• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.419-421
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• 2001

The large distribution automation system for metropolitan city was developed in KEPCO just recently. This system has many functions for remote control and data acquisition, and it will be linked the other computer aided system such as NDIS(new distribution automation system) and SCADA(supervisory control and data acquisition) to construct the database of DAS(distribution automation system).

• Proceedings of the KIEE Conference
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• 2001.07a
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• pp.19-21
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• 2001

Nowadays, small scale DGS(Distributed Generation System), as a wind power generation or photovoltaic generation, becomes to be introduced into the power distribution system. But in that case it is difficult to properly maintain the terminal voltage of low voltage customers by using only LDC(Line Drop Compensator). So, it is necessary to determine the permissible operation limit of the introduced DGS for proper voltage in distribution system. In this paper clarifies the relationship between LDC voltage regulation principle and real, reactive power of DGS, and examines the permissible operation limit of the introduced DGS in distribution system which the voltage is controlled by LDC.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.7
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• pp.333-340
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• 2002

To secure a service continuity is one of the most important mission in the ower distribution system operation. In this paper the necessary and sufficient condition to guarantee 100% service restoration capability for any fault on the system is reported. An evaluation methodology of the restoration capability(or restorability) is developed based on the developed restoration conditions. Applications of the developed concept to the system operation in the normal and emergency states, that would enhance the supply reliability of the system are described. They include enhancement of restoration capability adapting to load change, identification of best open switch and supervised switch positions.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.49 no.11
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• pp.566-574
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• 2000

This paper propose a heuristic algorithm based on the Branch-Exchange (BE) method to solve Optimal feeder Routing(OFR) problem for the distribution system planning. The cost function of the OFR problem is consisted of the investment cost representing the feeder installation and the system operation cost representing the system power loss. We propose a properly designed heuristic strategy, which can handle the horizon-year expansion planning problem of power distribution network. We also used the loop selection method which can define the maximum loss reduction in the network to reduce calculation time, and proposed a new index of power loss which is designed to estimate the power loss reduction in the BE. The proposed index, can be considered with both sides, the low voltage side and voltage side branch connected with tie one. The performances of the proposed algorithms and loss index were shown with 32, 69 example bus system.

• Journal of the Semiconductor & Display Technology
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• v.18 no.3
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• pp.60-65
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• 2019

In this paper, the hybrid illumination system for effectively detecting surface defects in steel plate with lowcontrast, non-uniformity and featureless is designed based on illuminance uniformity. First of all, characteristics of steel plate defects were considered and typical inspection illumination system is implemented. Optimum illumination parameters for uniformly illuminating an inspection area in the typical illumination system are selected based on the illuminance uniformity and illuminance distribution measurement. The illuminance uniformity and illuminance distribution are measured using an illuminometer based on the arduino. Through illuminance distribution analysis of the typical illumination, an hybrid illumination is designed by fusing bi-directional illumination and coaxial illumination. The hybrid illumination showed higher uniformity ratio and illuminance distribution than the typical illuminations. The hybrid illumination system showed the ability to uniformly illuminate the entire inspection region of steel plate surface.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.58 no.9
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• pp.1651-1657
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• 2009

In this paper, restoration solution algorithm to improve reliability better than restoration system of DAS(Distribution Automation System) is proposed in IDMS(Intelligent Distribution Management System). A strategy of IDMS restoration system to improve reliability and efficiency is proposed by analysis restoration system in DAS. Restoration sequence algorithm, distributed restoration solution algorithm considering a characteristic and a suitable restoration solution algorithm in IDMS are proposed. In the case study, algorithms have testified with example distribution network by C language

• Structural Engineering and Mechanics
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• v.70 no.1
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• pp.81-96
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• 2019

In this paper, a hybrid uncertain model is applied to system reliability based design optimization (RBDO) of trusses. All random variables are described by random distributions but some key distribution parameters of them which lack information are defined by variation intervals. For system RBDO of trusses, the first order reliability method, as well as monotonicity analysis and the branch and bound method, are utilized to determine the system failure probability; and Improved (${\mu}+{\lambda}$) constrained differential evolution (ICDE) is employed for the optimization process. System reliability assessment of several numerical examples and system RBDO of different truss structures are proposed to verify our results. Moreover, the effect of different classes of interval distribution parameters on the optimum weight of the structure and the reliability index are also investigated. The results indicate that the weight of the structure is increased by increasing the uncertainty level. Moreover, it is shown that for a certain random variable, the optimum weight is more increased by the translation interval parameters than the rotation ones.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.17 no.2
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• pp.19-27
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• 2007

Broadcasting contents protection system for HDTV has many difficult to apply file encryption technology that using the existing DRM systems. Therefore, this system has to be processed as accommodative about broadcasting contents format such as TS and PS and so on. Also, this system must support efficient encryption technology and random access mode. In addition, this system must have suitable key distribution mechanism in broadcasting environment. In this paper, we propose and implement encryption/key distribution scheme applicable to encoder/decoder without changing the existing MPEG system.

• Progress in Superconductivity and Cryogenics
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• v.11 no.3
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• pp.50-54
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• 2009

In Korea, 22.9kV 50MVA HTS (High Temperature Superconducting) cables and 630A/3kA hybrid SFCLs (Superconducting Fault Current Limiters) have been or are being developed by LS Cable, LS Industrial System, and Korea Electric Power Research Institute. They will be installed at Icheon 154kV Substation for real-power-distribution-system operation in 2010. This paper proposes specification of current limiting resistor/reactor for the SFCL and fault current condition of the HTS cable for applying the superconducting devices to Korean power distribution system, from the viewpoint of power system protection.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.6
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• pp.290-295
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• 2002

The present assignment in installing the number of switches for distribution line was made on the basis of a normal feeder capacity 7,000kVA in KEPCO(Korea Electric Power Corporation), Korea. But the normal capacity is revised to 10000kVA in 1998. Even increasing limit of the operating capacity of the distribution lines enables us to give some benefit for the operation flexibility and investment cost of the distribution system. It is disadvantageous in the viewpoint of supply reliability. In distribution systems, switches are equipped to improve the reliability of distribution systems by minimizing the outage section due to fault and maintenance. Utility generally improves the reliability by minimizing the length of outage section, which is caused by fault and maintenance, through switch equipment on distribution system. In order to cope with the changes such as operation capacity, it is necessary to study whether the present criteria is reasonable or not, also to confirm whether the present criteria of installing switches in line is improved or not. In this study, we proposes the number of switch per feeder on the basis of present operation capacity in distribution system.