• Proceedings of the KIEE Conference
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• 1997.07e
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• pp.1791-1793
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• 1997

Since Korea was initiated a industrialization, many transmission lines have been installed to meet the increasing demand for the electric power. In large city, underground transmission lines were widely installed because of the environmental issue. But there have been appeared many failures on the lines, such as the external scar of cable, a fire in the culvert, overheating of cable, and so on. There have been many studies to monitor them and improve the reliability of the power supply. As a method monitoring the lines, a DTS(Distributed Temperature Sensor) system is developed and applied. This system monitors the lines and predicts the failures, using a optical fiber sensor. This paper describes this DTS system and its application for the underground transmission lines.

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.2014-2016
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• 2000

In order to meet recent increasing demand for electric power in large cities, plans are being made to introduce 345kV lines into large urban areas. Up to now, OF cables have been used for 345kV fines, but nowadays XLPE insulated cables are preferred as they are easier to maintain due to phenomenal advances in plastic insulation technology, therefore cable manufacturing companies are trying to improve the performance and reliability of UHV CV cables and their accessories. For the purpose, our company has developed facilities for testing UHV cables. In this paper, we describes the methodology adopted for the design and development of a test termination, conducted the electrical test of UHV cables. Based on detailed analytical studies for electrical field distribution, the internal electrical design for the testing end has been carried out.

• 한국연소학회:학술대회논문집
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• 2015.12a
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• pp.185-188
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• 2015

An experimental study on downwardly and upwardly spreading flames over slanted electrical wire, which is insulated by Polyethylene(PE), was conducted with applied AC electric field. The result showed that downwardly and upwardly spreading flames with angle of inclination leaned toward burnt side and unburned side, respectively. With applied AC electric fields, size of downwardly spreading flame decreased slightly and that of upwardly spreading flame increased significantly. Flame spread rate showed various trends in terms of inclination, applied voltage and frequency.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.615-617
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• 1993

Recently, the demand of electric power has increased remarkably in densely populated cities in Korea. Various method to increase the power transmission capability of underground cable lines has been investigated. In this paper presents the study of inner cool ins cable system for larger power transmission capability. It is also shown that designed inner cooling cable and their system proves more economic than conventional type cables.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.621-623
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• 1993

This paper describes the research in condenser cone of sealing-end for 154kV oil-filled underground cable. We conducted the design based on the results of electric field analysis by electrostatics theory and FEM. In case that condenser cone type EB-A was compared with bell mouth type EB-A, the results of the AC and lightening impulse voltage test showed improvment of 10 percents.

• Fire Science and Engineering
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• v.24 no.4
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• pp.104-108
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• 2010

This paper describes electrical fire on electric pad using carbon type hot wires. A carbon type hot wires electric pad is virtually impossible to connect hot wire as a method of electrical welding or soldering. In order to connect between hot wires, that has to splice carbon type material connector. If junction of hot wires was occurrence of poor connection on electric pad, it increase contact resistance on this junction point. With increasing contact resistance, junction of hot wires on electric pad generates local heating and finally leads to electrical fire. In this paper, we analyzed shape of damage in hot wires caused by electrical local heating and investigated fire cause on electric pad using by carbon type hot wires.

• Journal of the Korean Society of Combustion
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• v.19 no.4
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• pp.1-7
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• 2014

An experimental study on downwardly spreading flame over slanted electrical wire, which is insulated by Polyethylene (PE), was conducted with applied AC electric fields. The result showed that the flame spread rate decreased initially with increase in inclination angle of wire and then became nearly constant. The flame shape was modified significantly with applied AC electric field due to the effect of ionic wind. Such a variation in flame spread rate could be explained by a thermal balance mechanism, depending on flame shape and slanted direction of flame. Extinction of the spreading flame was not related to angle of inclination, and was described well by a functional dependency upon the frequency and voltage at extinction.

• Journal of Electrical Engineering and Technology
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• v.12 no.2
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• pp.858-864
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• 2017

This study aims to restrain free conducting wire-type particles which are commonly and dangerously existing within DC gas-insulated transmission lines. A realistic platform of a coaxial cylindrical electrode was established by using a high-speed camera and a partial discharge (PD) monitor to observe the motion, PD, and breakdown of these particles. The probabilities of standing or bouncing, which can be affected by the length of the particles, were also quantitatively examined. The corona images of the particles were recorded, and particle-triggered PD signals were monitored and extracted. Breakdown images were also obtained. The air-gap breakdown with the particles was subjected to mechanism analysis on the basis of stream theory. Results reveal that the lifting voltage of the wire particles is almost irrelevant to their length but is proportional to the square root of their radius. Short particles correspond to high bouncing probability. The intensity and frequency of PD and the micro-discharge gap increase as the length of the particles increases. The breakdown voltage decreases as the length of the particles decreases.

• Proceedings of the KIEE Conference
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• 2001.07c
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• pp.1768-1770
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• 2001

EHV power cables can take any damage during shipping, transportation, handling, storage and installation. As the damage influences a reliability of the power cable system in the short and long periods, field tests have been required, for installers, to confirm the reliability of an installed system and, for utilities, to make sure the compatibility of an installed system. Of field tests, a HV withstand test for the cable insulation has been performed to check the soundness of the insulation. For EHV XLPE power cables, the test has been done by applying a specified d.c voltage till lately. But as some problems with the d.c test is emphasized and the equipment for the a.c test is improved, the a.c test is considered positively as an after-installation test. This paper describes the recent trends of the a and its recent application in the field.

• Journal of Power Electronics
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• v.16 no.5
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• pp.1928-1938
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• 2016

The three-phase four-wire shunt active power filter (APF) is an effective method to solve the harmonic problem in three-phase four-wire power systems. In addition, it has two possible topologies, a four-leg inverter and a three-leg inverter with a split-capacitor. There are some studies investigating DC-link voltage control in three-phase four-wire APFs. However, when compared to the four-leg inverter topology, maintaining the balance between the DC-link upper and lower capacitor voltages becomes a unique problem in the three-leg inverter with a split-capacitor topology, and previous studies seldom pay attention to this fact. In this paper, the influence of the balance between the two DC-link voltages on the compensation performance, and the influence of the voltage balance controller on the compensation performance, are analyzed. To achieve the balance between the two DC-link capacitor voltages, and to avoid the adverse effect the voltage balance controller has on the APF compensation performance, a new DC-link voltage balance control strategy for the three-phase four-wire split-capacitor APF is proposed. Representative simulation and experimental results are presented to verify the analysis and the proposed DC-link voltage balance control strategy.