• Proceedings of the KIEE Conference
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• 1998.07a
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• pp.302-304
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• 1998

Self magnetic field in a Bus bar usually degrades the critical current in it. Actually the total critical current of a Bus bar is not the same as the sum of total critical current of each stacked HTS tape. This is due to the self field effects in a bus bar. To reduce the degradations of critical current in a bus bar, we need to analyze the self field distributions in a bus bar. Conceptually, by rearranging the each stacked tapes, the self field effects can be minimized. In this paper, we calculate the self magnetic field distributions across a bus bar analytically, with the variations of the relative angle of the two conductors in a go-and-return pair. As a result, we suggest that the optimum relative angle exist which minimize the self field effect in a bus bar.

• Progress in Superconductivity and Cryogenics
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• v.2 no.2
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• pp.20-25
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• 2000

A CICC type superconducting bus-line electrically connecting a superconducting magnet to a power supply is cooled down to low temperature under the external magnetic field during operation. The thermal contraction during the cooling may be constrained by the supports which are installed to protect the bus-line from Lorenz magnetic forces. This constrained contraction causes thermal stresses in the bus-line to release thermal contraction. The minimum stress conditions in the bus-line may be optimized by controlling the supporting arrangement considering the thermal contraction and the external field. The analytical method to find optimal supports arrangement was suggested by using the beam theory, and numerical calculation using commercial code was performed to verify the suggested analytical optimization method.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.50 no.10
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• pp.509-516
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• 2001

Isolated phase bus(IPS) has a special structure for carrying large current generated by a generator to a main transformer. In the analysis of IPB, the understanding of the magnetic field distribution generated by large current is important. Especially, while the bus conductor current is flowing, almost same amount of current as bus conductor current is induced in the enclosures under the influence of time varying magnetic field, and therefore the large electric loss and the deterioration of insulating capability might occur due to Joule heating effect. Hence for the optimal design of IPB satisfying the condition to minimize the loss, the accurate analysis of magnetic field distribution and the eddy current characteristics of three phase isolated phase bus have been investigated. In the analysis of time varying magnetic field, instead of finite difference method(FDM) which is generally used, finite element method with phasor concept is investigated under the assumption that the bus current is purely sinusoidal. The characteristics is studied along the phase angle by comparing the effect of eddy current on the magnetic field distribution with the case that eddy current is not considered, and also the effect of material, thickness and radius of enclosure on the eddy current distribution is discussed.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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• pp.318-322
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• 2014

A kind of field bus called Actuator and Sensor interface bus(AS-i) was designed in this paper. The configuration of AS-i network system used Application Specific Integrated Circuit(ASIC) SAP5S chip and PLC S7-200 station, which included CPU 224 and AS-i master module CP 243-2. We also created an example program for PLC S7-200 to control AS-i network. The fire and smoke detection system was made with AS-i network system that was designed. This system had got more advantages than other system such as number of stations, easy installation, wide working area, etc. And designed system can be used as a partner network for higher level field bus networks.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.61 no.4
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• pp.220-224
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• 2012

The analysis on the bus bar effect is conducted to develop a cost effective 24kV/2,000A switchgear. The temperature enclosures and bus bars could rise due to several heat sources such as eddy current losses and copper losses. Therefore, a study on the characteristics of the electric field intensity and electromagnetic loss according to the bus bar size in a bus bar compartment is essential to design a electrically reliable high voltage switchgear. It is investigated that the electromagnetic influence to the temperature rising and the dielectric stability according to various bus bar sizes by using finite element method(FEM). The electric field intensity and electromagnetic loss according to various bus bar sizes are calculated to design a reliable and a high voltage switchgear. As results, it is found that the electromagnetic loss and the dielectric stability of bus bar could be determined by a bus bar size. It means that a cost effective 24kV/2,000A high voltage switchgear could be developed by selecting the proper size of a bus bar. Also, it is recognized that the electromagnetic characteristics according to various bus bar sizes in order to design an electrically stable high voltage switchgear when the enclosure size is determined as a fixed value. Futhermore, studies on the various nominal voltage class and bus bar sizes will be conducted to develop a cost effective high voltage switchgear.

• Proceedings of the KIEE Conference
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• 2001.07b
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• pp.1266-1268
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• 2001

ProfiBus provides real-time data communication among field devices in the EMU (Electrical Multiple Unit) and TCMS (Train Control Monitoring System). This paper presents an adapt to Train Communication Network for EMU using ProfiBus DP(Decentralized Periphery) mathod, which is the layer 2 DDLM(Direct Data Link Mapper) protocol of ProfiBus.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.50 no.6
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• pp.279-286
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• 2001

A load modeling, micro method, is performed by component load modeling, load composition rate estimation and aggregation of component load model, etc. The load model obtained from this process must be applied to actual load bus to verify it and to get reliable load model. But it is difficult to apply every load bus due to al lot of load buses and complex experiment. This paper proposed the field test method in load bus to verify the load modeling. For appropriate field test, representative load buses are selected by the proposed algorithm considering the composition rate of user category in all load buses. The field tests were performed at selected load buses to obtain load characteristics of bus by time and seasonal without blackout. The results of measurement and analysis are presented in detail.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.675-676
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• 2006

This paper shows the temperature rise of the high voltage GIS bus bar. The temperature rise in GIS bus bar is due to Joule's losses in the conductor and the induced eddy current in the tank. The power losses of a bus bar calculated from the magnetic field analysis are used as the input data for the thermal analysis to predict the temperature. The required analysis is a couple-field Multiphysics that accounts for the interactions between three-dimensional AC harmonic magnetic and fluid fields. The heat transfer calculation using the fluid analysis is done by considering the natural convection and the radiation from the tank to the atmosphere. Consequently, because temperature distributions by couple-field Multiphysics (coupled magnetic-fluid) have good agreement with results of temperature rise test, the proposed couple-field Multiphysics technique is likely to be used in a conduction design of the single-pole and three pole-encapsulated bus bar in CIS..

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.201-205
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• 2001

This paper presents the load modeling process and bus load models for KEPCO power system. At first, load devices commonly used in KEPCO power systems were selected, and tested for measuring the voltage and frequency sensitivity of active and reactive power. From this test, about 40 voltage and frequency dependent load models have been obtained. The bus load composition rate for KEPCO power system has been determined using the various recent surveys and papers in order to develop the load model for a power system bus. To verify the accuracy of developed bus load models, the field test for measuring active and reactive power according to artificial variation of the bus voltage was performed at 8 substations for spring summer, autumn, winter cases. With data of this seasonal field test, more reliable bus load models for KEPCO power systems were developed.

• Journal of Advanced Navigation Technology
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• v.21 no.4
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• pp.386-393
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• 2017

Field programmable gate arrays (FPGAs) are widely used for verification in chip development. In order to verify the circuit programmed to the FPGA, data must be input to the FPGA. There are many ways to communicate with a chip through a PC and an external board, but the simplest and easiest way is to use a universal asynchronous receiver/transmitter (UART). Most recently, most circuits are designed to be internally connected to the advanced microcontroller bus architecture (AMBA) bus. In other words, to verify the designed circuit easily and simply, data must be transmitted through the AMBA bus through the UART. Also the AMBA bus has been available in various versions since version 4.0 recently. Advanced peripheral bus (APB) is suitable for simple testing. In this paper, we design a circuit for UART-to-APB interface. Circuits designed using Verilog-HDL were implemented in Altera Cyclone FPGAs and were capable of operating at speeds up to 380 MHz.