• Proceedings of the KIEE Conference
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• 1996.07c
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• pp.1813-1815
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• 1996

With the three dimensional magnetic field measuring system dealt with in this paper, accurate measurements and analyses of ELF magnetic fields in the vicinity of UHV overhead transmission lines and substations have been conducted. For the field measurements multiturn loop-type sensors have been developed with special consideration of taking lower frequency and spatial components without any distortion. So the measuring system has the frequency bandwidth of 8[Hz] to about 53[kHz] and the response sensitivity of $9.88[mV/{\mu}T]$ in average. A brief description of design rules of the measuring system and measurement procedures is given. The actual surrey near 154 and 345[kV] overhead transmission lines and power subststions was carried out and analyzed. It may be inferred from these results that the maximum magnetic field intensities under typical UHV overhead transmission lines do not exceed $20[{\mu}T]$ so that the field measurements satisfy sufficiently all limits or guidelines that various authorized international institutes recommend.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.385-387
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• 2003

전력계통의 증가에 따라 일부 계통에서 지락고장 전류가 2010년이후 차단기 정격전류인 40[kA]를 초과할 것으로 예상된다. 이에 대한 대책으로 345kV 변압기의 중성점의 부동(Floating) 운전을 위하여 PSS/E를 이용하여 실제의 발변전소의 모델을 설정하고 EMTP를 이용하여 지락고장 발생시 건전상의 전위상승, 중성점 전위상승, 부동운전 가능 대수, 변압기 중정점 NGR 설치 효과 및 적정 임피던스 산출, 변압기 중성점 피뢰기 설치 효과 및 적정 정격 산출등을 검토하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.368-370
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• 2005

Due to the tendency towards large capacity and complexity of power system, an enhancement of power system equipment make a system impedance to be low in power system. Generally if an equivalent impedance of system becomes lower, a system stability will be better. But the fault current becomes very larger. The 345kV ultra-high voltage system will use current limit reactors(CLR) in a transmission line or a bus in substation to limit the magnitude of fault current. The CLR makes a significant contribution to the severity of the transient recovery voltage(TRV) experienced by feeder and bus circuit breakers on clearing feeder faults. Based on the conclusions of an investigation of actual circuit breaker failures while performing this duty, the mitigation of the transient recovery voltage associated with the reactors is described. Therefore in this article we simulated the TRV by EMTP at Bus Terminal Fault.

• Proceedings of the KIEE Conference
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• 2009.07a
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• pp.60_61
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• 2009

최근 국내에서 345kV GIL(Gas Insulated Transmission Lines) 시스템의 실 계통 도입이 검토되고 있다. 현재까지 GIL은 원자력 발전소에서 주변압기로부터 스위치 야드까지 1km 미만의 거리에 소규모로 설치되어 운영되고 있다. 하지만 향후 본격적으로 GIL 시스템이 도입된다면 발전소 구내뿐만 아니라 수 km 이상 되는 송전급 선로에도 적용될 것이 예상된다. 현재 GIL의 시스(외함)는 100~120m 정도마다 접지를 하는 직접접지 형태를 취하고 있으나 시스에 흐르는 순환전류가 부하전류의 97% 이상 된다. 따라서 이에 따른 손실이 많이 발생되고 있어 도체에 흘릴 수 있는 허용전류 값이 감소하게 된다. 본 논문에서는 GIL 시스템에 크로스본드 접지방식을 적용하였을 때 시스 순환전류 감소 효과에 대해서 검토하고, 아울러 뇌써지나 스위칭 써지에 의한 절연통의 열화 등에 대비하기 위하여 절연통보호장치의 설치 방안에 대해서 검토하였다.

