• The Transactions of The Korean Institute of Electrical Engineers
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• v.65 no.6
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• pp.1103-1107
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• 2016

The automatic tensioning device of the catenary system constantly maintains the tension of the trolley wire by absorbing the variations due to the elasticity of the line caused by temperature variation. The tension plays an important role in affecting the electric motorcar operation directly. This paper suggests the methodology of the life cycle extension and the maintenance of the automatic tensioning device by means of performance diagnosis of the pulley type automatic tensioning device which has been commonly used for the electric railway system. Through conducting performance diagnosis and comparative test for the wornout pulley type automatic tensioning device by replacing the components such as the bearing and the bearing shaft without replacing all the assembly, the tensioning device is analyzed whether it is properly functioned. Provided that the maintenance regulation is reinforced so as to implement the bearing replacement through periodical precise inspection along with random check-up inspection which is now carried out by the operating organizations, it is ensured that the life cycle extension and the reduction of maintenance cost of the tensioning device could be achieved.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.27 no.11
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• pp.1933-1940
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• 2003

Recently, the importance of plant maintenance(PM) was highly raised to provide efficient plant operation which highly affects the productivity. For this reason, a number of engineering methodologies, such as risk-based inspection(RBI), fitness for service guidelines(FFS), plant lifecycle management(PLM), have been applied to improve the plant operation efficiency. Also, a network-based business operation system, which is called ERP(Enterprise Resource Planning), has been introduced in the field of plant maintenance. However, there was no attempt to connect engineering methodologies to the ERP PM system. In this paper, a knowledge-based information system for the plant operation of steel making company has been proposed. This system which is named as K-VRS(Knowledge-based Virtual Reality System), provides a connection between ERP plant maintenance module and knowledge-based engineering methodologies, and thus, enables network-based highly effective plant maintenance process. The developed system is expected to play a great role for more efficient and safer plant maintenance.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.10 no.1
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• pp.37-43
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• 2014

Nuclear power plants(NPPs) are consisted of power production functions and safety functions preventing leakage of radiation. Operators working in NPPs shall maintain these functions during an operation period through various activities such as improvement & modification, corrective maintenance, preventive maintenance and surveillance test. According to the performance of these work activities, there are configuration changes in NPPs systems. Its changes cause the increase of safety risks(CDF) and plant trip risks. Recently, the importance of risk management is increasing gradually in the operation process of NPPs. Therefore, this paper presents the work management methods using the various risk monitoring systems during power operation and overhaul period. Also this paper suggests the optimum application ways of risk systems for work management.

• Journal of Electrical Engineering and Technology
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• v.13 no.4
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• pp.1631-1637
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• 2018

Electric utilities has been considered the necessity to introduce asset management of electric power facilities in order to reduce maintenance cost of existing facilities and to maximize profit. This paper aims to provide data that can helpful to make profitable decision in terms of power transformers which have a significant part in the power system. Therefore, this study is modeling input cost for power transformer during its entire life and also the life cycle cost (LCC) technique is applied. In particular, the variation of transformer state related with maintenance and the variation of the EUAC curve based on cost and effect of maintenance is examined. In this study, the trend of the equivalent uniform annual cost (EUAC) according to maintenance cycle and cost of equipment is analyzed. In line with that, sensitivity analysis influenced by the changes of other cost factors was performed.

• Proceedings of the KSR Conference
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• 2007.11a
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• pp.1115-1120
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• 2007

Recently, the development of the paved track is required as a low-maintenance of conventional line. The main reason is that the line capacity and bearing of track are increased progressively. The important factors of paved track are stability and applicability. To be based on this subject, Cement Mortar Pouring(CMP) paved track is developed. CMP paved track is a kind of ballast reinforced track using the prepacked concrete technique. The most important thing to design the paved track is to optimize the track structure considering various conditions. In this study, the CMP track is constructed(30m) on a test line and the track performance tested by running train to evaluation the capability and workability. The track performance are tested to confirm the vibration acceleration of the car body, wheel and track, accumulated settlement, track irregularity and crack of surface.

• Proceedings of the KSR Conference
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• 2002.05a
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• pp.220-227
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• 2002

Now, Korea National Railroad is planning many ways to increase the maximum operating speed of train up to 200km/h by 2010. Among those ways, connecting conventional line with the KTX is the strongest alternative. Mostly, conventional lines are consisting of both KS50N and KS6O rail. However, the excessive abrasion might be occurred between wheel and rail when the KTX designed to operate on UIC60 is operating on the conventional line. On this study, new standard of 60kg-class rail considered suitability for both KTX and wheel used in conventional line is presented. It seems to be an effective solution for increasing maintenance costs expected when commercial speed of conventional line is increasing.

• Proceedings of the KIEE Conference
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• 2002.07a
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• pp.169-171
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• 2002

The western route of KEPCO's 765kV transmission line has been tentatively operating as 345kV voltage before commercial operation. After finishing the test operation of 765kV substation in 2002. KEPCO decided to operate the 765kV line for commercial operation. During the applying of 765kV voltage to the transmission line, double circuit transmission line will be operated with two voltage grades of 765kV and 345kV. Because the earthing switch is installed on both end of transmission line, we had estimated the electrostatic induction voltage and electromagnetic induction current before the line energizing in order to confirm the ratings of earthing switch. The induced voltage and current is very important for the maintenance of parallel circuit. This paper describes the simulation study of electrical phenomena such as electrostatic induction voltage from the parallel line and electromagnetic induction current from the parallel circuit. The transmission line model was developed by EMTP (Electro-Magnetic Transient Program).

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.5
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• pp.1-9
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• 2015

Recently Honam high-speed railroad line is constructed in southern part of Korea. This line is for next generation HST named HEMU-430X. But there is a limestone mine near this line and this mine will make a process to dig a passageway under the railway line. In this case, safety of railroad system and stability of mine are crucial problems on both sides. By measuring mine blasting vibration and calculating regression equation, effect of mine blasting to train running is investigated quantitatively. 0.5 kine (cm/sec) is applied as a management specification of vibration based on field measurement. In this study, changes of blasting patterns are suggested to control vibration of mine blasting. And the effect of train vibration to mine is also invesitigated by numerical analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.6 no.2
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• pp.127-133
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• 2002

Most structures are constantly influenced by repeated weathering phenomena and load action during a period of its utilization, and their component materials become superannuated and their design performance becomes slowly lost. Therefore, it is thought that it is necessary to develop the online monitoring system that can make a great contribution to the maintenance management and disaster prevention of the building structure by sensing any slight change of the entire structure regardless of its inside and outside. Especially, this study was intended to explain the entire system of the online structure by interpreting welded built-up H-beams, of structural steel members having many advantages in terms of the qualities of structural materials, through limit state design, and presenting the basic plan to apply it to the structure.

• Proceedings of the KSR Conference
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• 2003.10c
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• pp.252-257
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• 2003

It is necessary to have a maintenance of track and its equipment for safety and s the railroad transportation. In the paper, we examine the safety problems, protecti and composition of protection system for safety within the track which RTRI develo system consists of a mobile business tool carried by each worker. a terminal of t platform temporarily installed in the maintenance car. a connector attached to signalling system and a central administrative device installed at the control cen used independently to detect positions of workers and maintenance cars. Each m correctly grasp the geometrical relations with other workers cars and other objects conditions based on the state information exchanged between the machines by the control protocol. the track occupancy monitor information broadcast by th administrative device and the line information. The protection system executes its f this basic structure.