• Title, Summary, Keyword: Short line fault

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Current Limiting Characteristics According to the Increase of Voltage in Separated Three-Phase Flux-Lock Type Superconducting Fault Current Limiter Using YBCO CC (YBCO CC를 이용한 분리된 삼상 자속구속형 고온초전도 전류제한기의 전압 증가에 따른 전류제한 특성)

  • Doo, Seung-Gyu;Du, Ho-Ik;Kim, Min-Ju;Kim, Yong-Jin;Lee, Dong-Hyeok;Han, Byoung-Sung
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.355-356
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    • 2009
  • In this paper, we investigated the fault current limiting characteristics according to the increase of voltage in the separates three-phase flux-lock type high-Tc superconducting fault current limiter using YBCO CC. The separated three-phase flux-lock type SFCL consists of single-phase flux-phase type SFCL in each phase. Superconductor was using the YBCO CC. To analyze the current limiting characteristics of a three-phase flux-lock type SFCL, the short circuit experiments were carded out fault such as the triple line-to-ground fault. The experimental result shows that fault current limiting characteristics was improved on the high voltage level.

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A study on the detection of poor contact and arcing fault using a fuzzy logic (퍼지논리를 적용한 전기적 접촉불량 및 아크 검출에 관한 연구)

  • Kim, Hyun-Woo;Kim, In-Tae
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • pp.205-210
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    • 2007
  • This study on the prevention of electric fire. Generally the electric fire is caused by break or disconnection of the power line, short circuit and poor contact, arcing fault ect. In these causes, this paper is studied on the detection of poor contact and arcing fault. The arcing fault is caused by poor contact mainly. The arcing fault can occurs a electric fire by interaction of flammable gas and materials and it can be caused of tracking and carbonization. These phenomenons is also caused of electric fire. Therefore this paper is studied on the detection of arcing fault and poor contact.

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The Simulation of Transmission Line Fault-Induced Noise Signals. (선로고장시 발생되는 잡음의 시뮬레이션)

  • Shin, Myung-Chul;Kim, Mu-Woong;Kim, Chul-Hwan
    • Proceedings of the KIEE Conference
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    • pp.454-456
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    • 1987
  • A more specialized area of transient evaluations is transmission line fault-detecting and protection system. During the first cycle or two following a power system fault, a high-speed protective relay is expected to make a decision as to the severity or location of the fault, usually based on 60 Hz information, i.e. the phase and magnitude of 60 Hz voltage or current signals. It is precisely at this time however that the signal is badly corrupted by noise, in the form of a de offset or frequencies above 50 Hz. One of several possible sources of transients in protection measuring signals is in the primary system for which protection is required in its response to the impact of short circuit fault on-set. Other sources are in the primary voltage and current transducers from which protection signals are derived, and, often of particular importance, in the interface circuits between the transducer secondaries and the comparator and measuring elements of the protection system. However, the noise signals that will be described in this paper are due to the main power system only and do not include errors due to current or voltage transducers.

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Short Circuit Tests of the Three-Phase DC Reactor Type Fault Current Limiter in Changing of Turns Ratio of Transformers (변압기 권선비의 변화에 따른 3상 DC 리액터형태 한류기의 단락실험)

  • Lee, Eung-Ro;Lee, Chan-Ju;Lee, Seung-Je;Go, Tae-Guk;Hyeon, Ok-Bae
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.6
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    • pp.267-272
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    • 2002
  • This Paper deals with the short circuit tests of the three-Phase DC reactor type fault current limiter (FCL) in changing of turns ratio of transformers. The experiment of this paper is a preliminary step to develop the FCL's faculties for an application to high voltage transmission line. So, superconducting coil was made of Nb-Ti, low temperature superconductor, and the ratings of the power system of experimental circuit are 400V/7A class. A three-phase DC reactor type FCL consists of three transformers, six diodes, one superconducting coil and one cryostat. The important point of experimental analysis is transient period, the operating lagging time of circuit breaker. As the results of the experiment, the values are referred to the limitation rate about 77% and 90% when the turns ratio of transformer was 1:1 and 2:1 respectively.

Fault simulation of distributed power system with superconducting fault current limiter (초전도 사고전류제한기를 설치한 독립배전계통의 고장상태해석)

  • Lee, Sang-Jin;Oh, Yun-Sang;Bae, Joon-Han;Ko, Tae-Kuk
    • Proceedings of the KIEE Conference
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    • pp.122-124
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    • 1995
  • Electrical transmission and distribution networks must withstand an occasionally abnormal condition such as a fault, with prejudicial consequences for the line, transformers or generators. And the improvement of reliability and quality of the delivered power from an electric utility motivates the development of new technologies in power applications. As a part of these studies, the usefulness and utility of a superconduction fault current limiter(SFCL) are shown. The SFCL is applied to 22.9KV three-phase power system and performed short circuit studies. The verified quench characteristic of SFCL is adopted for fault simulation and the results are compared with those of system which have not SFCL.

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On the Current Limiting Characteristics and Parameters of Superconducting Fault Current Limiter Introduced to 345kV Electric Power System due to Resistive-Type, Reactive-Type (유도형과 저항형 초전도한류기의 파라메타를 고려한 전력계통도입효과의 분석 및 고찰)

  • 홍원표;김용학;전영환;이승학
    • Proceedings of the Korea Institute of Applied Superconductivity and Cryogenics Conference
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    • pp.285-290
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    • 2002
  • Power systems are becoming larger and larger for meeting electric power demand. Therefore, the over-currents resulting from contingencies such short circuits are increasing higher. The Maximum short circuit current of modern power system is becoming so large that circuit breaker are not expected th be able to shut down the current in the future. In order to cut over-currents, a system composed of a superconducting fault current limiter(SFCL) and traditional breaker seems to provide a promising solution for future power operation. In present paper, three line-to-ground fault is assumed to happen at the center of 345kV transmission lines in a large capacity electric power system The superconducting fault current limiter was represented using a commutation type, which consists of a non-inductive superconducting coil and current limiting element(resistor or reactor). The introduction merits of the SFCL were investigated quantitatively by RTDS/EMTDC from the viewpoint of current limiting performance, the prevention of the voltage drop at the load bus and comparison characteristics for two type SFCL. Desired design specification and operation parameters of SFCL were also given qualitatively by the performance evaluation of the two type SFCL in the power system.

