• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.228-230
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• 2002

Recently, electric power reliability of our country has been improved. However, there are still remaining problems which are short-duration variations like instantaneous and momentary interruption and voltage sag by nature calamity ; typhoon, lightning, snow, etc. Besides, power quality ; harmonics, caused by using power electronics equipments, become a hot issue Malfunction of controller and stop machinery, and losing the important data are caused by poor power quality at a couple of second. Due to those, UPS, which is made up battery, has being used, but there are several disadvantages ; long charge and discharge time, environmental problem by acid and heavy metal, and short life time. As generally know, micro-SMES is a method to settle those mentioned. However, there need huge system apparatuses in order to verify the effect of system efficiency and stability considering the size of micro-SMES, the sort of converter type, and various conditions ; inner temperature, magnetic field, quench characteristic of micro-SMES, and etc. In this paper, in order to bring the mentioned above to a settlement, a micro-SMES is modeled with characteristics of micro-SMES is interfaced to EMTOC program using Fortran program interface method. We obtained hopeful answers and made the simulation model of micro SMES.

• The Transactions of the Korean Institute of Power Electronics
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• v.13 no.1
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• pp.15-21
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• 2008

This paper presented a actual conditions on a false-tripping of ELB(Earth Leakage Breakers) and an assessment of the harmonics due to non-linear electronic equipment such as personal computers, rectifier, electric furnace and test equipments in factory electrical installation. Actual conditions on a failure of ELB were surveyed and analyzed by making up a question to safety managers of factory electrical installation. Also, power quality measurements such as harmonic currents, voltage and current waveform and current imbalance were made at various factory electrical installation where nuisance tripping of ELB is often occurred. The results of this study can be used in making decisions regarding cause of ELB trip and operating and tripping characteristics test of ELB when subjected to distorted current waveform.

• Journal of the Korean Institute of Gas
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• v.4 no.4 s.12
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• pp.13-19
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• 2000

Researches on unused energy are being continued because of the limited fossil fuel and the destruction of environment. Therefore this study was performed as follows The collectable amount of exhausted heat for an air-conditioning was calculated by the subway thermal environment prediction program. And the electric power needed by conventional heat source equipments was compared with one by unused heat source equipments when the exhausted heat was used by heat pump in heating and hot water supplying.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.15 no.4
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• pp.199-203
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• 2015

With the development of industry these days, the demand for electric power increases and the larger capacity for power transfer is required. The scales of facilities should become larger; and the relative systems are required to operate with a higher degree of reliability. Therefore, stabilization of electric power systems is an important issue. The high degree of reliability required in the process of production and supply of electric power is an essential part of industrial society. Accident such as blackouts causes a hugh amount of economic losses to the high-tech industrial society dependent upon electric power. This paper is about the basic study of the relations between the load current and lifetime of power cables in operation. In order to do the research, we installed a current transformer and an equipment for measuring temperature at the 6.6. kV cables in operation. The two equipments have been installed on the cable systems in operation for the last 20 years. Since the insulation resistance of most of the cables showed the value larger than the threshold, it was not easy to tell the remaining lifetime of cables. The load current of the cables was almost constant. The surrunding temperature was $15{\sim}25^{\circ}C$, little variation of temperature values.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.18 no.2
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• pp.157-166
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• 2004

Recently, switchboards for MV/LV distribution customers have been united and digitalized rapidly. This paper suggestes the effective information visualization method for the data mesured from cubicle switchboard for MV/LV distribution customers. We developed the algorithm that analyzes a large number of mesured data and displays them to users overall, such as fire index, power condition index, switchboard safety index, and power diminution index. Using a touch screen made users to operate it easily. User interface was also strengthened by taking graph visualization. We guess the information visualiztion method suggested in this paper shows the new direction that heavy electrical equipments including switchboards are going to develop in the future.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.10 no.1
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• pp.81-90
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• 2009

Interconnection of DG(Distributed Generation) into distribution systems and power quality are frequent subjects of discussion by distribution companies, regional electricity utilities and industrial customers. This situation makes many experts estimate a next generation of distribution systems which is composed of some micro-grids. But the proposed micor-grid is only mentioned as a small network with DG's, power quality compensators, communication and control equipments. In this paper, a decentralized coordination control algorithm of micro-grid which is able to supply the electric power with high reliability and quality, are proposed.

• Journal of Digital Contents Society
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• v.16 no.2
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• pp.197-205
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• 2015

These days due to the introduction of the subject classroom system, the classrooms for the subject are arranged and various advanced educational equipment is provided in the classroom such as the actual object image processor, electronic blackboard, and educational photographer which are helpful to the class. With the increase of these equipments, the number of remote controller of individual educational equipment also increases, therefore it is complicate to manage the remote controllers and teachers need to learn the usage of them. So the system supports a remote control for managing the educational equipment by the one remote controller and the instructional supplement. The system consists of the hardware which is similar to popular remote controller and the software which is installed on the teacher's PC and supports controlling the educational equipments, recording the instruction, writing on the blackboard, and automatic power off of the equipment. By introducing the system the teacher could reduce the time consumed by the equipment's control and useless electric waste.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.11
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• pp.2228-2236
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• 2002

The axial piston pump by which the mechanical energy is converted into hydraulic energy has been widely used in a press, a injection molding machine and construction equipments due to the high specific power compared to the electric power system. In this paper, the one-piece shoe holder spring of the axial piston pump to simplify its structure and reduce this manufacturing cost was designed and tested. The finite element analyses using the 3-D shell element and contact element were performed to determine the thickness, width and initial angle of the shoe holder spring. Also, the compressive tests of the shoe holder spring were performed and their results were compared with those of the finite element analysis. Also, the performance and endurance limit of axial piston pump with the shoe holder spring were tested and evaluated.

• Journal of the Institute of Electronics Engineers of Korea SC
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• v.46 no.1
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• pp.49-54
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• 2009

This paper proposes a new approach to provide RF communication channel and electric power transmission to overcome the weakness of conventional tests, which may cause several problems. When an RF communication device is used to communicate between launch vehicle and launch complex in stead of using harness umbilical, it may draw the simplicity of ground test equipments, cost-saving, and the reduction of test time. In addition, if an RF power transmission device is adopted to supply on-board power of launch vehicle, it can replace expensive on-board batteries, which may be degraded easily by the repeated charging and discharging processes.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2149-2151
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• 1999

This paper describes the impulse response characteristics of the grounding systems in power utility system. Several regulations regarding to electric power equipments, services and managements require that the groundings of class 1 ($E_1$) and class 2 ($E_2$) must be connected at the common point in grounding systems. In addition, the grounding for arrester ($E_{LA}$), which belongs to the grounding of class 1, should be connected at the same point. However, there is no method and position of common-connection at anywhere. In this work, when the impulse current was injected through the grounding conductor for arrester, the investigations measuring and analyzing potential rises induced at the common connection point and other grounding conductors were conducted. The experiments were carried out in the conditions of the grounding conductor of 25m long and the near or remote common connection from ground electrode. The lightning impulse current was applied so as to simulate the on-set of arrester due to lightning and/or switching surges.