• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.407-414
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• 2010

This paper proposes a probability measure for the evaluation of relay performance from two aspects, namely, correct trip and no-unwanted trip. They are developed based on the relationship between relay settings and relay measurements, which follow a Gaussian probability model. The proposed method based on strict mathematical derivation is applied to protection capability evaluation of distance relays under various settings. Considering the specific attributes of each protection zone, the optimal settings are also determined accordingly. The protection capability could demonstrate clearly the relay performance under various settings and the optimal settings could provide good references for engineering applications.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.516-518
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• 2005

This paper presents a distance protection algorithm a lied to the linked line for interconnecting wind farm with the utility. The capacity of wind farm is lower than utility system and its fault current level is very low. When a high resistance fault occurs in the linked line, it is difficult to detect accurate fault distance because of reactance effect. By using the characteristic of equivalent source impedance of induction generator which is compensated by capacitor bank and characteristic of the capacity of wind farm, this paper proposes improved distance protection algorithm applied to the linked line. A series of PSCAD/EMTDC simulation results have shown effectiveness of the proposed algorithm.

• 대한안전경영과학회지
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• 제15권1호
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• pp.61-68
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• 2013

In the case of the fire to the exterior of the building through openings, the openings of the adjacent building are exposed to the risk of combustion expanding and factors that affect the combustion in the radiant heat and direct flame. Recent five years, fire of the adjacent building indicated that incidence of the 5,134(2.27%) among total 225,934 cases occurred The damage scale of fire expanded was lower than in a single building but casualties(5.46%) and property(25.0%) damage were higher. Therefore, this study provides to analyze the operating status for fire protection equipment of fire-preventing area in the Seoul and to apply measures to improve fire protection equipment according to narrow the distance between the building openings studied.

• 전기학회논문지P
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• 제63권4호
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• pp.322-326
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• 2014

Recently, the LOE(loss of excitation) incidents are occurred in domestic synchronous generator frequently, the synchronous generator protection system has been much attention for the LOE protection of the incidents that threats synchronous generators and power systems. This paper was showed the characteristics and practices of distance relay that widely used LOE protection relaying in generator. Firstly, the operating characteristics and the impedance locus for LOE of the generator protection were introduced. Even if the conventional simulation program is used for modeling, but it is difficult to implement a LOE modeling and simulation of synchronous generator. So, the LOE relay operation data collected from thermal power plant and nuclear power plant in real fields were analyzed. By reviewing the applications of GE Mho relays, the reliability of LOE for synchronous generator protection in domestic were improved.

• 대한전기학회논문지:전력기술부문A
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• 제54권12호
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• pp.573-579
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• 2005

Dynamic analysis of a transmission line which is compensated by a FACTS device such as STATCOM, SSSC and UPFC is carried out in this paper and the impacts on conventional line protection methods such as the DCPM (Differential Current Protection Method) and the DPM (Distance Protection Method) are reviewed. A refined DCRM is proposed to detect faults properly regardless of the FACTS operation. The proposed method is applied to a FACTS-compensated line with a variety of faults and is verified by simulation results. An adaptive DPM on a FACTS-compensated line was proposed previously in the literature. In order to emphasize the necessity of the modified DPM, the conventional DPM is applied to a FACTS-compensated system. Significant factors such as fault types, fault locations, and fault resistances as well as FACTS device types are considered for relaying setting.

• Journal of Electrical Engineering and Technology
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• 제1권4호
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• pp.423-426
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• 2006

Distance relays achieve selective tripping by measurement of all short circuit fault conditions inside set reaches. The direction of the fault, forward or reverse is commonly determined with a dedicated measurement to ensure selectivity under all conditions. For the direction decision (measurement) a number of alternatives are available. This paper describes a loop selective direction measurement and illustrates by means of a typical fault why this is superior to a non loop selective direction measurement such as that based on negative sequence quantities.

• 한국위성정보통신학회논문지
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• 제6권1호
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• pp.63-67
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• 2011

본 논문은 MCL(Minimum Coupling Loss)와 MC(Monte-Carlo) 방법을 이용하여 같은 주파수를 사용하는 ISM(Industrial Scientific Medical) 기기와 무선랜이 공간적으로 인접하여 사용될 경우의 간섭 영향 분석을 통해 ISM 기기로부터 무선랜을 보호하기 위한 보호 거리를 제시하였다. CISPR(International Special Committee on Radio Interference)에서 규정한 ISM 기기의 기준치를 간섭 파워로 설정하여 ISM 기기로부터 무선랜을 보호하기 위한 보호 거리를 산출하였다. 그 결과 최악의 상황을 고려한 MCL 분석시 105 m의 보호 거리와 통계적 간섭 확률을 바탕으로 한 MC 분석시 17 m의 보호 거리가 각각 산출되었다.

• 조명전기설비학회논문지
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• 제25권10호
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• pp.94-101
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• 2011

The proper installation of SPD and the evaluation of the SPD protection distance are basic steps for the effective protection measures of apparatus against surges within a structure. A novel method for installing SPD on the conventional distribution board without any modification was proposed and it's effectiveness was evaluated by experiments. Also, the transient overvoltage occurred across the power line from the SPD to the load was simulated with EMTP software to see how different the protection distances affecting the magnitude of the transient overvoltage. As evaluated, the effective protection method of apparatus against surges, coordinated SPD protection system is suggested as a proper measure to protect within the apartment.

• 한국통신학회논문지
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• 제37C권12호
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• pp.1211-1221
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• 2012

본 논문은 30 MHz 이하에서 동작하는 유도성 시스템과 전파통신 서비스의 공존을 위해서, 유도성 시스템의 간섭으로부터 전파통신 서비스를 보호하기 위한 보호 거리에 관한 것이다. 보호 거리 산출을 위해 유도성 시스템과 전파통신 서비스 간의 간섭 시나리오 모델을 제시하고 이를 기반으로 유도성 시스템의 방사 전력과 희생원의 허용 가능한 전계 강도를 비교하여 적용된 전파 모델에 따른 보호 거리를 산출하는 방법을 제안하였으며 이 방법을 적용한 RFID(Radio Frequency IDentification), PDP(Plasma Display Panel) TV의 간섭 분석을 통해, 30 MHz 이하의 전파통신 서비스 보호를 위한 보호 거리를 도출하였다. 제안한 방법은 2012년 6월 SG(Study Group) 1 회의에서 ISM 기기에 대한 결의 63과 관련된 ITU-R 권고서로 채택되어 유도성 시스템뿐만 아니라 무선전력 전송 및 전력선 통신 등에 의한 간섭 영향 분석에 활용될 전망이다.

• 조명전기설비학회논문지
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• 제27권7호
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• pp.89-94
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• 2013

This paper presents a method of simulating the protection effects of surge protective devices(SPDs) depending on the protective distance and types of input impedance of load to be protected. In order to analyze the protective performances of voltage-limiting type SPDs associated with the reflection and oscillation phenomena, the terminal voltage across load being protected and the residual voltage of SPDs were simulated by using EMTP model as functions of the protective distance and types of input impedance of loads. As a consequence, SPDs should be installed by taking into account the protective distance and input impedance of loads to achieve reliable protection of electrical and electronic equipment from lightning and switching surges. It is expected that the simulation method proposed in this paper could be practically used in design for installing SPDs in low-voltage distribution systems.