• Title/Summary/Keyword: limiter

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Study on the Necessity for Limiting Impedance of Superconducting Fault Current Limiter Considering Protective Coordination of power distribution (배전보호협조를 고려한 초전도 한류임피던스 제한에 필요성 연구)

  • Ahn, Jae-Min;Kim, Jin-Seok;Moon, Jong-Fil;Lim, Sung-Hun;Kim, Jae-Chul
    • Proceedings of the KIEE Conference
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    • 2008.11a
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    • pp.34-36
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    • 2008
  • In this paper, we study on the necessity for limiting impedance of Superconducting Fault Current Limiter(SFCL) considering protective coordination. Several countermeasures have been proposed to protect the power system effectively from the larger fault current. Among them, the SFCL has been expected as one of the most effective solutions. However, the application of SFCL into power system can cause some problems, such as non-operation of instantaneous elements, of protective coordination because of limiting fault current. So we suggest that impedance of SFCL is must limited for operation of instantaneous elements. 'This method is essential to introduce application of SFCL into power distribution system.

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Analysis of Transmission Power System with Superconducting Fault Current Limiter for Reducing a Fault Current (초전도 한류기 적용을 통한 모의 송전계통의 고장 전류 저감 분석)

  • Kim, Myong-Hyon;Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul;Choo, Dong-Wook
    • Proceedings of the KIEE Conference
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    • 2011.07a
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    • pp.718-719
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    • 2011
  • Lately, the demand for electrical power has been significantly increased. As a result a power transmission system has been improved. On the other hand fault current increased more than past. Superconducting fault current limiter (SFCL) is one of the solutions to limit fault current. However, SFCL's research has not advanced in a power transmission system fully. Therefore, we studied effect of SFCL in a power transmission system. The power distribution system is open-loop circuit, but a power transmission system is closed-loop system. Consequently, Fault current in a power transmission system is larger than fault current in a power distribution system. we exerimented a simple closed-loop power transmission system circuit.

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Application Scheme of Resistive HTS-FCL on Future New Distribution System (저항형 초전도한류기의 미래 배전계통 적용방안)

  • Lee Seung-Ryul;Kim Jlong-Yul;Kim Ho-Yong;Yoon Jae-Young
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.54 no.5
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    • pp.212-216
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    • 2005
  • This paper describes the application scheme of resistive HTS-FCL(High Temperature Superconducting-Fault Current Limiter) on future new distribution system. Future new distribution system means the power system to which applies the 22.9kV HTS cable with low-voltage and mass-capacity characteristics replacing the 154kv conventional cable in addition to HTS transformer and HTS-FCL. The fault current of future new distribution system will increase greatly because of the inherent characteristics of HTS transformer/cable and applications of distributed generations and spot networks and so on. This means that the HTS-FCL is necessary to reduce the fault current below the breaking capacity. This paper studies the appropriate location, parameters and the influences of HTS-FCL on future new distribution system. Finally, this paper suggests the reasonable basic parameters of resistive HTS-FCL for future KEPCO new distribution system.

PERFORMANCE OF TWO DIFFERENT HIGH-ACCURACY UPWIND SCHEMES IN INVISCID COMPRESSIBLE FLOW FIELDS

  • Hosseini R;Rahimian M.H;Mirzaee M
    • Journal of computational fluids engineering
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    • v.10 no.1
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    • pp.99-106
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    • 2005
  • Performance of first, second and third order accurate methods for calculation of in viscid fluxes in fluid flow governing equations are investigated here. For the purpose, an upwind method based on Roe's scheme is used to solve 2-dimensional Euler equations. To increase the accuracy of the method two different schemes are applied. The first one is a second and third order upwind-based algorithm with the MUSCL extrapolation Van Leer (1979), based on primitive variables. The other one is an upwind-based algorithm with the Chakravarthy extrapolation to the fluxes of mass, momentum and energy. The results show that the thickness of shock layer in the third order accuracy is less than its value in second order. Moreover, applying limiter eliminates the oscillations near the shock while increases the thickness of shock layer especially in MUSCL method using Van Albada limiter.

Analysis on Current Limiting Characteristics of a Hybrid SFCL with the First Half Cycle Limiting Operation Due to Resistance of Superconducting Element (초전도소자의 저항변화에 따른 반주기내 한류형 하이브리드 초전도 전류제한기의 전류제한 특성 분석)

  • Kim, Jin-Seok;Lim, Sung-Hun;Kim, Jae-Chul;Choi, Jong-Soo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.60 no.10
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    • pp.1817-1822
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    • 2011
  • The fault current has been increasing due to expansive substation facilities for meeting the increase of demand. To limit increasing fault current in a power system, among methods the superconducting fault current limiter (SFCL) has been considered to be adopted in the power grid. However, in case of adopting SFCL in the power system, most of SFCLs need to solve problems such as recovery, cost. With efforts to solve those problems, the novel fault current limiting device which is called hybrid SFCL is developed. To apply the hybrid SFCL, it has to be needed to analyze application possibility and itself operation characteristics. In this paper, the fault current limiting and operation characteristics of hybrid SFCL with first half cycle the limiting operation in case of various resistances of superconducting element were analyzed through experiment.

