• Title/Summary/Keyword: operation principle

Search Result 896, Processing Time 0.051 seconds

Asymmetry Components Reduction using Superconducting Fault Current Limiter Operation in Transient Period (비대칭 고장전류 저감을 위한 초전도 한류기 동작 분석)

  • Rhee, Sang-Bong;Kim, Chul-Hwan;Kim, Kyu-Ho;Kim, Jae-Chul;Hyun, Ok-Bae
    • Proceedings of the KIEE Conference
    • /
    • 2008.07a
    • /
    • pp.381-382
    • /
    • 2008
  • This paper presents a novel scheme for reducing an asymmetry current with SFCL (Superconducting Fault Current Limiter) operation during transient period, when a fault occurs in power systems. The main idea is installation an auxiliary SFCL with characteristics, which reduces the asymmetry fault current in first half cycle before the operating of main SFCL. For proper activities of SFCLs, the principle of asymmetry current nature is reviewed. A scheme of asymmetry components reduction with SFCL is then explained. The EMTP/ATPDraw model of SFCLs using MODELS language developed and simulated to verify the performance and effectiveness.

  • PDF

Education and Training Program using HANARO

  • Seo, Kyung-Won;Han, Eun-Young
    • Journal of Radiation Protection and Research
    • /
    • v.24 no.4
    • /
    • pp.231-233
    • /
    • 1999
  • This report will introduce the epitome about the subject, HANARO (Hi-flux Advanced Neutron Application Reactor designed by KAERI in early 1995) Utilization Education Training Program Development and Operation, which is one of the nuclear research basic expansion businesses executed from 1999. 12. to strengthen the usage of HANARO. This program consists of the basic reactor experiments program for university students who have specialty of nuclear and other engineering, and the special research education program for faculties from universities and researchers from industrial fields. Principle lessons are reactor operation, radioisotope production, neutron activation analysis, neutron radiography, radiation shield (health physics), nuclear fuel combustion measurement by gamma scanning arrangement, and CNS (Compact Nuclear Simulator) and so on.

  • PDF

Vibration and Dynamic Stability of Pipes Conveying Fluid on Elastic Foundations

  • Ryu, Bong-Jo;Ryu, Si-Ung;Kim, Geon-Hee;Yim, Kyung-Bin
    • Journal of Mechanical Science and Technology
    • /
    • v.18 no.12
    • /
    • pp.2148-2157
    • /
    • 2004
  • The paper deals with the vibration and dynamic stability of cantilevered pipes conveying fluid on elastic foundations. The relationship between the eigenvalue branches and corresponding unstable modes associated with the flutter of the pipe is thoroughly investigated. Governing equations of motion are derived from the extended Hamilton's principle, and a numerical scheme using finite element methods is applied to obtain the discretized equations. The critical flow velocity and stability maps of the pipe are obtained for various elastic foundation parameters, mass ratios of the pipe, and structural damping coefficients. Especially critical mass ratios, at which the transference of the eigenvalue branches related to flutter takes place, are precisely determined. Finally, the flutter configuration of the pipe at the critical flow velocities is drawn graphically at every twelfth period to define the order of the quasi-mode of flutter configuration.

TWO-SWITCH BOOST CHOPPER-BASED PFC RECTIFIER FOR ELECTRONIC BALLAST

  • Takhashi, Nobuo;Okutsu, Kenzo;Kato, Yoshito;Ohkita, Masaaki;Matsuyama, Makoto;Nakaoka, Mutsuo
    • Proceedings of the KIPE Conference
    • /
    • 1998.10a
    • /
    • pp.993-997
    • /
    • 1998
  • This paper presents a two-switch boost chopper with a sinewave current shaping and power factor correction scheme, which is applied for driving electronic ballast using high frequency resonant inverter. A working principle of the proposed one-converter type electronic ballast with power factor correction and active filtering schemes is described on the bases of the equivalent circuit of each operation mode, together with operation analysis. The steady-state performance evaluations of this electronic ballast are illustrated and discussed in experiment.

  • PDF

A Study on a High Frequency Ballast for Metal Halid Lamp (메탈핼라이드 램프용 고주파 전자식 안정기의 개발 연구)

  • Han, Soo-Bin;Park, Suck-In;Song, Eu-Gine;Jung, Hak-Kun;Jung, Bong-Man
    • Proceedings of the KIPE Conference
    • /
    • 2010.07a
    • /
    • pp.81-82
    • /
    • 2010
  • This paper suggests a high frequency operated electronic ballast. Operation frequency is sufficiently high above 250kHz for avoiding the acoustic resonance in metal halide lamp. The inverter composition and operation principle of ballast are described and verified by experiments.