• Proceedings of the KIEE Conference
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• 1996.07b
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• pp.883-886
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• 1996

Instead of point-to-point hard wiring between substation yard equipments and SCADA RTU(Remote Terminal Unit), fibre optic cable will be used in the portion between Local Units and Central Unit in the future KEPCO 765kV substation. The connections between substation yard equipments and nearby Local Unit remain the same hard wiring. The new fibre optic system will provide security especially during ground faults and is immune to electrical noise. A prototype system will be manufactured and installed in the existing 154kV Yeosan Substation by the end of July this year and operated for one year. By incorporating the operation experiences acquired in the system, an improved system will be commercially applied to 765kV Shin-An-Seong Substation where 345kV GIS will be installed initially and act as the switching station in the year 1998. The system is composed of one Central Unit and several Local Units. The Central Unit is composed of two workstation level computers, one is in operation and the other backup, and a Communication Control Unit. The Local Unit uses the existing SCADA RTU technology and takes the form of a distributed one. Between the Communication Control Unit and Local Units, the fibre optic system with star-coupler is used.

• Proceedings of the KIEE Conference
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• 1999.11b
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• pp.312-314
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• 1999

한전에서는 1996년 제주-해남간 HVDC 설치에 이어, 1999년 서대구 S/S에 SVC를 설치하였다. 이와 관련하여 본 논문에서는 한전계통에 최초로 설치한 서대구 S/S의 SVC설비운용과 관련하여 SVC의 이론 및 제어기법과 관련된 일반이론을 소개하고, 설치된 SVC의 기기구성방식 및 특성, 제어특성, 기기사양 등에 대해 간략하게 소개하고자 한다. 서대구 SVC는 345kV/13.5kV, 100MVA급으로서 TCR 및 TSC방식의 하이브리드 방식으로 되어 있다.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1628-1632
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• 1994

KEPCO is now promoting the new project of upgrading its highest system voltage from 345kV to 765kV. The main reason of this project is an insurance of bulk power transmission from power complexes at coast to power demand center at Kyoung-In area. The new system needs a careful approach to basic design to secure its reliability and to reduce the increase of investment cost. So, We introduced the basic philosophy of insulation design in spring meeting of this transaction. This paper, after preceding paper, deals with the insulation design example for 765kV transmission lines.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.87-89
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• 2005

This paper proposes new series and parallel Sin+Cos PSS(power system stabilizer) for the purpose to improve the existing PSS1A's performance. The purpose of PSS is used to enhance damping of power system oscillations through injection of auxiliary signal for an excitation control terminal. The Proposed series and Parallel Sin+Cos PSS is connected adding the Sin+Cos terms additionally with serial and with parallel connection in a conventional PSS1A. The proposed controller is aim to considering of a damping of oscillation when it changes parameter fluctuations or operational load variations in a power system. The object of electric power system is KEPCO system and the voltage of power transmission line is a 154kV and a 345kV. The PSCAD/EMTDC package is used to authorize the effect of the proposed controller. Simulations were shown by and compared with the waveforms for frequency, voltage and electric power.

• Proceedings of the KIEE Conference
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• 1990.11a
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• pp.166-169
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• 1990

The purpose of the circuit breaker on power system is to disconnect the faulty part from the system and to maintain the integrity of the system. With switching overvoltages are generated. When the system voltages become higher, switching overvoltage is important factor in insulation co-ordination. Since the no-load reclosing overvoltage with inductive source is severe, this paper deals with the reclosing overvoltage and the effect of closing resistor. This reclosing overvoltage of 27-bus model system with and without closing resistor is analyzed by using EMTP (Electro-Magnetic Transients Program) for both deterministic and Stochastic model.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.371-373
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• 2005

An enhancement for a transmission and substation equipment in power system make the system impedance to be lower. In principle, if the system impedance become low, system stability will be better, but the fault current become very higher. It is a very big problem for CB operating. As a fact of CB operating performance, high amplitude of the fault current may cause CB operation failure because of exceeding standard value in TRV. So we simulated TRV by using the EMTP. Generally there are two types of TRV in actual power system. One is short line fault, the other is bus terminal fault. In this paper, we simulated the TRv at short line fault as installed current limit reactors to reduce fault current in 345kV ultra-high voltage system. Short line fault is caused from single line fault in transmission line.