• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부A
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• pp.295-297
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• 1998

This paper shows characteristics of fault current division factor $S_f$, which is a ratio of earth- return current to total fault current, at a substation fed exclusively by power cables under unsymmetrical fault condition, such as single line-to-ground fault. In substation grounding system design, $S_f$ is a very important factor determining GPR, touch and step voltage at a substation under fault condition. In case of substations fed by overhead lines, 40-60% of $S_f$ has been typically used, although it is a very conservative value with no other network conditions considered. It is authors' hope that $S_f$ presented in this paper could hopefully be a basic reference in designing of substation grounding system, especially for a substation fed exclusively by power cables.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제51권4호
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• pp.210-220
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• 2002

We analysised the effect of harmonics on electric machines of substation power system barred on quantitatively measured harmonics and proposed the methods for prevention of harmonics through checking on transformer, rectifier and cable's capacities against harmonics with reference to KEPCO's electricity service standard. In order to analysis harmoninics of silicon rectifier that is power source in DC substation, computer simulations for a substation with TR of high voltage distribution switchboard are performed. Simulation results show that the total harmonic distortion factor becomes smaller for TR primary and receiving points in order rather than silicon rectifier which is harmonic generation source so that the harmonics generated frets each rectifier are outflowed to power supply and high voltage distribution switchboard The result of higher distortion factors of voltage and current for rectifier with 100% load than those with 50 % and 30% indicates that the waveform of voltage and current for the real substation power system at the office-going and the closing hours with heavy loads might be more distorted. As proposed methods for harmonic reduction, the conventional 6 pulse-type for substation is required to be replaced by 12 pulse-type for reduction of 5th and 7th harmonics. The active filter rather than the passive filter is more effective due to severe variance of rectifier loads, but the high cost is price to be paid. In view of installation area and costs, the use of 12 pulse-type transformer is desirable and then the parallel transformer and the rectifier within the substation must be replaced at the same time. Other substations with parallel feeder can use 6 pulse-type transformer.

• 전기학회논문지P
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• 제59권1호
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• pp.71-76
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• 2010

This paper is focused on implementing a real-time data acquisition system that checks power facility status by applying network based technology to Urban Transit substation power facilities and the results of its on-field tests. This system is composed of a sensor part, a measurement part, a transceiver part, a host computer, and a power source part. The system is designed to collect, save, analyze, and display the online state power facility AI (Analog Input). This system measures voltage and current from positive feeders and negative feeders where it is possible to check abnormalities of the substation‘s main power facilities. By monitoring abnormal data of the Urban Transit power facilities real-time and analyzing stored data, establishing procedures of optimized maintenance is possible.

• 한국전자통신학회논문지
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• 제14권6호
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• pp.1129-1138
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• 2019

변전소는 변전설비들이 제한된 장소에 집중되어 구조적으로 복잡하기 때문에 송전선로나 배전선로 상에서 고장발생 시 고장파급효과를 최소화하기 위한 보호협조 시스템을 설계하기가 쉽지 않다. 본 연구에서는 변전소 전력공급 신뢰성에 핵심적인 영향을 미치는 모선 방식과 보호협조 기초논리를 분석하였으며 EMTP-RV 기반으로 변전소 내부 및 외부 고장을 정확하게 검출하기 위한 변전소 보호협조 논리를 모델링하였다. 변전소 보호협조 기본 논리로서 변전소 내부 고장 검출을 위한 비율차동 보호계전 논리와 외부고장을 추론하기 위한 과부하 보호계전 논리가 모델링되었다. 끝으로, EMTP-RV를 이용하여 개발된 보호협조 논리 모델링을 기반으로 154kV 변전소를 모델링한 후, 수개의 고장모의를 통해 EMTP-RV 모델링 결과의 유효성을 확인하였다.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2000년도 추계학술대회 논문집
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• pp.696-703
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• 2000

This paper describes the capacity calculation of power supply system for light Rail Transit Three factors are considered for the design i.e. substation arrangements, line configuration and substation power capacity. In this study, we considered all of them for capacity calculation of power supply system for LRT. At first DC-fed-traction system is introduced on an outline, a characteristics of train and fed network, and design method of substation arrangements. Optimal design procedures are described, and program for capacity calculation of the system is presented. In addition, the computer simulated results are computed with the conventional simple calculation method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1-2
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• 2008

Korea Electric Power Research Institute has carried out verification of communication conformance on IEC 61850 based IEDs related to power IT project "Development of Prototype for Advanced Substation Automation System based on the Digital Control Technology". Owing to IEC 61850 international standard and digital substation automation system, IED testing process should be changed from the conventional way to the new way described in the paper. This paper describes IED testing procedures based on substation automation system using UML.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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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.

• 조명전기설비학회논문지
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• 제25권6호
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• pp.100-107
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• 2011

Since transmission and distribution neutral wires are connected with a substation grounding grid, it is very difficult to measure grounding resistance of isolated substation grounding grid after the substation is energized. It is impractical to isolate the grounding grid from other parallel connections such as distribution line neutrals and overhead ground wires for grounding resistance measurement only. In this paper, we proposed and demonstrated a novel measurement method of grounding resistance of isolated substation grounding grid. For this method, grounding current division factor and conventional FOP(Fall-Of-Potential) profiles were measured at power supplying 154[kV] substation. The obtained FOP profile was processed with the measured grounding current division factor to produce the grounding resistance of isolated grounding grid. Simulated FOP profile agreed well with the measured one showing the validity of the proposed method.

• 한국산업융합학회 논문집
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• 제14권3호
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• pp.121-125
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• 2011

EMTP-RV is the very powerful program to analyze the dynamic operation of the power system. To use this package in the large complex power system, it is very important to simplify the power system to simple equivalent network. In our study the 100 MVA STATCOM is placed at 345kV "MIGUM" which is the one of the 345kV substations of the Korean Electric Power System that is consist of more than 1000-bus. MIGUM substation is connected with 7 separated transmission lines to main Korean Electric power system. We developed a new method to simplify the network except the substation that we want to analysis. The power system outside the 345kV substation is modeled into the equivalent network. The loop network outside the substation can be modeled to simplified Thevenin equivalent network. The proposed method is applied to IEEE-14 Reliability Test System and the results shows the effectiveness of the method.

• 전기학회논문지
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• 제62권10호
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• pp.1458-1464
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• 2013

This paper proposed a new real time catenary impedance estimation technique using synchronized power data from the measured data of operating vehicle and substation for catenary protective relay and fault locator setting. This paper presented estimation equation of catenary impedance using synchronized power data between substation and vehicle of AT feeding system for the performance verification of the proposed technique. Also AC feeding system is modeled through power analysis program and performance was verified through simulation according to various load changes. We verified that average 2.38%(distance equivalent 23.8 m) error appeared between the proposed estimation equation of catenary impedance and power analysis program simulation output in no connection double track system between up track and down track. Furthermore, We confirmed that estimation error is bigger depending on the increasing the distance from substation and vehicle impedance using only using vehicle current when calculating vehicle impedance in connection double track system between up track and down track. But, We confirmed that the proposed technique estimated accurately catenary impedance regardless of vehicle impedance and distance from substation.