• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.6
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• pp.137-144
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• 2002

Low voltage circuit breakers which interrupt rapidly and raise the reliability of power supply are widely used in power distribution systems. In the paper, it has been investigated how much interrupting capability is improved by correcting the shape of the contact system in molded case circuit breaker(below MCCB), especially arc runner. Prior to the interrupting testing, it is necessary for the optimum design to analyze electromagnetic forces on the contact system generated by current and flux density. This paper presents both our computational analysis and test results on contact system in MCCB.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.4
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• pp.814-819
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• 2010

This study proposes the antenna circuit design for the transmitting wireless power, the development of the RF non-contact type Dosimeter. That is, the study designed the optimization and numerical analysis of the antenna circuit for the antenna design of 13.56MHz over the frequency bands for transmitting wireless power. We studied the needed items in the existing RF type Dosimeter with battery to implement the wireless power non-contact Dosimeter within the battery. We compared to the real measurement value as calculating the value of the inductance and capacitance through the numerical analysis for the antenna LC resonance using the theory of the electromagnetic induction method. This method to drive low power is designed to simplify the circuit and to improve the efficiency of the rectifier. We convince our research contributes not only to understand the simplified circuit and miniaturization, but also to help the design and application technology of the wireless power transmit system which is received power supply with wireless.

• Proceedings of the KIEE Conference
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• 1997.07a
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• pp.244-246
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• 1997

This paper is to analyze the Premature Quench characteristics of a rotating magnet type superconducting fluxpump and consider the method of detecting and protecting this premature quench. Practically, there is contact resistance between the fluxpump and the load, namely the S.C. magnet. The thermal increase due to the contact resistance cause the premature quench before the charging current amounts to the critical current of S.C magnet. Therefore, this paper is devoted to solving the heat equation on contact region using cylindrical coordinates and to calculating the rate of thermal increase during the current is pumped up. Doing so, the predictive value of the maximum pumping current is obtained. It has been verified that the results of simulation are coincident with those of experiment. It must be considered essentially to minimize the contact resistance in designing the S.C fluxpump system in order to protect the premature quench and improve the maximum pumping current.

• Proceedings of the KSR Conference
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• 1998.11a
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• pp.296-301
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• 1998

Pentagraphs are used to supply electric power to train via trolley lines. The higher train speed is, the higher voltage and current levels 8u. Since electric power is supplied with slinding contact, localized abrasion is inevitable. It is difficult and dangerous to measure their shape manually. Measurement system of pentagraph slider with ultrasonic processing has been reported. In this paper, measurement system with image processing is proposed. The system consists of CCD cameras, image grabber board, and PC operated on Windows'95. Image processing algorithms are presented and some results are illustrated.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.3052-3058
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• 2011

A high-speed train is the system that the electric power is supplied through the overhead contact line and drives motors. In this case that the de-wiring beteen the overhead contact line and the pantograph of a high-speed train, the occasion that smooth power supply is not accomplished occurs sometimes. If the de-wiring occurs, the arc discharge may damage the overhead contact line or the pantograph, and the falling-off in power quality may cause the damage and malfunctioning of motor block. This paper presents the methodology that the arc discharge by de-wring between overhead line and pantograph is discriminated through measuring the PT and CT in the vehicle, and measures the current collection characteristics for a high speed train.

• Proceedings of the KSR Conference
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• 2009.05a
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• pp.1431-1440
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• 2009

A subway in Seoul has had a major role of public transportation after the opening of Seoul Subway Line 1 on August 15, 1974 and it has reached 34.7% of the transportation of Seoul citizens. The extended length of the subway system suppled with DC power in Korea is about 500km. In this system, the devices which are proper for regenerative power system are being required because of changeover from old braking and ATS signal system to regenerative braking and ATO signal system. In this paper, we reviewed the safety standards for the insulated hangers in overhead contact line. These hangers which have depended on foreign imports are being developed in Korea considering ease of demand and supply and economic effects.

• Proceedings of the KIEE Conference
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• 2006.04b
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• pp.347-350
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• 2006

The high efficiency full-bridge LLC resonant converter using a contact-less transformer is proposed for the photovoltaic power generation system. For the series resonance with a series capacitor, the LLC resonant converter utilizes the leakage inductance and magnetizing inductance of a contact-less transformer. Unlike the conventional series resonant converter operated to the continuous resonant current at above resonance frequency, the proposed converter operates to the discontinuous resonant current at the narrow frequency control range below resonance frequency. Due to the discontinuous mode resonant current, the proposed converter can be achieved the zero voltage switching (ZVS) in the primary switches and the zero current switching (ZCS) in the secondary rectification diodes without any auxiliary circuit. In this paper, the experimental results of the proposed full-bridge LLC resonant converter using a contact-less transfonner are verified on the simulation based on the theoretical analysis and the 150W experimental prototype.

• Journal of the Korea Safety Management & Science
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• v.22 no.1
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• pp.1-8
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• 2020

Maintenance of power distribution facilities is a significant subject in the power supplies. Fault caused by deterioration in power distribution facilities may damage the entire power distribution system. However, current methods of diagnosing power distribution facilities have been manually diagnosed by the human inspector, resulting in continuous pole accidents. In order to improve the existing diagnostic methods, a thermal image analysis model is proposed in this work. Using a thermal image technique in diagnosis field is emerging in the various engineering field due to its non-contact, safe, and highly reliable energy detection technology. Deep learning object detection algorithms are trained with thermal images of a power distribution facility in order to automatically analyze its irregular energy status, hereby efficiently preventing fault of the system. The detected object is diagnosed through a thermal intensity area analysis. The proposed model in this work resulted 82% of accuracy of detecting an actual distribution system by analyzing more than 16,000 images of its thermal images.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.06a
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• pp.394-394
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• 2009

Owing to the increasing number of intelligent homes(or called Smart home), the corresponding cost is much higher. Low voltage circuit breakers are widely used in the intelligent homes to interrupt fault current rapidly and to assure the reliability of the power supply. The distribution of magnetic field induced by arc current in the contact system of molded case circuit breaker(hereafter MCCB) depends on the shape, arrangement, and kinds of material of arc runner. This paper is focused on understanding the interrupting capability, more specifically of the arc runner, based on the shape of the contact system in the current MCCB. The magnetic driving force was calculated by using the flux densities induced by the arc current, which are obtained by three-dimensional finite element method. There is a need to assure that the optimum design required to analyze the electromagnetic forces of the contact system generated by current and the flux density be present. This is paper present our computational analysis on contact system in MCCB.

• The Transactions of the Korean Institute of Power Electronics
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• v.23 no.1
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• pp.1-8
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• 2018

A problem exists in the conventional transportation cart applications, in which an external power supply with mechanical contact connection (bus bar connection) is required to drive the motor. Therefore, continuous effort for maintenance is required, aside from the expensive bus bar connector. To solve this problem, a self-electricity-generated transportation cart system without bus bar has recently been introduced. In this system, a battery needs to store the power of the generated wheel, and a boost converter, which converts the low battery voltage to high bus voltage to drive the motor inverter, is necessary. However, since the instantaneous large current required for starting the motor is supplied from the battery, a battery with large size and volume should be adopted to withstand this large current. In this study, a boost converter that can supply a large instantaneous current by using super Capacitor string is proposed. The proposed converter can be realized with a small size and volume compared with the conventional battery-fed boost converter. Operational principles, analysis, and design of the proposed converter are presented, and experimental results are provided to validate the proposed converter.