  • PDF

Hierarchical Optimal Control of Non-linear Systems using Fast Walsh Transform (FWT를 이용한 비선형계의 계층별 최적제어)

  • Jeong, Je-Uk;Jo, Yeong-Ho;Im, Guk-Hyeon;An, Du-Su
    • The Transactions of the Korean Institute of Electrical Engineers D
    • /
    • v.49 no.8
    • /
    • pp.415-422
    • /
    • 2000
  • This paper presents a new algorithm for hierarchical optimal control of nonlinear systems. The proposed method is simple because the solutions are obtained by only exchanging informations of coefficient vector based on interaction prediction principle and FWT(fast Walsh transform) in upper and lower level. Since we solve two point boundary problem with Picard's iterative method and the backward integral operational matrix of Walsh function to obtain the optimal vector of each independent subsystem, the algorithm is simple and its operation is fast without inverse matrix and kronecker product operation. In simulation, the proposed algorithm's usefulness is proved by comparison with the global optimal control methods.

  • PDF

A Case Report of Acquired Nonmalignant Tracheoesophageal Fistula (후천성 비종양성 기관식도루;수술 치험1례)

  • 윤정섭
    • Journal of Chest Surgery
    • /
    • v.25 no.8
    • /
    • pp.800-805
    • /
    • 1992
  • Acquired, nonmalignant tracheoesophageal fistula is an uncommom and difficult problem to manage. The most commom cause is a complication of endotracheal or tracheostomy tubes. Most are diagnosed while patients still require mechanical ventilation. The principle of treatment is two stage operation. First, new tracheostomy tube is placed so that the baloon is below the fistula, and gastrostomy and feeding jejunostomy are made for the drainage and feeding. Finally after weaning from the mechanical ventilation, tracheal resection and reconstruction are made, and the esophageal defect is closed in two layers and a viable strap muscle interposed into the two suture site to prevent recurrence. Recently, we experienced a case of acquired nonmalignant tracheoesophageal fistula which was developed during mechanical ventilation. She was successfully treated with the above two stage operation.

  • PDF

Principles and Implication of Rail Infrastructure Charging in Advanced Countries (철도 선진국의 선로사용료 현황과 그 시사점)

  • Lim, Chai-Sung
    • Journal of the Korean Society for Railway
    • /
    • v.11 no.3
    • /
    • pp.263-271
    • /
    • 2008
  • This article considers how the rail track charges of the advanced countries are performed and derived political implication to Korail. In case of North America and Japan, rail track charges are being decided to collect the infrastructure maintenance cost. In European countries, the separation of infrastructure and operation is realized and the railroad track charges are based on MC+ principle. On the other hand, Korail is paying construction cost of KTX as well as maintenance cost in Korea. As for this, railroad reform including rail track charging should be reconsidered.

Implementation of One-Cycle Control for Switched Capacitor Converters

  • Yang, Lei;Zhang, Xiaobin;Li, Guann-pyng
    • Journal of Power Electronics
    • /
    • v.16 no.6
    • /
    • pp.2057-2066
    • /
    • 2016
  • An extension of the one-cycle control (OCC) method for switched-capacitor (SC) converters is proposed in this paper, featuring a fast dynamic response, wide line and load operation ranges, and simplicity in implementation. To illustrate the operation principle of this nonlinear control method and to demonstrate its simplicity in design, a dual-phase unity gain SC converter is examined. A new control loop based on the charge balance in a flying capacitor is formulated for the OCC technique and implemented with a 15W dual-phase unity gain SC converter on a circuit board for control verification. The obtained experimental results show that external disturbances can be rejected in one switching cycle by the OCC controlled SC converter with good line and load regulations. When compared to other control methods, the proposed nonlinear control loop exhibits superior dynamic performance in suppressing input and load disturbances.

Operation characteristics of fast pulse generator using a 2-stage magnetic switch (2단 자기스위치를 사용한 고속 펄스발생기의 동작 특성)

  • 김복권;권순걸;서기영;이현우
    • Journal of the Korean Institute of Telematics and Electronics B
    • /
    • v.33B no.10
    • /
    • pp.139-147
    • /
    • 1996
  • In this study a two-stage fast pulse generaor using magnetic switches is proposed. The scheme consist of a switch, an inductor and two pairs of capacitor and saturable inductors, a linear transformer. The basic principle and the operation are described using a set of given parameters. The main issue of the magnetic pulse genration scheme is the system efficiency. This study focuses on the system efficiency improvement using magnetic switches. The voltage compression ratio, energy transfer with respect to core area are investigated. The output voltage and transferred energy as a function of input voltage are also included. Also, an analysis and experiments are performed to verify the porposed topology by implementing a 10[J] class experimental circuit. The efficiency of the transferred energy a tload side is 82%.

  • PDF