• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.307-309
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• 2002

This paper proposes an expert system, which is able to determine the problem-solving strategy for diversity events occurred on the distribution system. The events include events related to the fault, scheduled outage and optimal operating task such as feeder line fault, line scheduled outage, line overload, system load balancing, system loss minimization, main transformer fault, main transformer scheduled outage, main transformer overload, main transformer protection control. The expert system enhances the reliability of software designed by the integrated concept for the diversity events.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.52 no.8
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• pp.463-470
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• 2003

This paper proposes an expert system, which is able to determine the problem-solving strategy for diversity events occurred on the distribution system. The events include events related to the fault, scheduled outage and optimal operating task such as feeder line fault, line scheduled outage, line overload, system load balancing, system loss minimization, main transformer fault, main transformer scheduled outage, main transformer overload, main transformer protection control. The expert system enhances the reliability of software designed by the integrated concept for the diversity events. The expert system is implemented in C language. And the effectiveness and accuracy for the expert system is verified by simulating the event cases for typical distribution model.

• Journal of the Korean Operations Research and Management Science Society
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• v.16 no.2
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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.

• The Transactions of the Korean Institute of Electrical Engineers
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• v.39 no.9
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• pp.903-911
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• 1990

When load areas on a feeder are deenergized due to faults and scheduled outage, operators need to identify neighboring feeders, try to restore customers and minimize out-of-service areas. These cases include knowledge of system states and various constraints such as voltage drop. This paper concerns the load transfer in fault restoration and scheduled outage. Also, the operating constraints such as line current capacity, relay trip current, transformer capacity, voltage drop and line loss are considered. This expert system can propose the optimal load transfer method by analyzing the system state and considering the constraints.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.9
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• pp.1171-1179
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• 2014

ISO(Independent System Operator) or TSO(Transmission System Operator) use power system analysis program to simulate contingency analysis and remedial actions to operate power system stably. Generally, power system analysis program provides automated analysis functions(or modules) to deal with wide area power system. However, because of missed contingency cases, automated contingency analysis has no practical use or has limitation. And in case of remedial action, it doesn't support automated function or takes a lot of times to study, because of simulation in manual for each cases. This paper suggests that new relation with buses and transmission line properties of power system DB used for power system analysis program to simulate automated contingency including all contingency cases needed in the field without missed cases. And it proposes automated remedial action scheme based on practical approach analysis to alleviate overloading or voltage problems. Finally it deals with automated contingency/remedial action analysis(automated scheduled outage) program which is developed by KEPCO and its performance and proposed schemes are proven by case study for real Korean power system data.

• Corrosion Science and Technology
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• v.14 no.1
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• pp.33-39
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• 2015

Pipe wall-thinning by flow-accelerated corrosion and various types of erosion is significant damage in secondary system piping of nuclear power plants(NPPs). All NPPs in Korea have management programs to ensure pipe integrity from degradation mechanisms. Ultrasonic test(UT) is widely used for pipe wall thickness measurement. Numerous UT measurements have been performed during scheduled outages. Wall-thinning rates are determined conservatively according to several evaluation methods developed by Electric Power Research Institute(EPRI). The issue of reliability caused by measurement error should be considered in the process of evaluation. The reliability analysis method was developed for single and multiple measurement data in the previous researches. This paper describes the application results of reliability analysis method to real measurement data during scheduled outage and proved its benefits.

• Proceedings of the KIEE Conference
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• 2007.11b
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• pp.229-230
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• 2007

전력계통을 구성하고 있는 모든 설비들이 항상 운전 가능한 상태에 있지는 않다. 이는 설비들이 일상적인 유지보수를 위해 정지되기도 하고, 과열 등 이상 징후를 발견하여 사전 정비를 위해서 정지되기도 하기 때문이다. 또한 인근 설비의 신중설이나 계통 구성의 변경을 목적으로 정지되기도 한다. 이 처럼 예기치 못한 고장에 의해서가 아닌 의도적인 목적으로 설비를 정지시키는 것을 휴전이라고 하고, 해당 설비의 휴전조건을 반영한 단기간의 관련 계통에 대한 운영방안을 수립하는 것이 휴전검토이다. 한편, 전력계통 계획단계에서는 설비의 휴전상태를 별도로 고려하지 않기 때문에 많은 경우 휴전이 시행되는 지역은 당초의 계통운영방안에 비하여 취약한 계통 조건이 형성되고 있다. 본 논문은 실계통 사례를 중심으로 이와 같은 설비의 휴전 특히, 발전소 인출선로 및 근단위 휴전으로 인한 과도안정도와 과부하 측면에서 계통 취약성 심화 정도를 보이고, 이어서 이들 문제점을 해소하긴 위한 방안과 그 비용을 간략히 계산하여 제시하고자 한다.

• Nuclear Engineering and Technology
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• v.35 no.6
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• pp.547-555
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• 2003

Fire hazard and risk analysis at Nuclear Power Plants is implemented on the basis of the normal operational configuration. This steady configuration, however, can be changed due to the temporary displacement of equipment, electric cable and irregular movement of workers through the fire compartments when the on-line maintenance is processed during the power operation mode or the scheduled outage mode for the refueling. With the consequence of this configuration change, the fire analysis condition and the evaluation result will be different from those that were analyzed based on the steady configuration. In this context, at this paper, the general items for the reassessment are categorized when the configuration has changed. The contemporary zone models for the detail fire analysis are also illustrated for their application for each classified condition.

• Tribology and Lubricants
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• v.10 no.4
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• pp.51-58
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• 1994

Condition monitoring technology has recently been received much attention in the light of its significance on the maintenance of complex machineries such as turbines in power plants. Currently, turbines in power plants are maintained by scheduled overhaul based on the manufacturer's recommendations and the utility's experience. Although this preventive maintenance is known to be very effective, operators have less access to identify failure of elements when it happens between overhaul period. Therefore, in this study, a development of a on-line condition monitoring system through wear debris analysis of lubricating oils is aimed with a view to detecting abnormal wear behaviour of bearings and other wet-components at an early stage, allowing better outage scheduling and minimizing forced outages. For field application purposes, the on-line system developed was installed on the turbine of the No.4 unit at Ulsan Power Plant and its performance has been evaluated on site.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.4
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• pp.31-37
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• 2011

Pressurized Water Reactor Owners Group(PWROG) proposed and applied a risk-informed inservice inspection(RI-ISI) program to alternate existing ASME Section XI periodic inspections. The RI-ISI programs enhance overall safety by focusing inspections of piping at high safety significant(HSS) and locations where failure mechanisms are likely to be present, and by improving the effectiveness on inspection of components because the examination methods are based on the postulated failure mode and the configuration of the piping structural element. The RI-ISI programs can reduce NDE, man-rem exposure, costs of engineering analysis, outage duration and chance of complicating plant operations etc. RI-ISI methods of piping inservice inspection were applied on 3 units(KSNP : Korea Standard Nuclear Power Plant) and are scheduled to apply on the other units. In this paper, we compared and showed the results of the 2 units and we concluded that the RI-ISI application could enhance and maintain plant safety and give unquantifiable benefits.