Analysis of the Protective Coordination considering the superconducting fault current limiter in Distribution System with Distributed Generation (분산전원 연계 계통에 초전도한류기 적용 시 보호협조 분석)

  • Seo, Hun-Chul;Ko, Yun-Tae;Rhee, Sang-Bong;Kim, Chul-Hwan;Kim, Jae-Chul;Hyun, Ok-Bae
    • Proceedings of the KIEE Conference
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    • 2009.07a
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    • pp.137_138
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    • 2009
  • The increasing of fault current by introducing of the distributed generation(DG) in distribution system disrupts the protective coordination. Therefore, this paper applies the superconducting fault current limiter(SFCL) to solve this problem. The distribution system with DG and SFCL is modeled by EMTP. According to various size of the DG, the fault is simulated and the operating time of overcurrent relay is investigated accoring to the resistance of SFCL.

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Analysis on SFCL's Impedance for Protective Coordination in Large Transformer installed in Distribution Substation (배전변전소에 대용량변압기로 교체 적용시 보호협조를 위한 초전도 전류제한기의 임피던스 분석)

  • Kim, Jin-Seok;Kim, Myoung-Hoo;You, Il-Kyoung;Moon, Jong-Fil;Lim, Sung-Hun;Kim, Jae-Chul;Ahn, Jae-Min
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.58 no.8
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    • pp.1479-1484
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    • 2009
  • The introduction of the large transformer due to the large power demand has increased the fault current in power distribution system. The increased fault current can exceed the cut-off ratings of the circuit breaker. As the methods to solve this problem, the superconducting fault current limiter(SFCL) has been notified. However, the limited fault current by SFCL affects the operational characteristics of the protective device such as overcurrent relay. Therefore, the selection of the proper impedance for the SFCL is required to keep overcurrent relay's protective coordination with the SFCL when a large transformer is introduced into the distribution system. In this paper, the SFCL's impedance for protective coordination was investigates in that a large transformer is introduced.

Analysis on Current Limiting Characteristics According to the Influence of the Magnetic Flux for SFCL with Two Magnetic Paths

  • Ko, Seok-Cheol;Han, Tae-Hee;Lim, Sung-Hun
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.1909-1913
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    • 2014
  • In this study, a superconducting fault current limiter (SFCL) having two magnetic paths was proposed, and its current limiting characteristics were analyzed. For the SFCL to effectively perform the current limiting operation, it must be designed considering the magnetic saturation of the E-I core. Further, the influence of the magnetic flux on its peak current limiting characteristics was investigated. In addition, the magnetic flux curves of the SFCL obtained from the fault current limiting experiments were analyzed, and the subtractive polarity winding case was observed to not only further reduce the saturation potential of the core but also perform the peak current limiting functions well when compared with the additive polarity winding case.

Analysis on Fault Current Limiting Characteristics According to Peak Current Limiting Setting of a Flux-Lock Type SFCL with Peak Current Limiting Function (피크전류제한 설정에 따른 피크전류제한 기능을 갖는 자속구속형 초전도한류기의 고장전류제한 특성 분석)

  • Ko, Seok-Cheol
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.26 no.12
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    • pp.68-73
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    • 2012
  • In this paper, the fault current limiting characteristics of a flux-lock type superconducting fault current limiter (SFCL) with peak current limiting function were analyzed through its short-circuit tests. The setting condition for the peak current limiting operation was derived from its electrical equivalent circuit, which was dependent on the inductance ratio between the third coil and the first coil. Through the analysis on the short-circuit tests for the flux-lock type SFCLs with the different inductance ratio between the third coil and the first coil, the setting value for the peak current limiting operation of the flux-lock type SFCL with peak current limiting function could be confirmed to be adjusted with the variation of the inductance ratio between the third coil and the first coil.

PLL Strategy Hating Frequency Limiter and Anti-windup Suitable to UPS (무정전전원장치에 적합한 주파수 제한기와 안티 와인드업을 가지는 PLL 방식)

  • Ji Jun-Keun;Kim Hyo-sung;Sul Seung-Ki;Kim Kyung-Hwan
    • Proceedings of the KIPE Conference
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    • 2004.07b
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    • pp.778-782
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    • 2004
  • 본 논문에서는 전력 품질 기기의 제어에 있어서 필수적 요소라고 할 수 있는 전원각을 찾는 방법중에서 PLL(Phase Locked Loop)에 관하여 기존의 방식들을 먼저 알아보고, 정상분을 추출하여 이용하는 기존의 PLL 방식을 무정전전원장치에 적합한 형태로 개선한 주파수를 제한한 PLL 방식을 제안하였다. 제안된 PLL 방식은 기존의 PI 제어기에 주파수 제한기(limiter)와 안티 와인드업(anti-windup)을 추가하였다. 이것의 기본적인 동작 원리는 기존의 방법들과 같지만, 차이점은 주파수 제한기의 삽입으로 인하여 주파수 변동률을 일정한 범위 내에서 제한할 수 있다는 것이다. 기존의 PLL 방법과 본 논문에서 제안된 주파수를 제한한 PLL 방법의 차이를 알아보기 위하여 동적 전압 보상기로 전압을 보상하는 시뮬레이션을 하였고, 결과적으로 제안된 주파수를 제한한 PLL 방법이 기존의 PLL 방법보다 UPS에 적합함을 입증하였다.

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