• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.132-140
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected two wind farms. Control of Jeju power system will be difficult if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms and HVDC overhaul have an effect on Jeju system or not during the HVDC overhaul. We found that the frequency of Jeju system is very unstable and the voltage distortion excess the limitation. Harmonic currents of wind farms flew into Jeju system in proportion to the power of wind turbine. And the voltage of nearby distribution line was distorted by power of wind turbine when the amount is more that 3,000[kW].

• Journal of the Korea Society for Simulation
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• v.20 no.3
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• pp.119-127
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• 2011

Overhaul and repair service means the sequential processes of disassembly, repair and reassembly for a product which has been used for a long time. Overhaul is required for the companies producing airplanes, ships, trains, military weapons and heavy industrial equipments which are very expensive and have a long life cycle. The most important performance measure of the overhaul repair shop is usually the lead time. Thus, how to design the manufacturing system to meet the delivery date is a major concern in overhaul repair shop. This paper introduces the case study of an overhaul repair shop producing military weapon systems with the 3D simulation tool, $QUEST^{TM}$. At first, the characteristics of overhaul shop and what should be considered for simulation modeling are explained. Then, various simulation scenarios including two types of disassembly systems, one is flow line system and the other is cell system, are discussed with the results of simulation experiments.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.170-173
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• 2008

제주의 전력계통은 HVDC로 육지계통과 연계되어 있으며 3곳의 풍력발전단지가 연계되어 있다. 향후 대규모의 풍력발전이 연계된 상황에서 HVDC Overhaul을 시행하거나 어떤 사고로 HVDC가 끊어진다면 제주계통을 정상적으로 유지하는 것이 어려울 수도 있다. 이에 본 본문은 Overhaul 기간에 한경풍력 2단계가 제주계통의 전력품질에 어떤 영향을 미치는지 분석하였다. Overhaul 기간에는 제주계통의 주파수가 매우 불안정하여 풍력발전량의 급격한 변동에 의하여 제주계통 전체의 주파수가 영향을 받는 것을 확인할 수 있었다.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.11
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• pp.1946-1953
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6B
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• pp.630-640
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• 2009

The thesis suggests hand-held equipment to overhaul for mobile TFT LCD/OLED module of high-performance. The established module equipment to overhaul could distinguish outputting video data to module for distinguishing flicker, but it is impossible with low system. In this thesis, supporting system could check the various supplement functions from bringing equipment to overhaul without changing design of FPGA or H/W the module various size for equipment to overhaul for module of high-performance coincidently. The system includes hand-held equipment to overhaul, test software embedded and software a base personal computer and have designed to output, save, and certify all contents of module test of hand-held equipment to overhaul to interface universal serial bus. Setting up 9 items that represent for efficient verification of the proposed system have been possible confirmation with TFT LCD/OLED module of high-performance, establishment scan time, creation gamma, changing register, supporting interface, and multi inch modules.

• Tribology and Lubricants
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• v.2 no.1
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• pp.18-29
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• 1986

한국철도에서는 현재 약 450냥에 가까운 Diesel 기관차를 보유하고 있으며 기관의 정밀검사를 위한 Enginer의 Overhaul은 2Y검사로 2년마다 실시하고 있다. 원래 Engine의 Overhaul 주기간격은 Liner Bore와 Piston Ring 등 동력장치 조립체의 구성부품의 체험적인 마모율을 감안하여 결정되며 가장 경제적이면서도 무장애운행을 가능케 하는 것은 마모율이 최저로 유지되고 있을 때이다. 따라서 기관의 마모를 최대로 억제하는 것이 바람직하다.

• Korean Management Science Review
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• v.13 no.3
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• pp.163-172
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• 1996

According to flying hours, aircraft engines require regular overhaul for preventive maintenance. Because of hostile defense environment of Republic of Korea, the aircraft of republic of Korea Air Force(ROKAF) have been operated at the maximum level of availability and have similar overhaul schedule in several months. The concentration of overhaul schedule in a short period demands additional spare engines far exceeding the spare engines for corrective maintenance. If ROKAF decides to purchase extra engines for the preventive maintenance, the extra engines will be used only for the preventive maintenance and will be excess inventory for the most of aircraft life ccle. Also, the procurement of extra engines is significant investment for ROKAF. To help ROKAF schedule the preventive maintenance without significant spending, this study develops a dynamic programming model that is solvable using an integer programming algorithm. The model provides the number of engines that should be overhauled for a month for multiple periods under given constraints. ROKAF actually used this model to solve a T-59 engine overhaul problem and saved about three billion won at one time. ROKAF plans to use this model continuously for T-59 and other weapon systems. Thus, saving for long term will be significant to ROKAF. Finally, with minor modification, this model can be applied to deciding the minimum number of spare engines for preventive maintenance.

• Journal of the Korean Society for Railway
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• v.12 no.2
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• pp.291-301
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• 2009

This paper presents the optimal design and analysis method of the train overhaul maintenance facility based on the simulation. Because the train is composed of a coach or more, we design the simulation model after analyzing the operation of train into train, coach, coach's body parts and wheel parts and soon. In simulation analysis, we consider the critical (dependent) factors and design (independent) parameters for the selection of alternatives and optimal design. Therefore, Multi Criteria Decision Making (MCDM) is proposed for the selection of alternatives and optimal method in order to find the optimal design factors. The case study for the above approach is used for the electronic locomotive overhaul maintenance facility. This paper provides a comprehensive framework for the train overhaul maintenance facility design using the simulation, MCDM and optimal methods. Therefore, the method developed for this research can be adopted for other enhancements in different but comparable situation.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2714-2719
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• 2007

HANARO, an open-tank-in-pool type research reactor of 30 MWth power in Korea, has been operating normally since its initial criticality in February, 1995. For the last about ten years, A cooling tower of a secondary cooling system has been operated normally in HANARO. Last year, the cooling tower has been overhauled for preservative maintenance including fills, eliminators, wood support, water distribution system, motors, driving shafts, gear reducers, basements, blades and etc. This paper describes the results of the overhaul. As results, it is confirmed that the cooling tower maintains a good operability through a filed test. And a cooling capability will be tested when a wet bulb temperature is maintained about 28 $^{\circ}C$ in summer and the reactor is operated with the full power.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.2
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• pp.76-82
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• 2019

This study has done to search for a solution to remove risk limitedly caused by separating weapon system acquisition from operation and maintenance at the view point of Logistic Commander who's responsible for stable operation and maintenance after acquiring weapon system. At the System development stage, unverified overhaul development plan may cause additional manpower and costs after the development, and furthermore it is likely to have risk to lower reliability of the military. Thus, research and development agency should write overhaul development plan at the System development stage, and it should be verified through evaluation and verification test. Secondly, during research and development, institutional supplementation is needed to calculate human and material resources writing overhaul development plan. Thirdly, it should be able to analyze proper operation & maintenance plan and cost for overhaul plan at the pre-investigation stage. Fourthly, the base which can develop overhaul concept and overhaul factors should be included in the need and need determination document. Lastly, for the weapon system which has small amount of high power figure, project management should be performed to be able to specify at the each acquisition level of weapon system to realize Article 28, clause 3 and 4 of Defense business law.