• Title/Summary/Keyword: Neutral

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Current Limiting Characteristics of Superconducting Fault Current Limiter for Reduction of Unsymmetrical Fault Current in a Three-Phase Power System (삼상전력계통의 비대칭고장전류 저감을 위한 초전도한류기의 전류제한특성)

  • Kim, Min-Yeong;Lim, Sung-Hun;Hwang, Jong-Sun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.03b
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    • pp.8-8
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    • 2010
  • In this paper, the limiting characteristics of the fault current in a power system with a superconducting fault current limiter(SFCL) applied into neutral line of main transformer in a distribution power line were analyzed. The SFCL applied into the neutral line of main transformer power system can limit the unsymmetrical fault current from the single-line ground fault or the double-line ground fault. In addition, it could be decreased a number of SFCL and a load. This method could be expected to reduction of a power loss in the neutral line, because of a neutral line current is zero in ordinary times.

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Separation of Ether-Soluble Neutral Extract of a Commercial High-Grain Feed Stimulating Hay Intake in Cattle

  • Shahjalal, M.;Dohi, H.;Kosako, T.;Hayashi, Y.
    • Asian-Australasian Journal of Animal Sciences
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    • v.13 no.2
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    • pp.188-191
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    • 2000
  • Appetite stimulant ether-soluble neutral extract of a high-grain compound feed was separated into four fractions with an open column of silica gel chromatograph using four carrier solutions containing n-pentane and diethyl ether as 100:0 (Fraction A), 90:10 (Fraction B), 75:25 (Fraction C) and 0:100 (Fraction D). The stimulative effects of the fractions were examined by comparing the intake of hay (with or without the fractions) in two-choice test bioassays with cattle. The Fractions A, B and C of the neutral extract stimulated (p<0.05) hay consumption in cattle, whereas Fraction D had no effect on selective feeding when compared with the control fraction. Furthermore, Fractions A, B and C had higher (p<0.05) feeding stimulative indices (FSI) than that of the Fraction D. The results suggest that chemical stimulants to increase palatability of hay are present in the neutral Fractions A, B and C of high-grain concentrate.

An Integrated Translation of Nuclear Power Plant Design Data ftom Specification-driven Plant Design Systems to a Neutral Product Model (사양 기반 플랜트 설계 시스템에서 생성된 원자력 플랜트 설계 데이터의 중립 모델로의 통합 변환)

  • Mun, Du-Hwan;Yang, Jeong-Sam;Han, Soon-Hung
    • Korean Journal of Computational Design and Engineering
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    • v.14 no.2
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    • pp.96-104
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    • 2009
  • It gradually becomes important to study on how to efficiently integrate and manage plant lifecycle data such as 2D schematic and 3D solid data, logical configuration data, and equipment specifications data. From this point of view, converting plant design data from various systems into neutral data independent from any commercial systems is one of important technologies for the operation and management of plants which usually have a very long period of life. In order to achieve this goal, a neutral model for efficient integration and management of plant data was defined. After schema mapping between one of specification-driven plant design systems and the neutral model was performed, a plant data translator is also implemented according to the mapping result. Finally, by experiments with nuclear power plant design, the feasibility of the translator was demonstrated.

The Study of relation most suitable betweenPantograp interface And Neutral Section (전기철도 절연구분장치와 팬터그래프 인터페이스 최적화에 관한 연구)

  • Kim, In-Chol
    • 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.

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TECHNOLOGY-NEUTRAL NUCLEAR POWER PLANT REGULATION: IMPLICATIONS OF A SAFETY GOALS- DRIVEN PERFORMANCE-BASED REGULATION

  • MODARRES MOHAMMAD
    • Nuclear Engineering and Technology
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    • v.37 no.3
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    • pp.221-230
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    • 2005
  • This paper reviews the pivotal phases of the evolution of the current technology-dependent nuclear power safety regulation in the United States. Understanding of this evolution is essential to the development of any future regulatory paradigm, including the technology-neutral regulatory approach that the U.S. Nuclear Regulatory Commission (NRC) has recently embarked on to develop. The paper proposes and examines the implications of a predominately rationalist and best-estimate probabilistic regulatory framework called safety goals-driven performance-based regulation. This framework relies on continuous assessment of performance of a set of time-dependent safety-critical systems, structures and components that assure attainment of a broad set of technology-neutral protective, mitigative, and preventive goals. Finally, the paper discusses the steps needed to develop a corresponding technology-neutral regulatory system from the proposed framework.

