• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.430-431
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• 2011

Recently the power system consists of the more complicated structure, due to increase of power demands. In this circumstance, the congestion and loss capacity in transmission line is also increased. Accordingly, the investment planning of transmission system is required to reduce the congestion and loss of the transmission line. In study of the planning of domestic and international transmission expansion, the reliability of transmission planning and minimizing Investment cost is focused. However, the study has not been performed systematically in economic aspects. Typically, the congestion and loss costs have been individually calculated. It is not consider the mutual relationship between the congestion cost and the loss cost. This paper proposes a method to compute concurrently the congestion and loss costs. This purpose is to calculate the more exact value for economic assessment of the power system operation.

• Journal of Power Electronics
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• v.13 no.5
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• pp.737-745
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• 2013

Offshore wind farms are rapidly growing owing to their comparatively more stable wind conditions than onshore and land-based wind farms. The power capacity of offshore wind turbines has been increased to 5MW in order to capture a larger amount of wind energy, which results in an increase of each component's size. Furthermore, the weight of the marine turbine components installed in the nacelle directly influences the total mechanical design, as well as the operation and maintenance (O&M) costs. A reduction in the weight of the nacelle allows for cost-effective tower and foundation structures. On the other hand, longer transmission distances from an offshore wind turbine to the load leads to higher energy losses. In this regard, DC transmission is more useful than AC transmission in terms of efficiency because no reactive power is generated/consumed by DC transmission cables. This paper describes some of the challenges and difficulties faced in designing high-power-density power conversion systems (HPDPCSs) for offshore wind turbines. A new approach for high gain/high voltage systems is introduced using transformerless power conversion technologies. Finally, the proposed converter is evaluated in terms of step-up conversion ratio, device number, modulation, and costs.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.4
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• pp.708-717
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• 2009

Recently, Korea government decided to introduce RPS (Renewable Portfolio Standard) mechanism which requires electricity providers to gradually increase the amount of renewable energy sources such as wind, solar, bioenergy, and geothermal. As a consequence, it is expected that the long-term fuel mix would be changed to result in more expensive production and the increased production costs would be distributed to the rate payers via electricity tariffs. This paper presents the change in long-term fuel mix in year 2020 with the four RPS scenarios of 3%, 5%, 10% and 20%, and the methodologies for collecting the increased production costs through new tariff schedule. The studies on long-term fuel mix have been carried out with the GATE-PRO (Generation And Transmission Expansion Program) optimization package, a mixed-integer program developed by the Korea Energy Economics Institute and Hongik university. Three methodologies for distributing the production costs to the rate payers have also been demonstrated.

• Proceedings of the KIEE Conference
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• 2001.11b
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• pp.67-69
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• 2001

It is required to develop a rational transmission tariff system to ensure the fair participation of the players in the market. This study suggests an improved transmission tariff system which classifies the line capacity into line usage and reliability capacity based on their use and reasonably allocates the costs incurred by each of them to users. In addition, it takes the system load variations into consideration.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.763-767
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• 2002

This paper explores a structuring method for solid modeling processes of an automobile automatic transmission-lever design. The aim of this work is to establish standard procedures to minimize iterations and trial and errors during the product development process to increase development time and costs. The design of the transmission-lever is periodically required to be changed with the model change of an automobile. The transmission-lever design process has mainly depended on the designer's experience. It causes to make difficulties to handle the dependency of components. The design process can be improved by resolving the dependency problem using the DSM. The process of applying the DSM provides a systematic way for the solid modeling of transmission-lever by the consideration of geometry dependency.

• International Journal of Railway
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• v.4 no.1
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• pp.19-27
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• 2011

Many studies for improving the railway vehicle's performance and comfort such as speed, weight and noise are currently in progress. Improving the structural characteristics of the vehicle for greater noise insulation is considered important for reducing disturbance due to noise, but measuring transmission loss entails large costs. This study explores an alternative method for estimating and measuring the railway vehicle's transmission loss that involves on applying the numerical analysis coupled with scaled reverberation chamber measurement. The transmission loss measurement using scaled reverberation chamber was performed after the compensation value was found through 1mm thickness(1t) specimen. For numerical analysis, a commercially available acoustics solver VA ONE was used. The proposed method is found to lead to transmission loss measurement comparable to the measurements based on large-scale reverberation chamber. Thus, it can be argued that a reliable method has been developed for measuring railway vehicle's transmission loss.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.602-611
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• 2017

In railway systems, the exchange of information between running trains and wayside equipment is a very important role in various applications such as position detection and train control. Track circuits have been used as the medium for information transmission between trains and wayside. However, track circuits must be installed continuously along the track on the ground, resulting in an inevitable increase in installation and maintenance costs. One of the most promising solutions to reduce these costs is to mix continuous information transmission (via wireless communication) and discontinuous information transmission (via transponder). In this study, we designed antennas of railway high-speed transponder readers and tags for wireless power transmission, which can be used to transmit information from ground to high-speed trains with a maximum speed of 400km/h. We also verified system performance through computational simulation and prototyping.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.5
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• pp.871-881
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• 2010

In the uniform price electricity market or bilateral electricity market, the energy transactions in which the network is not considered and ISO's system operation costs which ISO try to minimize are settled separately. In this paper, transmission loss, one of the ISO's system operation costs, was dealt. The conventional marginal loss allocation method gives economic signals but three aspects have to be considered; excessiveness, arbitrariness and cross-subsidy. In this paper, marginal loss compensation efficiency method was suggested which consider those aspects of the conventional marginal loss allocation method. Also the characteristics of the marginal loss compensation efficiency were analyzed in the appendixes. And simple 2-bus system and IEEE 14 bus system were used to explain these characteristics.

• Tribology and Lubricants
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• v.19 no.2
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• pp.78-84
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• 2003

The SCM420 used mainly to automobile transmission gear has problems that it costs transmission gear maker much money in carburising treatment. For this, it needs to alternate the existing material and heat treatment to new gear material and surface modification. For this, friction and wear experiment according to sliding speed and applied load was carried out to evaluate the wear resistance of two transmission gear materials with carburising SCM420 and nitrocarburising NT100, The presumed wear volume was calculated with the image processing for evaluation of wear resistance of two transmission gear materials. The results show that nitrocarburising NT100 has a distinguished wear resistance than carburising SCM420.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.299-306
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• 2003

The SCM420 used mainly to automobile transmission gear has problems that it costs transmission gear maker much money in carburizing treatment. For this, it needs to alternate the existing material and heat treatment to new gear material and surface modification. For this, friction and wear experiment according to sliding speed and applied load was carried out to evaluate the wear resistance of two transmission gear materials with oxidation nitrocarburising and non-oxidation nitrocarburising NT100, The presumed wear volume was calculated with the image processing for evaluation of wear resistance of two transmission gear materials. The results show that the oxidation nitrocarburising has a distinguished wear resistance than non-oxidation nitrocarburising.