• The Transactions of the Korean Institute of Electrical Engineers P
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• v.55 no.1
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• pp.6-12
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• 2006

A popular method used by primary protection for power transformer is current ratio differential relaying (RDR) with 2nd harmonic restraints. In modern power transformer due to the use of low-loss amorphous material, the 2nd harmonic component during inrush is significantly reduced. The higher the capacitance of the high voltage status and underground distribution, the more the differential current includes the 2nd harmonic component during internal fault. Thus the conventional method may not operate properly. This paper proposes an advanced relaying algorithm and the prototype IED hardware design and it's real-time experimental results. To evaluate performance of the proposed algorithm, the study is well constructed power system model including power transformer utilizing the EMTP software and the testing is made through simulation of various cases. The proposed relaying that is well constructed using DSP chip and microprocessor etc. has been developed and the prototype IED has been verified through on-line testing. The results show that an advanced relaying based prototype IED never mis-operated and correctly identified all the faults and that inrushes that are applied.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.766-767
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• 2011

전력 IT 추세에 따라 IED(Intelligent Electronic Device)에서 다양한 기능이 요구되고 있으며, 따라서 이를 구현하기 위한 시스템도 복잡화되어 가고 있다. 또한 IED 내부에서에서 처리하여야 하는 데이터양이 대폭 증가하고 있으며 고속의 처리 속도를 요구하고 있기 때문에 산업용 시스템 버스의 도입 필요성이 제기되고 있다. 산업용 시스템 버스는 오랜 적용기간을 통해 그 신뢰성을 검증받았으며, 호환성이 뛰어나 H/W 플랫폼으로서의 가치가 있다. IED의 경우와 같이 다수 개의 CPU가 요구되는 시스템에서 CPU간 H/W적인 데이터 인터페이스 방식을 어떻게 선정하는지는 매우 중요하며 본 논문에서는 CompactPCI 기반의 최신 기술인 CompactPCI Plus IO와 Serial 기술에 대하여 살펴보고, IED에서 사용되는 기존의 메모리 공유방식이나 저속 시리얼 방식 대신 상기 CompactPCI 기반의 기술을 적용하는 방안에 대하여 검토해 보기로 한다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.53-54
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• 2015

기존의 IEC 61850 표준 적용 국내 디지털변전소는 Station 레벨에 한정되어 구축되어 왔다. 향후 구축될 Process 레벨을 포함한 풀(Full) 디지털 변전소 디지털화는 디지털변전소 운전에 있어 중요하고 긴급한 신호인 Process bus를 통한 SV와 GOOSE신호의 전송으로 이루어지고 있다. Process bus를 활용한 배전선로 보호용 통합 IED는 GIS 등 변전소 전력설비로부터 전압과 전류 값을 MU(Merging Unit)를 통해 공급받아 각 구간의 Bay 혹은 Bank단위로 통합적인 보호 기능을 수행하고, 주 IED와 예비 IED가 서로의 상태를 상호 감시하여 보호기능의 이중화를 이루어야 하고, Sampled Value를 처리하기 위한 정밀한 시각동기화 기능을 갖추어야 한다. 만약, Process bus 시스템의 문제로 인해, 지연과 손실이 발생한다면 변전소 보호 제어에 영향을 줄 수 있으므로 Process bus를 디지털변전소에 적용하기 위해서는 Process bus 기반의 네트워크시스템에 연결된 MU와 IED가 송수신하는 SV와 GOOSE를 손실과 지연없이 전송할 수 있는지를 분석해야 한다. 본 연구에서는 디지털변전소 네트워크 시뮬레이션 시험을 통해, 배전선로용 통합 IED의 성능검증을 위해 Process bus 네트워크 시스템을 설계하고 시뮬레이션 시험을 수행하여 이를 통해 향후 국내의 Process bus 디지털변전시스템 구축을 위한 효과적인 네트워크 시스템 설계방법을 제시하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.8 no.5
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• pp.381-388
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• 2003

In this paper, the IED(Intelligent Electronic Devices) with the consideration of harmonic problems is discussed, With significant development of power electronics technology, the proliferation of a nonlinear load has more deteriorated power quality, As continuous harmonic current makes for a shortening lifetime, overheat and abnormal operation, it should be considered to improve these problems. However, the conventional digital protective relay which eliminates harmonic elements with orthogonal filter has a defect on actually implementation. The prototype IED is constructed with Digital Signal Processor(TMS320C32) and Complex Programmable Logic Device. According to the experiment and simulation results, it is proved that the proposed system has good performance of measuring harmonic factors and protecting electrical equipment.

