• Journal of Electrical Engineering and Technology
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• v.9 no.4
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• pp.1248-1257
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• 2014

Overhead transmission lines are crucial components in power transmission systems. Well-designed maintenance strategy for overhead lines is required for power utilities to minimize operating costs, while improving the reliability of the power system. This paper presents a maintenance priority index (MPI) of overhead lines for a reliability centered approach. Proposed maintenance strategy is composed of a state index and importance indices, taking into account a transmission condition and importance in system reliability, respectively. The state index is used to determine the condition of overhead lines. On the other hand, the proposed importance indices indicate their criticality analysis in transmission system, by using a load effect index (LEI) and failure effect index (FEI). The proposed maintenance method using the MPI has been tested on an IEEE 9-bus system, and a numerical result demonstrates that our strategy is more cost effective than traditional maintenance strategies.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.54 no.5
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• pp.226-233
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• 2005

As the power demand has been increasing, a fault current problem is becoming more serious in real power system. Various ways like bus-split operation, transmission line open operation, are used in Korean power system for solving the problem. In this time, superconducting FCL(Fault Current Limiter) has been developed as a vary attractive alternative since HTS(High Temperature Superconductivity) was discovered. Korea, a project developing superconducting FCL to apply to 154kV transmission system is proceeding. Therefore, a power system analysis for SFCL application to power system is necessary, This paper presents the determination of quenching resistance and the selection of optimal cites when 154kV HTS-FCL is applied to Korean power system.

• Journal of Biosystems Engineering
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• v.16 no.3
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• pp.239-247
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• 1991

This study was conducted to investigate the feasbility of continuously variable V-belt transmission(CVVT) as automatic power transmission system of combine harvesters. An experimental set-up for testing the performance of CVVT and the automatic transmission system was designed and used to analyze the power transmission characteristics of CVVT. The transmission efficiency of CVVT was increased logarithmically with increase of the load of driven shaft, but was not affected by the speed ratios of transmission. More than 80% of transmission efficiency was obtained in the 25N-m load and more of driven-shaft, and the maximum efficiency was 88~91%. When rapid speed change of the CVVT was attempted, the speed of driven shaft was stabilized within about 0.4 seconds after shift operation in both cases of increasing and decreasing of the speed.

• Transactions of The Korea Fluid Power Systems Society
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• v.1 no.2
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• pp.20-25
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• 2004

In this study, a position control characteristics of pneumatic cylinder with transmission line is analyzed. Dynamic characteristics of transmission line using compressible fluid is changed by the flowing stiles of the fluid the diameter and the length of the line. But, the effect of the change of dynamic characteristics of transmission line by the flowing states on the position control characteristics can be neglected because of the friction force of the pneumatic cylinder. So, We assume that the position control characteristics is affected by the diameter and length of the transmission line. The experimental results according to the change of parameter of the transmission line show that the relation between the parameter of the transmission line and the position control characteristics of pneumatic cylinder driving system with the transmission line.

• Proceedings of the KIPE Conference
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• 1998.10a
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• pp.903-908
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• 1998

This paper aims at investigating the characteristics of the operating modes of two-module Thyristor Controlled Series Compensator (TCSC) in a power transmission system. The operating modes of two-module TCSC are defined, analyzed and compared to those of single-module TCSC are defined, analyzed and compared to those of single-module TCSC. The load flow program, the stability calculation program and Electro Magnetic Transient Program (EMTP) simulation of a TCSC power transmission system are developed for the performance evaluation of two-module TCSC as a power flow controller. In the process of the simulation study, the potential problem areas of the TCSC power transmission system are identified.

• Transactions of The Korea Fluid Power Systems Society
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• v.6 no.3
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• pp.23-31
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• 2009

Counter shaft transmission is a popular automatic transmission power train in construction vehicles such as wheel loader and forklift. The gear train layout of counter shaft transmission is a very basic and important development stage because it affects the most of components design including hydraulic system and shift control algorithm, etc. This paper presents a design methodology for the gear train layout from the analysis of power flow path and clutch hook-up of the existing counter shaft transmission that is adopted in commercialized construction vehicles. Also, independent constraints for the meshed gear ratios are derived in order to realize forward 4-speed and reverse 3-speed gear ratio. The layout design principle proposed here was applied to the new original counter shaft transmission that is underdevelopment.

• ETRI Journal
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• v.30 no.6
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• pp.844-849
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• 2008

A new transcutaneous energy transmission (TET) system was developed for transmitting electrical power to an implanted device, such as an artificial heart in a patient's body. This new design can maintain a stable output voltage independent of the load resistance. The system includes a compensation capacitor to reduce energy loss and increase power transfer efficiency. Experimental results show that the output voltage of the receiving coil changes very little as the load resistance varies from 14.8 ${\Omega}$ to 15 $k{\Omega}$, which corresponds to a change in output power from 0.1 to 97 W.

• Proceedings of the KIEE Conference
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• 2002.07d
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• pp.2212-2215
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• 2002

This dissertation suggests and implements a middle level network which is called PICNET-NP (Plant Implementation and Control Network for Nuclear Power Plant). PICNET-NP is based partly on IEEE 802.4 token-passing bus access method and partly on IEEE 802.3 physical layer. For this purpose a new interface a physical layer service translator, is introduced. A control network using this method is implemented and applied to a distributed real-time system. To verify the performance of proposed protocol experimental were carried out, and the following results are obtained. 1) proper initialization of the protocol. 2) normal receiving and transmission of data. 3) proper switching of transmission media in case of a fault condition on the one of transmission media. The proposed protocol exhibits the excellent performance in the experimental system. From the test results in the experimental system, the proposed protocol, PICNET-NP, can be used for the upgrading of a nuclear power plant and the distributed control system in the next generation of nuclear power plant.

• Proceedings of the KIEE Conference
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• summer
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• pp.51-53
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• 2004

KEPCO is now promoting the overseas transmission businesses on the basis of competitive transmission technology. This paper deals with a development study on the power system network analysis in Myanmar which was performed as the first overseas transmission business of KEPCO. The aim of this study is to establish comprehensive and stable power system network plan by analyzing the current and future system in Myanmar.

• Proceedings of the KIEE Conference
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• summer
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• pp.488-490
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• 2004

The technical data for transmission line design and maintenance are calculated by a very complicated numerical formula so it is almost impossible to solve them by hand. Therefore the TOWER+ EXPERT SYSTEM was developed to systematically support technical data for transmission line design and maintenance. This system is able to calculate technical data which is applied to all conductors in our county, - that is 12 kinds of systems with 86 numbers of standard conductors, - and is programed to be user friendly by adopting dialogue windows, menu selection functions. Moreover, it minimizes input data by automatically providing standard transmission line design data, and it includes guidance of applicable work, program usage, data input process, help, explanation of terms and automatic error recovery functions that even a beginner can easily use.