• Proceedings of the KIEE Conference
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• summer
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• pp.233-235
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• 2004

Operation of wind turbines has impacts on the voltage quantity at the connected electricity network. Increasing penetration of wind energy makes necessary to study the power quality regarding voltage variations(sag, swell, interruption) and presence of harmonics in the id. This paper investigates the voltage quality of low voltage customers connected to wind generation system. To study the influences of wind power generation to low voltage power system, voltage data are collected in three house using PQM(Power Quality Monitoring) equipment during one month and analyzed regarding voltage variation and harmonics

• Proceedings of the KIEE Conference
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• 2001.05a
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• pp.316-318
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• 2001

Occasionally, equipment in a distribution system fails due to damage from weather, vandalism, or other causes. In addition, it is recommended practice to have some way in which maintenance or replacement of every element in a system can be performed without causing lengthy interruption of electrical service to the customers it feeds. Thus, alternate sources, paths, and configurations of service must be planned so that both failures and maintenance do not affect customer service beyond a reasonable amount. In some cases, planning for alternate routes of service during equipment outages or emergencies -- will be the major aspect influencing selection of a feeder's capacity, type of route, or layout. We want to know the relationship between molt-dividing multi-connection and distribution reliability for contingency support considerations.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.6-9
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• 2009

Recently, there have been studied the importance of the grounding system, as electrical equipments installed in the building, such as intelligent building. The object of grounding of electrical facilities is to protect human and machine damage from the power supply interruption high voltage by use of the accident current dissipating into the ground. In this paper, we is proposed to design of grounding system with economical efficiency in electric rolling stocks facilities. To make efficient ground, ground potential rise must be controlled in the way of overall lowering and evenness instead of independent grounding method with respect to electrical facilities.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.9 no.3
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• pp.401-409
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• 1997

The long term drag reduction characteristics of Habon-G solution were investigated in the KIER pilot-scaled district heating simulation system. Test runs were implemented for 30 days without interruption. Pressure drop, flow rate and power consumption of surfactant (Habon-G) solution were regularly observed and compared with those of plain water. The experimental results suggest that the surfactant can be effectively applied to the DH transmission system for considerably long period wthout significant loss of its drag reduction capability even though the concentration of the additive may gradually decrease in the first stage of the experiment because of absorption.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.91-92
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• 2008

The rating of a circuit breaker depends not only on the interrupting current but also on a transient recovery voltage (TRV). To achieve a successful interruption, the circuit breaker must withstand the TRV. A superconducting fault current limiter (SFCL) is a device that limits the fault current fast and effectively without having high impedance during normal operation of the power system. Therefore, we studied the influence of the TRV according to the application of a resistive type SFCL in distribution system. This paper analyses the influence of the TRV for various application position of the resistive SFCL. The distribution system and the resistive SFCL were modeled by using EMTP-RV (Electromagnetic Transient Program - Restructured Version)

• Proceedings of the KIEE Conference
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• 2002.11d
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• pp.325-329
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• 2002

This paper is intended as an investigation of the interface between Neutral section insulators and pantograph interface. Neutral section insulators are installed at the boundary between AC catenary system and DC catenary system, which should provide electrical insolation between two different catenary systems and pass the trains without interruption. As the number of the pantographs installed on the train increased, which is necessary for the VVVF inverter drive trains introduced in recent years, there occurs an serious aspects of the interaction between pantographs and Neutral section insulators. These effects hinder the automatic switch operation of MCB(Main Circuit Breaker) after passing through the section insulators, and lead to the extra-ordinary wear of FRP insulator material of section insulators. Countermeasures in terms of the interface between the Neutral secton insulators and electric collection system of train are provided too.

• Proceedings of the KIEE Conference
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• 1995.07b
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• pp.754-757
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• 1995

This system can detect a ground fault point or a bad insulated line by measuring a power plant DC feeder insulation resistance at the uninterruptible power status. And when the power plant DC feeder with low frequency AC signal has a ground fault, this measuring system can keep recording of its ground fault current and phase checked by Z.C.T. Therefore the power plant could protect a unexpected service interruption.

• International Journal of Railway
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• v.3 no.3
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• pp.106-112
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• 2010

Accidents at level crossing have large portion on train accidents, and causes economical loss by train delay and operational interruption. Various safety equipments are employed to reduce the accident at level crossing, but existing warning device, and crossing barrier are simple train-oriented protection equipments. In this paper, intelligent railway level crossing system is proposed to prevent and reduce accidents. For train driver's prompt action, image of level crossing and obstacle warning message are continuously provided to train driver through wireless communication in level crossing control zone. Obstacle warning messages, which are extracted by computer vision processing of captured image at level crossing, are recognized by train driver through message color, flickering and warning sound. It helps train driver to decide how to take an action. Meanwhile, for vehicle driver's attention, location and speed of approaching train are given to roadside equipments. We identified the effect of proposed system through test installation at Sea train and Airport level crossing of Yeong-dong line.

• The Transactions of the Korean Institute of Electrical Engineers A
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• v.51 no.1
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• pp.7-14
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• 2002

In power system study, relibility assessment has been an important topic during past several decards because sudden power interruption can bring about enormous economic loss. although the size of a substation is smaller than that of generation system or transmission system, switching actions after fault(s) make reliability assessment of substation rather complex situations such as switching actions easily and permit various probability distributions in describing substation elements. Despite this ability of Monte Carlo simulation, one-parameter exponential distribution is still popular in this reliability assessment. This paper examines the characteristics of several two-parameter probability distributions, and offers new parameter decision rule based on average and variance of the target to be modelled. In case study, this paper shows the profits by using Weibull distribution which is one of two-parameter probabilistic distributions instead of exponential one.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.61 no.1
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• pp.162-167
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• 2012

In power quality monitoring, it is very important to detect disturbances (sag, swell, transient, and interruption) accurately. In this paper, a detection method for power quality disturbances by combining the filter bank system and adaptive filter is proposed. To decompose power signal, binary tree structured filter bank system is designed. In the filter bank system, the fundamental filter bank(QMF bank) is used as a module in each decomposing level. An adaptive filter is used to improve the detection accuracy of disturbances for each subband signal. In the adaptive filter, the measure of estimated error change is used to detect singular points of power quality disturbances. Computer simulations were performed on synthetic signals which have disturbances to assess the performance of the proposed method.