• Proceedings of the IEEK Conference
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• 2002.07a
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• pp.433-436
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• 2002

Most of electric distribution utilities have their reliability performance measured by reliability indices such as SAIFI and SAIDI to evaluate customer satisfaction. Adding protective devices in electrical distribution system can increase the system reliability by protecting public customers from local faults. In large-scale distribution system, it is difficult to determine the positions of these protective devices, which can efficiently protect customers within utilities' investment. In this paper, we propose an optimization technique to identify types and positions of protective devices to minimize SAIFI and SAIDI indices according to system requirement constraints.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.260-268
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• 2005

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

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.478-479
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• 2006

배전계통의 전기품질을 평가하기 위한 중요한 요소는 여러 가지가 있으며 그 대표적인 요소로 신뢰도 지수를 들 수 있다. 신뢰도 지수란 정전이 수용가에 미치는 영향을 정전시간과 정전수용가수로 표현한 지표로 공급에 대한 비신뢰도율을 나타낸다. IEEE 위원회는 다양한 지역을 벤치마킹하여 신뢰도 지수를 정의하였다. SAIFI와 SAIDI 등과 같이 공통적으로 사용 중인 지수가 있으며 지역의 특성에 따라 다양한 지수가 사용되고 있다. 이 논문에서는 IEEE에 정의된 전기품질 신뢰도 지수의 현황을 분석하고 국내에서 사용 중인 신뢰도 지수와 상호 비교하였다.

• Proceedings of the KIEE Conference
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• 2005.07a
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• pp.187-189
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• 2005

The asset management system for power distribution is necessary to make efficient use of distribution asset and to devise optimum investment plans. So we developed KDAMS(Korea Distribution Asset Management System) that is adopting reliability indexs, SAIFI and SAIDI, and operator's experiences. This paper presents functions of the system that is reliability management, failure rate management, establishment of optimum investment plan and so on. And it presents the of used algorithms to develop this system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.48 no.9
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• pp.1073-1080
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• 1999

Optimal routing of distribution networks can be attained by keeping the line power capacity limit to handle load requirements, acceptable voltage at customer loads, and the reliability indices such as SAIFI, SAIDI, CAIDI, and ASAI limits. This method is composed of optimal loss reduction and optimal reliability cost reduction. The former is solved relating to the conductor resistance of all alternative routes, and the latter is solved relating to the failure rate and duration of each alternative route. The routing considering optimal loss only and both optimal loss and optimal reliability cost are compared in this paper. The case studies with 10 and 24 bus distribution networks showed that reliability cost should be considered as well as loss reduction to achieve the optimal routing in the distribution networks.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.56 no.12
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• pp.2059-2064
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• 2007

This paper analyzed distribution network reliability related with the increment of outages and duration time according to distribution facilities increasing. KEPCO introduced distribution automation system in 1998 which could recognize outage section by remotely monitoring the fault current and reduce the blackout area by remotely controlling distribution switches. As the result of this outage time reduction using distribution automation system, the minimum distribution automation rate was fined out in this paper on the base of analyzing diverse data and how many switches were used in distribution system to improve distribution network reliability at the situation of distribution facilities increasing. This result can be used as the model that an overseas utility company applies distribution automation system in the future.

• Proceedings of the KIEE Conference
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• 1998.07c
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• pp.915-917
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• 1998

Optimal routing of distribution networks can be attained by keeping the line power capacity limit to handle load requirements, acceptable voltage at customer loads, and the reliability indices such as SAIFI, SAIDI, CAIDI, and ASAI limits. This method is composed of optimal loss reduction and optimal reliability cost reduction. The former is solved relating to the conductor resistance of all alternative routes, and the latter is solved relating to the failure rate and duration of each alternative route. The routing considering optimal loss only and both optimal loss and optimal reliability cost are compared in this paper. The results showed that reliability cost should be considered as well as loss reduction to achieve the optimal routing in the distribution networks.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.3
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• pp.61-66
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• 2002

Electric power distribution networks are prime examples of systems where a very high degree of reliability is expected. Reliability is the probability of a device or system performing its function adequately for the period of time intended and intented operating conditions intented. This paper shows that a better meshed distribution configuration over the case study of radial configuration distribution system was selected by comparing the indices obtained from EDSA\`s reliability worth assessment of distribution systems program.

• Proceedings of the KIEE Conference
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• summer
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• pp.545-547
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• 2004

This paper proposes the novel investment priority decision method for distribution facilities considering the potential failure rate and the influence of customer caused by faults in distribution networks. The Proposed method decides the investment priority of the facilities combining, by the fuzzy rules, the KEPCO's priority decision for investment and the priority decision considering SAIFI(System Average Interruption Frequency Index) and SAIDI(System Average Interruption Duration Index). To verify the performance of the proposed method, these works utilized the projects for weak facility reinforcement planned in KEPCO in the Busan region in 2003 and 2004. The evaluation results showed that the reliability of the KEPCO in the Busan region using the proposed method can be enhanced more than using the conventional KEPCO's method.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.11
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• pp.548-556
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• 2005

Reliability evaluation of power distribution system is very important to both power utilities and customers. It present the probabilistic number and duration of interruption such as failure rate, SATDI, SAIFI, and CAIDI. However, it has a fatal weakness at reliability index because of accuracy of failure rate. In this paper, the Time-varying Failure Rate(TFR) of power distribution system equipment is extracted from the recorded failure data of KEPCO(Korea Electric Power Corporation) in Korea. For TFR extraction, it is used that the fault data accumulated by KEPCO during 10 years. The TFR is approximated to bathtub curve using the exponential(random failure) and Weibull(aging failure) distribution function. In addition, Kaplan-Meier estimation is applied to TFR extraction because of incomplete failure data of KEPCO. Finally, Probability plot and regression analysis is applied. It is presented that the extracted TFR is more effective and useful than Mean Failure Rate(MfR) through the comparison between TFR and MFR