• Title/Summary/Keyword: digital protection relay

검색결과 86건 처리시간 0.023초

잔류자속에 무관한 변압기 보호용 수정전류차동 계전기 (Modified Current Differential Relay for Transformer Protection Unaffected by Remanent flux)

  • 강용철;김은숙
    • 대한전기학회논문지:전력기술부문A
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    • 제53권9호
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    • pp.500-506
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    • 2004
  • This paper proposes a modified current differential relay for transformer protection unaffected by the remanent flux. The relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. To cope with the remanent flux, before saturation, the relay calculates the core-loss current and uses it to modify the measured differential current. When the core then enters saturation, the initial value of the flux is obtained by inserting the modified differential current at the start of saturation into the magnetization cure. Thereafter, the actual core flux is then derived and used in conjunction with the magnetization curve to calculate the magnetizing current. A modified differential current is then derived that compensates for the core-loss and magnetizing currents. The performance of the proposed differential relay was compared against a conventional differential relay. Results indicate that the modified relay remained stable during severe magnetic inrush and over-excitation because the exciting current was successfully compensated. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. The relay discriminates magnetic inrush and over-excitation from an internal fault and is not affected by the level of remanent flux.

$Y-{\Delta}$ 변압기 보호용 수정 전류차동 계전기 (Modified Current Differential Relay for $Y-{\Delta}$ Transformer Protection)

  • 김은숙;강용철
    • 대한전기학회논문지:전력기술부문A
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    • 제55권3호
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    • pp.95-101
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    • 2006
  • This paper proposes a modified current differential relay for $Y-{\Delta}$ transformer protection. The relay uses the same restraining current as a conventional relay, but the differential current is modified to compensate for the effects of the exciting current. A method to estimate the circulating component of the delta winding current is proposed. To cope with the remanent flux, before saturation, the core-loss current is calculated and used to modify the measured differential current. When the core then enters saturation, the initial value of the flux is obtained by inserting the modified differential current at the start of saturation into the magnetization cure. Thereafter, the core flux is then derived and used in conjunction with the magnetization curve to calculate the magnetizing current. A modified differential current is then derived that compensates for the core-loss and magnetizing currents. The performance of the proposed differential relay was compared against a conventional differential relay. Test results indicate that the modified relay remained stable during severe magnetic inrush and over-excitation, because the exciting current was successfully compensated. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. The relay does not require additional restraining signal and thus cause time delay of the relay.

발전기보호반을 위한 IED의 설계에 관한 연구 (A Study on Design of IED for Generator Protection Panel)

  • 박철원;박성완
    • 전기학회논문지P
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    • 제62권3호
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    • pp.133-138
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    • 2013
  • A large generator is an important role in transferring an electric power to power system. The IEDs of large generator often use microprocessor technology to obtain a digital relay system with a wide range of measuring, protection, control, monitoring, and communication functions. However, all generator protection and control systems in Korea imported from abroad and are being operated. In order to reduce the large expense and improve the reliable operation, development of generator protection and control system by domestic technology is required. This paper deals with the design of the IED of generator protection panel for development of generator protection and control system. The major emphasis of the paper will be on the description of hardware and signal processing test results and measurement accuracy of the prototype IED. By developing of generator IED based on DSP and microprocessor, replacement of the generator protection panel imports are expected to be effective.

오차를 고려한 송전선 보호 거리계전 정정룰에 대한 고찰 (Examination with Transmission Line Distance Relay Setting Rule Considering Error)

  • 조성진;최면송;현승호;김종욱;이주왕;조범섭;유영식
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 A
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    • pp.12-15
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    • 2002
  • Korea Power System Protection Setting Rule was used from the rectify 1990's. Thereafter transmission voltage is raised the voltage into 765kV, and introduction to new technology of Power System, and was many of variation but, it is using. The present is using Digital type distance relay for 765kV transmission line protection. If impedance value of transmission line were to value lower than setting, this would be operating and relay setting rule is for 85% into Zone 1 self section, and Zone 2 is a 125%, Zone 3 is a 225%. Which's $15{\sim}25%$ include current transformer error 5%, potential transformer 5%, relay calculation error 5% and margin factor from the field experience. This paper is discussed transmission protective relay and relay setting rule of high voltage power system and we verify the correctness relay setting rule with distance relay using Matlab simulation.

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Design and Evaluation of a Protection Relay for a Wind Generator Based on the Positive- and Negative-Sequence Fault Components

  • Zheng, Taiying;Cha, Seung-Tae;Kim, Yeon-Hee;Crossley, Peter A.;Lee, Sang Ho;Kang, Yong Cheol
    • Journal of Electrical Engineering and Technology
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    • 제8권5호
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    • pp.1029-1039
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    • 2013
  • To avoid undesirable disconnection of healthy wind generators (WGs) or a wind power plant, a WG protection relay should discriminate among faults, so that it can operate instantaneously for WG, connected feeder or connection bus faults, it can operate after a delay for inter-tie or grid faults, and it can avoid operating for parallel WG or adjacent feeder faults. A WG protection relay based on the positive- and negative-sequence fault components is proposed in the paper. At stage 1, the proposed relay uses the magnitude of the positive-sequence component in the fault current to distinguish faults requiring non-operation response from those requiring instantaneous or delayed operation responses. At stage 2, the fault type is first determined using the relationships between the positive- and negative-sequence fault components. Then, the relay differentiates between instantaneous operation and delayed operation based on the magnitude of the positive-sequence fault component. Various fault scenarios involving changes in position and type of fault and faulted phases are used to verify the performance of the relay. This paper concludes by implementing the relay on a hardware platform based on a digital signal processor. Results indicate that the relay can successfully distinguish the need for instantaneous, delayed, or non-operation.

