• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.634-636
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• 1995

This paper presents a new distance relay modeling techniques which avoids unnecessary computational procedure. A general-purpose simulation language, called MODELS, has been added to the software ATP(Alternative Transients Program) providing a new option to perform numerical and logical manipulations of variables of an electrical system. This language has been designed to replace the previous option TACS (Transient Analysis of Control Systems) which permits to simulate a control system in conjunction with a large power network. One purpose of this study is to build a structure for modeling of digital distance relays within EMTP MODELS. Contrary to the traditional methods, the new method using MODELS reduce the number of simulation steps in modeling the distance relay.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.1
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• pp.38-44
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• 2001

For double-circuit transmission line systems, an accurate digital distance relaying algorithm immune to the reactance effect is proposed. The apparent impedance calculated by the distance relay is influenced by the combined reactance effect of the fault resistance and the load current as well as the mutual coupling effect caused by the zero-sequence current of the adjacent parallel circuit. To compensate the magnitude and phase of the estimated impedance, this algorithm uses phase angle difference between the zero(positive) sequence of the both side of the system seperated by the fault point. The impedance measuring algorithm presented used a current distribution factor to compensate mutual coupling effect instead of the collected zero-sequence current of the adjacent parallel circuit.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.625-626
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• 2007

This study is on the protection system of Korean power system applying superconducting power devices. We investigates firstly protection systems of Korean power system and then do a basic study on the impact of relay systems in the power system with superconducting devices. For the more reliable result, we will carry out relay operation tests in the power system applying superconducting facilities using RTDS(Real Time Digital Simulator) in the future.

• Progress in Superconductivity and Cryogenics
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• v.10 no.3
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• pp.9-13
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• 2008

It is very important to study the protective relaying system from the viewpoint of technical analysis to apply superconducting power devices to real power systems. In this paper, we developed Superconducting Fault Current Limiter (SFCL) analysis model using Real Time Digital Simulator(RTDS) for protective relay tests in power system with SFCLs. The RTDS model has the operation mechanism of a real SFCL system.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.13 no.8
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• pp.1491-1496
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• 2009

This paper presents an digital based input/output interface circuit for controlling and monitoring the Diesel Engine Generator for emergency. In order to monitor and control of the Emergency Diesel Engine Generator, controlling and monitoring circuits need 5 analog input channels, 2 pick-up coil measuring circuits, 10 digital input channels containing Broken Wire Detect function, and 7 relay control signal output channels. This system performs signal processing of input signal taking advantage of simple filter circuit, photo-coupler and comparator circuit at analog input parts, and output signals for main relay is designed acting by double control, so it prevents malfunction completely. And it improves accuracy of speed input signal by applying digital circuit that processes rick-up coil signal.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2009.05a
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• pp.547-550
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• 2009

This paper presents a digital based input/output interface circuit for controlling and monitoring the Diesel Engine Generator for Emergency. In order to monitor and control of the Emergency Diesel Engine Generator, controlling and monitoring circuits need 5 analog input channels, 2 pick-up coil measuring circuits, 10 digital input channels containing Broken Wire Detect function, and 7 relay control signal output channels. This system performs signal processing of input signal taking advantage of simple filter circuit, photo-coupler and comparator circuit at analog input parts, and output signals for main relay is designed acting by double control, so it prevents malfunction completely. And it improves accuracy of speed input signal by applying digital circuit that processes pick-up coil signal.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1793-1795
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• 2004

지금까지 변전소나 개폐소에서 전류, 전압을 계측하는 수단으로서 주로 철심과 권선으로 구성되어진 변류기(CT), 계기용 변압기(PT, PD)가 사용되어 왔다 최근, 2차측의 계측기나 보호 Relay의 Digital화가 진전되어, 또한 이것을 Digital Network으로 종합한 Intelligent 변전소의 구축이 검토되어짐에 따라 Digital Network에 대응한 신형 CT, VD가 요구되어 지고 있다. 상기와 같은 요구로 인해 당사에서는 CT는 검출부에 Rogowski Coil을 적용하며 그 후단에 적분기를 설치하였으면, VD는 검출부에 중간 전극을 이용해서 분압하는 방식인 Capacitive Voltage Divider를 사용하고 증폭기를 삽입하여, 각각 요구되는 전압 신호를 얻었다. 이러한 신형 CT/VD의 적용으로 종래의 CT/PT가 차지하는 공간이 필요 없게 되어 컴팩트한 GIS의 구조가 능하게 되어 있다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1191-1192
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• 2011

We released new triple redundant digital excitation system with real time generator-turbine simulator. One of its great merits is the real time generator-turbine simulator when it was compared with the other products. If excitation system is tripped by unexpected faults, Maintenance man can do easily performance test of digital excitation control board, sequence relay and thyristor switching device of phase controlled rectifier without manufacturer's support. For the verification of this system, It was tested with an actual excitation system implemented on 5kVA M-G Set. After finishing the tests, the trial product will be installed and operated at a 500MW thermal power plant.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.456-457
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• 2006

We have carried out the construction of the 154kV intelligent substation with KEPRI. The Intelligent substation is built in Gochang testing facility of KEPCO and consists of electronic instruments for GIS(gas insulated switchgear), digital control panel, remote monitoring and diagnosis system, and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are introduced compared with the instrument transformer of conventional type. Digital control Panel(DCP) replaces the LCP(local control panel) which is drived for mechanical operation. For the monitoring of the condition of GIS and TR, various sensors are used. In this Paper, we mention the synopsis and report the progress state of project.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.33-35
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• 2005

We perform intelligent substation construction of 154kV class with KEPRI. The intelligent substation is build in Gochang 765kV testing facility and consists of electronic instruments, digital control panel, remote monitoring and diagnosis system and digital relay system. Rogowski coil type CT(RCT) and capacitive voltage divider(CVD) are applicable for instrument transformer of conventional type. Digital control panel(DCP) replaces local panel which is drived by mechanical operation. For monitoring condition of GIS and TR, various sensors are used. In this paper, we report the synopsis and the progress state of project.