Hyper Neutral Beam System for Damage Free Deposition of Indium-Tin Oxide Thin Films at Room Temperature

  • Yoo, Suk-Jae;Kim, Dae-Chul;Kim, Jong-Sik;Oh, Kyoung-Suk;Lee, Bong-Ju;Choi, Soung-Woong;Park, Young-Chun;Jang, Jin-Nyoung;Hong, Mun-Pyo
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08a
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    • pp.190-192
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    • 2007
  • A neutral beam system has been developed to produce hyperthermal neutral beams composed of indium, tin, and oxygen atoms. Using these hyper thermal neutral beams with energies in the range of tens of eV, high quality indium-tin oxide (ITO) thin films have been obtained on glass substrates at room temperature. The optical transmittance of the films is higher than 85% at a wavelength of 550 nm and the electrical resistivity is lower than $1{\times}10^{-3}{\Omega}cm$.

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Neutral Reference Model for Engineering Change Propagation in Global Top-down Modeling Approach

  • Hwang, Jin-Sang;Mun, Du-Hwan;Han, Soon-Hung
    • International Journal of CAD/CAM
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    • v.7 no.1
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    • pp.81-89
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    • 2007
  • As the modular production is an important issue in globalized manufacturing industries, sub modules or parts of the final product are provided by many suppliers. Some part suppliers design their own products for themselves. In some cases, part supplier may provide the same type product to multiple 1-tier companies. Because all suppliers and 1-tier companies can not use the same CAD system in general case, the engineering change in the CAD model of one company could not propagate to related CAD models of other companies directly. Although they use the same CAD system, it is hard to share their CAD model with each other because of company security policy. In this paper, the neutral reference model, which consists of the neutral skeleton model and the external reference model, is proposed to apply a global top-down modeling approach to collaborating companies.

A study on the vowel extraction from the word using the neural network (신경망을 이용한 단어에서 모음추출에 관한 연구)

  • 이택준;김윤중
    • Proceedings of the Korea Society for Industrial Systems Conference
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    • 2003.11a
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    • pp.721-727
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    • 2003
  • This study designed and implemented a system to extract of vowel from a word. The system is comprised of a voice feature extraction module and a neutral network module. The voice feature extraction module use a LPC(Linear Prediction Coefficient) model to extract a voice feature from a word. The neutral network module is comprised of a learning module and voice recognition module. The learning module sets up a learning pattern and builds up a neutral network to learn. Using the information of a learned neutral network, a voice recognition module extracts a vowel from a word. A neutral network was made to learn selected vowels(a, eo, o, e, i) to test the performance of a implemented vowel extraction recognition machine. Through this experiment, could confirm that speech recognition module extract of vowel from 4 words.

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Neutral-point Potential Balancing Method for Switched-Inductor Z-Source Three-level Inverter

  • Wang, Xiaogang;Zhang, Jie
    • Journal of Electrical Engineering and Technology
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    • v.12 no.3
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    • pp.1203-1210
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    • 2017
  • Switched-inductor (SL) Z-source three-level inverter is a novel high power topology. The SL based impedance network can boost the input dc voltage to a higher value than the single LC impedance network. However, as all the neutral-point-clamped (NPC) inverters, the SL Z-source three-level inverter has to balance the neutral-point (NP) potential too. The principle of the inverter is introduced and then the effects of NP potential unbalance are analyzed. A NP balancing method is proposed. Other than the methods for conventional NPC inverter without Z-source impedance network, the upper and lower shoot-through durations are corrected by the feedforward compensation factors. With the proposed method, the NP potential is balanced and the voltage boosting ability of the Z-source network is not affected obviously. Simulations are conducted to verify the proposed method.

The Effect by Grounding Resistance of the ground Fault in the 22.9[kV] Multi-ground Distribution System (22.9[kV] 다중접지 배전계통에서 고장전류의 접지저항 영향 분석)

  • Jung, Kum-Young;Choi, Sun-Kyu;Shim, Keon-Bo;Kim, Kyung-Chul
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.24 no.10
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    • pp.85-89
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    • 2010
  • During a ground fault the maximum fault current and neutral to ground voltage will appear at the pole nearest to the fault. Distribution lines are consisted of three phase conductors, an overhead ground wire and a multi-grounded neutral line. In this paper phase to neutral faults were staged at the specified concrete pole along the distribution line and measured the ground fault current distribution in the ground fault current, three poles nearest to the fault point, overhead ground wire and neutral line. A effect by grounding resistance of poles of ground fault current in the 22.9[kV] multi-ground distribution system. by field tests.