 및 최고허용온도 (An Operation Grouping and Its Maximum Allowable Conductor Temperature Considering Facility-conditions of Transmission Lines)

  • 손홍관;김병걸;박인표;안상현;장태인;최종기
    • 전기학회논문지
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    • 제57권11호
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    • pp.1922-1928
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    • 2008
  • The thermal rating of a conductor are maximum continuous current capacity and short time emergency current capacity. The overload operation for a faults have an effect on a conductor lifetime. Its time duration and overload level are limited to facility conditions of transmission lines. The short time emergency current capacity in KOREA observe the KEPCO's DESIGN RULE 1210, but its rules are not included to concept of an allowable short time duration. This papers are described to the calculation concept of short time emergency current capacity considering a time duration and an overload level. And we suggested a operation grouping and its maximum conductor temperature considering facility conditions - conductor lifetime, stability of connection points, conductor height above ground and clearance, in the operating and new T/L.

초전도전류생성기의 스위칭 특성 (Switching Characteristics of a Superconducting Current Limiter)

  • 차귀수;한송엽
    • 대한전기학회논문지
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    • 제39권12호
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    • pp.1239-1245
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    • 1990
  • With the rapid growth of power system capacity, fault current levels approach the maximum capacity of circuit breakers. In this paper, a superconducting current limiter (SCL) is proposed to reduce the fault current to an appropriate level. Superconductor for SCL has been examined and design criterion of each triggering method has been shown. Thin film SCL has been fabricated and switching characteristics are shown, where thermal and current triggering methods are adopted. Experimental result shows that fault current is reduced to one-half.

Bi-2223초전도 선재의 접합공정 연구 (A study of joining method of BSCCO(2223) tape)

  • 김정호;김태우;주진호;서수정
    • 한국초전도저온공학회:학술대회논문집
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    • 한국초전도저온공학회 1999년도 제1회 학술대회논문집(KIASC 1st conference 99)
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    • pp.18-21
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    • 1999
  • The effects of joining process such as contact method, shape of joined area and pressure on the properties of Bi-2223 superconducting tape have been optimized. In the process tapes were etched to expose the superconductor core in the shape of 'ㅁ' and 'ㄷ'. The exposed cores of the two tapes were brought into contact, uniaxially pressed and sintered. Subsequently, the current capacity of the joined tape was measured as a function of uniaxial pressure. It was observed that the current capacity was significantly dependent on uniaxial pressure. The joined tape, fabricated with a pressure of 1,600 MPa, showed the highest value of current capacity(90%) of highest value of current capacity is resulted from improvements in core density, contacting area and grain alignment, etc. In addition the effect of processing variables on microstructural evolution and mechanical property of joined tape will be presented.

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