• 조명전기설비학회논문지
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• 제22권5호
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• pp.13-20
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• 2008

과거에는 순간전압강하(Sag)나 고조파(Harmonics)와 같은 순간전력품질 문제가 부하에 큰 영향을 미치지 않았으나, 최근 컴퓨터와 같은 마이크로 프로세서를 이용하는 민감부하의 사용 증가로 인하여 전력품질에 대한 관심이 고조되고 있다. 이에 따라 현재까지 영구정전(Sustained Interruption)에 초점을 맞추고 일부 순간정전(Momentary Interruption)을 포함하여 진행되어 온 배전계통 신뢰도 연구 분야는 새로운 전환점을 맞이하고 있다. 즉, 전력품질문제로 인하여 많은 민감기기들이 트립(Trip)되어 신뢰도 비용이 발생하기 때문에, 전력품질을 고려하지 않은 신뢰도 비용평가는 그 정확도가 떨어질 수밖에 없는 실정에 있다. 본 논문에서는 배전계통 사고 시 이 사고를 제거하기 위해 사용된 리클로져에 의해 발생하는 순간전압강하를 고려하였다. 기존의 영구정전에 의한 신뢰도 비용과 순간전압강하에 의해 트립되는 기기들의 신뢰도 비용을 포함하는 개선된 배전계통 신뢰도 비용 평가 기법을 제안하였다.

• 전기학회논문지
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• 제58권7호
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• pp.1270-1275
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• 2009

The structure of a power distribution system will change in a loop configuration such as in the case of a smart grid. If power distribution system changes radial to loop form, the structure may have to be changed significantly. Therefore, we analyzed the reliability indices and calculated a CIC(Customer Interruption Cost) for the loop power distribution system. The power distribution system reliability depends on the protection scheme. This study is applied to the current protection scheme method and is compared with each model. When the CIC was evaluated, most studies performed calculations only for sustained interruptions. However, in actuality, momentary interruption frequencies occurred more than sustain interruptions. Thus, it is occurred the CIC additively. Therefore, we evaluated a CIC including momentary interruption, for each model, and then compared with MAIFI(Momentary Average Interruption Frequency Index)

• 한국전자통신학회논문지
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• 제16권2호
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• pp.293-300
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• 2021

본 연구에서는 SCDF를 사용하여 전력공급의 가치를 산정하고, 부하점별 중요도를 다면적인 평가를 하는 방법을 제시한다. 이의 방법으로 지속정전, 순간정전, 전압 Sag/Swell에 대응할 수 있는 SCDF를 제공하고, 이 SCDF를 사용하여 정전과 관련하여 어느 부하점에 어느 정도의 비용이 발생하는지를 계산하였으며, 이들 비용을 다면평가를 통해 어느 부분이 어느정도 취약한지를 평가하고 어느 부분의 확장이 필요한 지를 수치적으로 설명할 수 있도록 하였다. 본 연구를 우리나라의 실배전계통에 적용하여 평가하고 유용성을 검증하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.525-527
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• 2000

This paper presents a reliability evaluation method for considering the voltage quality. The proposed evaluation methods are contained the sustained interruption, momentary interruption and voltage sag. For momentary interruption, evaluation indexes are divided the duration based index and the interruption cost index. For voltage sag, the final result of evaluation method represents the magnitude for customers' risk due to the voltage sag. The proposed method is tested using the RBTS model and a reliability data in KEPCO's system.

• 대한전기학회논문지:전력기술부문A
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• 제54권4호
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• pp.177-184
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• 2005

This paper proposes a improved investment priority decision method of the facilities considering the reliability of distribution networks. The proposed method decides a investment order of the facilities combining, by fuzzy rules, the investment priority decision of KEPCO and the priority decision considering reliability evaluation indices. Where reliability evaluation indices are SAIFI(System Average Interruption Frequency Index) and SAIDI(System Average Interruption Duration Index), as referred to evaluation index for sustained interruption. The reliability analysis method of distribution networks applied in this paper utilizes analytic method, where the used reliability data is historical data of KEPCO. Particularly, we assumed that the failure rate increased as the equipment ages. To verify the performance of the proposed method, we applied it with the planned projects to reinforce the weak facility electrical facilities in KEPCO in 2004. The evaluation result showed that, under a limited budget, the reliability of the KEPCO in the Busan region using the proposed method can be enhanced than using the conventional KEPCO's method. Therefore, the results verify the proposed method can be efficiently used in the actual priorities method for investing the electrical facilities.

• 한국전기전자재료학회논문지
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• 제17권6호
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• pp.673-677
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• 2004

We present the basic properties of a superconductive fuse (SF) based on YBCO/Au films. The SF consists of YBCO stripes covered with Au layers for current shunt. The fault current was limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enabled the SF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption. Under the source voltage of 100 $V_{rms}$, the longer the duration time of fault current was, the shorter its discharge time was. The duration time of fault current and its discharge time were reduced by increased voltages in the range of 200 - 300 $V_{rms}$. We thought that this was because the quench propagation was limited by local melting generated with higher voltage.age.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2000년도 하계학술대회 논문집 A
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• pp.252-254
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• 2000

For many years, electric utility has used sustained interruption rates as a reliability index. Today, however, many electricity consumers are adversely affected by more subtle voltage disturbances such as harmonic distortion. This paper deals with observations of events that occur in the Dimmer circuits and phase control which could affect harmonics problem to the commercial power system. In order to reduce the effect of harmonics and design filters, Solid State Relay Dimmer(SCRs or TRIACs) and Noise Filter are described, and the effects of harmonics is also analyzed. IGBT Dimmer which is appropriate method to reduce harmonics and improve efficiency is introduced.

• Journal of Chest Surgery
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• 제23권6호
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• pp.1263-1269
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• 1990

Two patients with uncorrectable cyanotic cardiac anomalies underwent total cavopulmonary shunt[modified Fontan operation]. Case I was a 14 years old male with dyspnea and cyanosis after birth. Aortogram showed TGA combined with overriding of aorta, pulmonary stenosis, complete atrioventricular septal defect, interruption of inferior vena cava, and situs inversus totalis. We had performed total cavopulmonary shunt using with 16 mm Gortex Graft in single atrium to bypass the hepatic vein to pulmonary artery. Postoperatively, patient sustained low PaCO2 and low cardiac output and then expired at 19th postoperative day. The cause of death of the patient would be low cardiac output. Case II was a 6 years old female with dyspnea and cyanosis after birth. Aortogram showed tricuspid atresia[Type IIb], transposition of great arteries, atrial septal defect, ventricular septal defect and pulmonary stenosis, We had performed total cavo-pulmonary shunt using intraatrial baffle[tunnel] with Goretex patch. The postoperative course of this patient was good without event.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전기기기 및 에너지변환시스템부문
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• pp.67-68
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• 2001

We present the basic properties of a superconductive current limiting fuse (SCLF) based on YBCO/Au films. The SCLF consists of meander type YBCO stripes covered with an Au layer for current shunt. The fault current was first limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enables the SCLF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2004년도 춘계학술대회 논문집
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• pp.318-320
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• 2004

We investigated the basic properties of a superconductive current limiting fuse (SCLF) based on YBCO/Au films. The SCLF consists of meander type YBCO stripes covered with an Au layer for current shunt. The fault current was first limited to a designed value in less than 0.4 msec by resistance development in YBCO/Au upon quenching. This enables the SCLF to transfer small fault power and the suppressed current was sustained for more than 0.5 msec while Au layer melting and arcing. The arcing time was less than 2.5 msec, that is short enough to do self-interruption.