A Derivation of Comprehensive Protection Ratio and Its Applications for Microwave Relay System Networks

  • Suh Kyoung-Whoan
    • Journal of electromagnetic engineering and science
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    • 제6권2호
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    • pp.103-109
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    • 2006
  • This paper suggests an efficient and comprehensive algorithm of the protection ratio derivation and illustrates some calculated results applicable to the initial planning of frequency coordination in the fixed wireless access networks. The net filter discrimination associated with Tx spectrum mask and overall Rx filter characteristic has been also examined to show the effect of the adjacent channel interference. The calculations for co-channel and adjacent channel protection ratios are performed for the current microwave frequency band of 6.7 GHz including Tx spectrum mask and Rx filter response. According to results, fade margin and co-channel protection ratio reveal 41.4 and 75.2 dB, respectively, for 64-QAM and 60 km at BER $10^{-6}$. It is shown that the net filter discrimination with 40 MHz channel bandwidth provides 28.9 dB at the first adjacent channel, which yields 46.3 dB of adjacent channel protection ratio. In addition, the protection ratio of 38 GHz radio relay system is also reviewed for millimeter wave band applications. The proposed method gives some advantages of an easy and systematic extension for protection ratio calculation and is also applied to frequency coordination in fixed millimeter wave networks.

오차를 고려한 765kV 변압기 보호 계전 정정룰 고찰 (Investigation into Transformer Protective Relay Setting Rule Considering Error Ratio)

  • 배영준;이승재;최면송;강상희;김상태;최정이;정창현;유영식;조범섭
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2002년도 하계학술대회 논문집 A
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    • pp.229-231
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    • 2002
  • The digital current differential relaying scheme is widely used for primary protection of 765(kV) power transformer. The current differential relay pickup the internal fault at the threshold which is set at 30% of rating current. Margin of 30% include current transformer error 5%, relay error 5%, on load tap changer error 7% and margin factor 140% obtained from the field experience. In this paper transformer protection relay and relay setting rule of high voltage power system are discussed. And we verify the correctness of relay setting rule with current differential relay using Matlab simulation.

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디지털 보호계전기의 신뢰도 분석 (Reliability Prediction of Digital Protection Relay)

  • 송인준;안용호;양귀장;전광식
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2008년도 제39회 하계학술대회
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    • pp.377-378
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    • 2008
  • 한전에서는 계통보호 설비의 신뢰도 확보를 위해 디지털 보호설비 사용을 확대하고 있으며, 이에 따른 합리적인 보호설비 교체기준을 설정하려고 한다. 본 논문에서는 디지털 보호계전기의 교체기준 설정을 위해 디지털 보호 계전기(Digital Distance Relay)와 구성모듈에 대한 고장률(Failure rate)과 평균수명(Mean Time between Failures, MTBF), 그리고 시간에 따른 신뢰도를 분석하였다. 수명예측방법은 MIL-HDBK-217F, Notice 2의 부품스트레스분석방법(Part Stress Analysis Method) 사용하였다.

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적응보호를 위한 계층적 시스템의 기본구조 (Basic Structure for Hierarchical Adaptive Protection System)

  • 이승재;김기화;오정환;임동진
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 하계학술대회 논문집 B
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    • pp.584-587
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    • 1995
  • Recent development in the digital relay technology has introduced the adaptive relaying system which adopts the relays to the current operating states. This paper proposes the hierarchical digital protection system whose design has been based on 154 kV S/S. Applying the newest communication networking, the system provides the new protection capabilities improving the system reliability and speed.

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디지털 거리계전기의 Zone 설정에 관한 연구 (A Study on the Zone Setting of Digital Distance Relay)

  • 이재규;정창호;정병태;안복신;김석일
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1998년도 하계학술대회 논문집 C
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    • pp.946-948
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    • 1998
  • The distance relay is very important for transmission line protection. A quadrilateral zone shape is used mainly for a modern digital distance relay. The shape of quadrilateral is vendor specific. At the stage of design, the shape is determined considering all possible types of faults and diverse configurations of system. Also this type relay must be designed to avoid the operation by a sound phase at single-Phase-to-ground fault, by a sound phase at two-phase-to-ground fault. The effect of a source impedance and a load impedance is another important factor to design. In this paper, a reliable zone shape which is appropriate for the KEPCO's transmission system is provided.

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