• KIEE International Transactions on Power Engineering
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• v.3A no.3
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• pp.119-123
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• 2003

Successful operation of power systems under the deregulated electricity market depends on the management of the transmission system reliability. Quantitative evaluation of the transmission system reliability is an important issue. Particularly, the nodal reliability indices can be of value in the management and control of congestion and reliability of the transmission system under the deregulated electricity market. In this study, a method developed for the reliability evaluation of the transmission system is presented. The Monte Carlo methods are used because of their flexibility when complex operating conditions are being considered. The usefulness and effectiveness of the proposed method are illustrated by a case study with the KEPCO system.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.1
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• pp.9-16
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• 2003

In this paper, we propose a reliability evaluation method considering the momentary interruptions of power distribution systems. The results of research are concentrated on two parts. One is the analytic and probabilistic reliability evaluation of power distribution system considering the momentary interruptions and the other is the reliability cost evaluation that unifies the cost of sustained and momentary interruptions. This proposed reliability cost evaluation methodology is also divided into the analytic and probabilistic approach and the time sequential Monte Carlo method is used for the probabilistic method. The proposed methods are tested using the modified RBTS (Roy Billinton Test System) form and historical reliability data of KEPCO (Korea Electric Power Corporation) system. Through the case studies, it is verified that the proposed reliability evaluation and its cost/worth assessment methodologies can be applied to the actual reliability studies.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.12
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• pp.2119-2124
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• 2010

Reliability evaluation of power distribution system is the evaluation for all customers supplied from one power source as main transformer located in substation. However, power sources include not only the main transformer but distributed generations. Typical reliability evaluation has focused on configuration of power system with one source including failure rates of equipment. In this paper, we focus on not only configuration but power sources as distributed generations. New reliability evaluation method using power supplied probability (PSP) is proposed. The proposed evaluation method are proved through case studies.

• Journal of Electrical Engineering and Technology
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• v.10 no.4
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• pp.1422-1431
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• 2015

The reliability of power system components can be affected by a numbers of factors such as the health level of components, external environment and operation environment of power systems. These factors also affect the electrical parameters of power system components for example the thermal capacity of a transmission element. The relationship of component reliability and power system is, therefore, a complex nonlinear function related to the above-mentioned factors. Traditional approaches for reliability assessment of power systems do not take the influence of these factors into account. The assessment results could not, therefore, reflect the short-term trend of the system reliability performance considering the influence of the key factors and provide the system dispatchers with enough information to make decent operational decisions. This paper discusses some of these important operational issues from the perspective of power system reliability. The discussions include operational reliability of power systems, reliability influence models for main performance parameters of components, time-varying reliability models of components, and a reliability assessment algorithm for power system operations considering the time-varying characteristic of various parameters. The significance of these discussions and applications of the proposed techniques are illustrated by case study results using the IEEE-RTS.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.397-399
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• 2000

This paper presents a method for assessing reliability indices of transmission system. Because successful operation of electric power under the deregulated electricity market depends on transmission system reliability management, quantity evaluation of transmission system reliability is very important. The key point idea is based on that the reliability level of transmission system is equal to reliability level difference of between composite power system(HLII) and generation system(HLI). It is sure that risk indices of reliability of composite power system are larger than those of generation system. It is the reason that composite power system includes uncertainties and capacity limit of transmission lines. The characteristics and effectiveness of this methodology are illustrated by the case study using MRBTS.

• Proceedings of the KSR Conference
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• 2005.05a
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• pp.806-812
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• 2005

This paper proposes a new reliability evaluation for traction power system. The electric railway consists of traction power systems, various vehicles, operating equipment, track, overhead line and electric equipment. It is a fundamental function of traction power systems that supply customers with reasonable price, acceptable reliability and high quality power. In a general way, the power system reliability deals with the ability to satisfy load demands in supply capability or rating of every factor. On the other hand, the reliability of traction power systems has been focused on train time delay caused by power outage. In this paper, we make a selection optimum reliability indices for the reliability evaluation of electric traction power systems. The reliability study not only applies a plan for traction supply system after detecting the vulnerable point of existing traction supply systems but also makes a role in stable operating railway.

• Proceedings of the KIEE Conference
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• 2003.11a
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• pp.62-66
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• 2003

In recent, the importance and necessity of some studies on reliability evaluation of grid comes from the recent black-out accidents occurred in the world. The quantity evaluation of transmission system reliability is very important under competitive electricity environment. The reason is that the successful operation of electric power under the deregulated electricity market depends on transmission system reliability management. This paper introduces features and operation modes of the Transmission Reliability Evaluation for Large-Scale Systems(TRELSS) Version 5_1, a program made in EPRI, for assessing reliability indices of composite power system. The package accesses not only bulk but also buses indices for reliability evaluation of composite powers system. The characteristics of the TRELSS program are illustrated by the case studies using the IEEE 25buses system.

• KIEE International Transactions on Power Engineering
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• v.5A no.3
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• pp.286-292
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• 2005

As the power industry moves towards open competition, there has been a call for methodology to evaluate power system reliability by using composite interruption cost. This paper presents algorithms to evaluate the interruption cost of distribution power systems by taking into consideration the failure source and the composite customer interruption cost. From the consumer's standpoint, the composite customer interruption cost is considered as the most valuable index to estimate the reliability of a power distribution system. This paper presents new algorithms that consider the load by customer type and failure probability by distribution facilities while calculating the amount of unserved energy by customer type. Finally, evaluation results of unserved energy and system interruption cost based on composite customer interruption cost are shown in detail.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.1
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• pp.1-7
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• 2015

This paper proposes probabilistic reliability evaluation model of power system considering Wind Turbine Generator(WTG) integrated with Energy Storage System(ESS). Monte carlo sample state duration simulation method is used for the evaluation. Because the power output from WTG units usually fluctuates randomly, the power cannot be counted on to continuously satisfy the system load. Although the power output at any time is not controllable, the power output can be utilized by ESS. The ESS may make to smooth the fluctuation of the WTG power output. The detail process of power system reliability evaluation considering ESS cooperated WTG is presented using case study of Jeju island power system in the paper.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.12
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• pp.705-712
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• 2003

In this paper, we propose new unified methodologies of reliability and its cost evaluation in power distribution systems. The unified method means that the proposed reliability approaches consider both conventional evaluation factor, i.e. sustained interruptions and additional ones, i.e. momentary interruptions and voltage sags. Because the three voltage quality phenomena generally originate from the outages on distribution systems, the basic and additional reliability indices are summarized considering the fault clearing mechanism. The proposed unified method is divided into the reliability evaluation for calculating the reliability indices and reliability cost evaluation for assessing the damage of customer. The analytic and probabilistic methodologies are presented for each unified reliability and its cost evaluation. The time sequential Monte Carlo technique is used for the probabilistic method. The proposed DVL(Demand Varying Load) model is added to the reliability cost evaluation substituting the average load model. The proposed methods are tested using the modified RBTS(Roy Billinton Test System) form and historical reliability data of KEPCO(Korea Electric Power Corporation) system. The daily load profile of the each customer type in domestic are gathered for the DVL model. Through the case studies, it is verified that the proposed methods can be effectively applied to the distribution systems for more detail reliability assessment than conventional approaches.