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Development of Arc Fault Circuit Interrupter Using the Distorted Voltage Wave in Electric Arc Faults (아크사고 발생 시 전압 왜형파를 이용한 아크차단기 개발)

  • Kwak, Dong-Kurl
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.6
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    • pp.876-880
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    • 2013
  • The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The principal factor of the fire is electric arc or spark accompanied with such electric faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To improve such problems, this paper studies on an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. The proposed voltage sensing type AFCI is an electrical fire prevention apparatus of new conception that operates a circuit breaker with sensing the instantaneous voltage drop of line voltage at electrical faults occurrence. The proposed AFCI is composed of control circuit topology using some semiconductor switching devices. Some experimental tests of the proposed AFCI confirm practicality and the validity of the analytical results.

A Study on Module Design and Performance of Polymer Arrester (폴리머 피뢰기의 모듈 설계 및 성능에 관한 연구)

  • Cho, Han-Goo;Chun, Jong-Uk;Kang, Yeong-Kil
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.108-111
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    • 2003
  • The main objective of this paper is to module design and pressure relief test a new type of polymer gapless surge arrester for power distribution line. Metal oxide surge arrester for most electric power system applications, power distribution line and electric train are now being used extensively to protect overvoltage due to lightning. Surge arresters with porcelain housing must not have explosive breakage of the housing to minimize damage to other equipment when subjected to internal high short circuit current. When breakdown of gapless elements in a surge arrester occurs due to flashover, fault short current flows through the arrester and internal pressure of the arrester rises. The pressure rise can usually be limited by fitting a pressure relief diaphragm and transferring the arc from the inside to the outside of the housing. However, there is possibility of porcelain fragmentation caused by the thermal shock, pressure rise, etc. Non-fragmenting of the housing is the most desired way to prevent damage to other equipment. The pressure change which is occurred by flashover become discharge energy. This discharge energy raises to damage arrester housing and arrester housing is dispersed as small fragment. Therefore, the pressure relief design is requested to obstruct housing dispersion.

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Safely Evaluation on Common Grounding System for Electric Railway (전기철도의 공용접지 시스템에 대한 안정성 평가에 관한 연구)

  • Song, Jin-Ho;Hwang, Yu-Mo
    • The Transactions of the Korean Institute of Electrical Engineers B
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    • v.51 no.6
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    • pp.298-306
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    • 2002
  • We performed an safety evaluation on constructing of a common grounding system for electrical railway in view of its efficacy and technical fit. In order to compare the conventional grounding method, which has been individually conducted, with the common grounding with all ground wires connected in common to the counterpoise buried below the surface of the earth in parallel with rail, we set up scenarios with several cases of fault and load conditions in Chungbuk railway sections with the common grounding system. Based on models for railway conductors including the grounded system, line Parameters of railway power system are computed. The circuit model for power system with up and down lines, auto-transformers and railway substations is used to compute impedances of counterpoise and substation ground net. For each scenario with faults and operation conditions of railway, the induced potentials on signal and communication lines are also computed. It is shown that the common grounding for Chungbuk railway is superior experimentally to the conventional method in three respects: (1) the lower rail potentials during operation of railway in line, (2) the lower rail potentials for short-circuit faults between catenary and rail, and (3) the lower stress voltages on signal and communication lines for short-circuit or ground faults. The analysis results confirm that the grounding system for electric railway is required to be built by the common grounding and be evaluated on its safety in design.

Comparison of Fault Current Limiting Characteristics between the separated Three-phase Flux-lock Type SFCL and the Integrated Three-phase Flux-lock Type SFCL (분리된 삼상 자속구속형 전류제한기와 일체화된 삼상 자속구속형 전류제한기의 전류제한 특성 비교)

  • Doo, Seung-Gyu;Du, Ho-Ik;Kim, Min-Ju;Park, Chung-Ryul;Kim, Yong-Jin;Lee, Dong-Hyeok;Han, Byoung-Sung
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.8
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    • pp.689-693
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    • 2009
  • We investigate the comparison of fault current characteristics between the separates three-phase flux-lock type superconducting fault current limiter(SFCL) and integrated three-phase flux-lock type superconducting fault current limiter(SFCL). The single-phase flux-lock type SFCL consists of two coils. The primary coil is wound in parallel to the secondary coil on an iron core and superconducting elements are connected to secondary coil in series. Superconducting elements are used by the YBCO coated conductor. The separated three-phase flux-lock type SFCL consists of single-phase flux-phase type SFCL in each phase. But the integrated three-phase flux-lock type SFCL consists of three-phase flux-reactors wound on an iron core. Flux-reactor consists of the same turn's ratio between coil 1 and coil 2 for each single phase. To compare the current limiting characteristics of the separated three-phase flux-lock type SFCL and integrated three-phase flux-lock type SFCL, the short circuit experiments are carried out fault condition such as the single line-to-ground fault. The experimental result shows that fault current limiting characteristic of the separated three-phase flux-lock type SFCL was better than integrated three-phase flux-lock type SFCL. And the integrated three-phase flux-lock type SFCL has an effect on sound phase.