• Journal of Electrical Engineering and Technology
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• 제9권5호
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• pp.1482-1488
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• 2014

The reliability evaluation of the electrical distribution networks (EDN) requires sufficient consideration of the effects of planned outages. The planned outages of the EDN can be divided, by outage models and their effects on the reliability into two major categories: by equipment and by feeder. After studying the characteristics of different categories of planned outages, this paper expands the classification of load points by outage time from 4 types to 7 types and defines corresponding reliability parameters for the different types. By using the section algorithm, this paper proposes a reliability evaluation technique of EDN considering equipment random failures and two categories of planned outages. The proposed technique has been applied to the RBTS-BUS6 test system and some practical EDNs in China. The study results demonstrate that the proposed technique is of higher practical value and can be used for evaluating the reliability performance of EDN more efficiently considering the planned outages.

• 대한전기학회논문지:전력기술부문A
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• 제55권4호
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• pp.172-178
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• 2006

In this paper, an advanced demand clustering algorithm which can explore the planned maintenance outage of generators in changed electricity industry is proposed. The major contribution of this paper can be captured in the development of the long-term estimates for the generation availability considering planned maintenance outage. Two conflicting viewpoints, one of which is reliability-focused and the other is economy-focused, are incorporated in the development of estimates of maintenance outage based on the advanced demand clustering algorithm. Based on the advanced clustering algorithm, in each demand cluster, conventional effective outage of generators which conceptually capture maintenance and forced outage of generators, are newly defined in order to properly address the characteristic of the planned maintenance outage in changed electricity markets. First, initial market demand is classified into multiple demand clusters, which are defined by the effective outage rates of generators and by the inherent characteristic of the initial demand. Then, based on the advanced demand clustering algorithm, the planned maintenance outages and corresponding effective outages of generators are reevaluated. Finally, the conventional demand clusters are newly classified in order to reflect the improved effective outages of generation markets. We have found that the revision of the demand clusters can change the number of the initial demand clusters, which cannot be captured in the conventional demand clustering process. Therefore, it can be seen that electricity market situations, which can also be classified into several groups which show similar patterns, can be more accurately clustered. From this the fundamental characteristics of power systems can be more efficiently analyzed, for this advanced classification can be widely applicable to other technical problems in power systems such as generation scheduling, power flow analysis, price forecasts, and so on.

• 한국경영과학회지
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• 제16권2호
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• pp.164-176
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• 1991

This paper considers the model of a k-out-of-n :G system with non-identical components which are subject to both forced and planned outages. For the forced outages, it assumes that there are the independent and common-cause outage events causing component failures. Then, the objective is to derive the upper and lower bounds on the mean operating time between system failures in the ample-server model. In addtion, the mean system failure times are also considered.

• Journal of Electrical Engineering and Technology
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• 제6권4호
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• pp.431-438
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• 2011

To ensure that equipment outages do not directly impact the reliability of the ISO-controlled grid, market participants request permission and receive approval for planned outages from the independent system operator (ISO) in competitive electricity markets. In the face of major generation outages, the ISO will make a critical decision as regards the scheduling of the essential maintenance for myriads of generating units over a fixed planning horizon in accordance with security and adequacy assessments. Mainly, we are concerned with a fundamental framework for ISO's maintenance coordination in order to determine precedence of conflicting outages. Simulated annealing, a powerful, general-purpose optimization methodology suitable for real combinatorial search problems, is used. Generally, the ISO will put forward its best effort to adjust individual generator maintenance schedules according to the time preferences of each power generator (GENCO) by taking advantage of several factors such as installed capacity and relative weightings assigned to the GENCOs. Thus, computer testing on a four-GENCO model is conducted to demonstrate the effectiveness of the proposed method and the applicability of the solution scheme to large-scale maintenance scheduling coordination problems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 춘계학술대회 논문집 전력기술부문
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• pp.316-318
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• 2001

Occasionally, equipment in a distribution system fails due to damage from weather, vandalism, or other causes. In addition, it is recommended practice to have some way in which maintenance or replacement of every element in a system can be performed without causing lengthy interruption of electrical service to the customers it feeds. Thus, alternate sources, paths, and configurations of service must be planned so that both failures and maintenance do not affect customer service beyond a reasonable amount. In some cases, planning for alternate routes of service during equipment outages or emergencies -- will be the major aspect influencing selection of a feeder's capacity, type of route, or layout. We want to know the relationship between molt-dividing multi-connection and distribution reliability for contingency support considerations.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1996년도 하계학술대회 논문집 B
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• pp.701-703
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• 1996

Maintenance scheduling plays an important role in evaluating the supply reliability of power systems. Since generating units must be maintained and inspected, the generation planner must schedule planned outages during the year. Several factors entering into this scheduling analysis include: seasonal load-demand profile, amount of maintenance to bo done on all generating units, size of the units, elapsed time from last maintenance, and availability of maintenance crews. This paper proposes a new algorithm to decide the multi-year maintenance scheduling with considering the total cost. We adjust the maintenance scheduling to levelize the reliability over all period. The proposed algorithm is applied to a real size power system and the developed reliability results are obtained.

• 에너지공학
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• 제7권1호
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• pp.89-95
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• 1998

발전기의 보수계획은 전력계통의 공급신뢰도를 평가하는데 중요한 영향을 미치는 변수이다. 발전기는 반드시 검사와 보수를 해야 하기 때문에, 운전계획을 세울 때 한해의 발전기 정지계획을 고려하여 정해야 한다. 이러한 보수계획을 수립할 대에는 계절적 부하수요특징, 보수용량, 발전기 용량, 지난번 보수로부터의 경과시간 등의 여러 가지 요인들을 고려해야 한다. 본 논문에서는 발전기 보수계획 프로그램중 실용적인 방법으로 알려져 있는 LOLP(Loss of Load Probability) 평활화법을 이용하여 각 연도별 공급신뢰도를 최대로 하여 고려대상 기간 전체의 공급신뢰도를 향상시키는 보수계획 수립 알고리즘을 제안한다. 즉, 전력계통의 더 좋은 신뢰도를 얻기 위하여 전체 기간에 대한 신뢰도가 평활화되도록 보수시기를 변경하였다. 제안한 알고리즘을 실계통에 적용하여 그 유용성을 검증하였다.

• 한국전자통신학회논문지
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• 제16권6호
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• pp.1183-1194
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• 2021

전통적으로 전력시스템은 공급체계의 말단에 있는 소비자의 위치에서 보면 중앙집중화된 구조를 갖고 있다. 그러나 최근 수 십년간 지붕형 태양광, 영농형 태양광, 소형 풍력터빈, 배터리저장장치 및 스마트 가전품과 같은 분산에너지원의 등장을 보아왔다. 분산에너지원의 등장에 따라 배전계통 운전원의 역할도 확장된다. 확장된 분산전원의 진출은 배전망이나 송전망의 전통적인 계획과 운영에 영향을 주는 전력계통의 역조류와 예측성을 어렵게 할 수 있다. 이는 전형적인 계통계획, 정비 및 망관리, 정전할당 등 배전계통 운전원이 갖는 기능이 변경되어야 할 필요성을 증폭시킨다. 이 연구의 목적은 다중 분산전원을 갖는 미래 배전운전시스템을 설계하고 제안된 배전시스템 모델을 HILS로 구현 및 검증하는 것이다. 시험결과를 보면 제안된 배전시스템이 정상 영역에서 운전되고 배전선로 손실이 감소된다는 것을 보여준다.