• Proceedings of the KIEE Conference
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• 2006.11a
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• pp.6-8
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• 2006

변전소 자동화 시스템에서 IED(Intelligent Electronic Device)들 간의 효과적인 통신을 위해 표준프로토콜인 IEC-61850이 제시되면서 이를 구현하고 응용하기 위한 관심이 높아지고 있다. 본 논문은 IEC-61850 표준규격을 분석하여 제시된, 거리 계전 IED 모델을 이용해 송전선 보호 IED를 구현하였다. 통신기능 구현은 리눅스 커널 2.6 기반의 통신보드를 사용하였고 계전 알고리즘의 수행은 TMS320C32 기반의 DSP(Digital Signal Processor) 보드를 사용하였다. 보드간 통신은 CAN(Cont roller Area Network) 통신으로 이루어 졌으며 사례연구를 위해 RTDS(Real Time Digital Power System Simulator)를 이용하여 입력신호를 생성하였다. 구성된 시스템의 검증을 위해 거리계전기에서 후비보호 시 발생할 수 있는 문제점을 시뮬레이션 하였다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.1
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• pp.23-28
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• 2012

The market of domestic Power Plant Generator Protection and Control System (GPCS) is narrow and required the high reliability, and technology. So, it is still operated as turn-key. In recent years, digital relays has evolved into IED can perform the control and monitoring functions without central monitoring based on IEC61850 international standards communications, and attention for advancement of smart grid and ECMS has been increased in South Korea. The increasing attention on multi-function IED, DGPS(digital generator protection system), for internal fault protection of large generator results in starting a national project in South Korea, the IED prototype development for next-generation power units. The voltage restrained overcurrent relay have been used as back-up overcurrent protection for generators. In this paper, voltage restrained overcurrent relay is one of the back-up protective factors in generator protection IED was presented. For evaluation performance of the voltage restrained overcurrent relay, the data of ATPDraw5.7p4 modeling was used.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.561-562
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• 2015

2013년 이후, 한국전력공사에서는 신규건설 변전소로 디지털변전소(Digital Substation)를 건설하고 있다. 디지털변전소 내에는 서버(IED, 지능형전자장치), 클라이언트(상위운영시스템)가 필수요소들이며, 이 둘은 서로 서버/클라이언트 통신 서비스를 수행하고 있고 IEC61850 기반으로 하고 있다. 바뀐 정책과 프로토콜 때문에 사용되는 기기 역시 기존 디지털 보호 계전기에서 IED로 성능이 변화하였고, 기존에 수행하던 보호성능검증 방법인 동특성시험 역시 IEC61850 기반 통신서비스 성능도 함께 보아야 한다는 관점에서 본 연구가 시작되었다. 본 논문에서는 RTDS를 이용한 IEC 61850 기반 IED 동특성 시험 성능검증 방법에 대하여 살펴보고, 그 결과를 알아보고자 한다.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.55 no.9
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• pp.376-383
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• 2006

In this paper, autonomous information exchange methodology is studied between IEDs using SOAP protocol based on XML and PtP communication to archive the safety and reliability of large-scale system operation. The SOAP protocol has the advantages in the independency Problem for operating systems, using language, platforms and the security problem because it is XML-based RPC protocol. Inference-based solution of the IED is designed as rule-based solution so that the IED internal status, the system status or the faulted zone can be inferred autonomously using the internal data as well as information data obtained from free information exchange among other IEDS, Also, it is designed so that the inference results and the operation information are transmitted to the above SCADA system, and determined autonomously whether the commands from the SCADA are executed or not. Finally, The inference-based solution of IED and information exchange system among IEDS is implemented using MS Visual C++ MFC, MS SOAP and MS XML. Availability and accuracy of the proposed methodology and the design is verified from diversity simulation reviews for typical distribution substation.

• Journal of the Korean Society for Precision Engineering
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• v.25 no.7
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• pp.47-54
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• 2008

Recently, application of ceramics has increased gradually due to excellent mechanical properties. Si3n4-BN ceramic which is one of ceramics is very hard and has superior resistance against volatile temperature and wear. However, extremely high hardness of the $Si_3N_4-BN$ ceramic makes conventional machining very difficult. Therefore, the use of machinable ceramic has been in a poor because of difficult industrial processes in spite of many advantages. And so new technology being called IED(In-process electrolytic dressing) was introduced to solve this problem. The aim of this study is to determine the machining characteristics in terms of pressurized weight to the workpiece and the influence with h-BN content using IED lapping system. Also, Acoustic Emission (AE) is used for the monitoring of surface characteristics.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.3-5
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• 2008

Korea Electric Power Research Institute has being carried out an IEC 61580 based communication service test on domestic IED trial products developed related to power IT project. This paper describes IEC 61850-10 conformance test and testing items established by UCA international Users Group and this study is on the analysis of testing results from IED communication service with selected testing blocks, which consist of Basic association, Dataset, Reporting and GOOSE.