• Title/Summary/Keyword: Current test

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Delphi Study on Introduction of Practical Skills Test in National Examination for Nursing Licensure (간호사 국가고시의 문제점과 개선방안에 대한 전문가 집단 연구)

  • Lim, Nan-Young;Song, Jung-Hee
    • Journal of Korean Academy of Fundamentals of Nursing
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    • v.14 no.2
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    • pp.157-165
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    • 2007
  • Purpose: The purpose of this study was to investigate the plan to introduce a practical skills test as part of the national examination for nursing licensure. Method: The delphi method was used. The first set of data was collected by open questionnaire from universities and hospitals nationally. The second and third were collected by structured questionnaire. Results: The biggest problem for clinical Practice in nursing education was reported as the lack of opportunities for direct nursing practice. The biggest performance problem in job duties for novice nurses was reported as the lack of integrated problem solving skills in a clinical situation. The biggest problem with the current national examination was reported as the use memorizing solutions to test questions. It was suggested that the best plan to resolve problems with the national examination would be to develop test questions representative of the clinical setting and increase personnel in clinical education. About the introduction of a practical skills test as part of the national examination, 56.9% were in agreement and 38.5% disagreed. Conclusion: The current national examination has many problems when it comes to testing clinical competency. So, a practical skills test must be deferred to a future time. There are also many difficulties in presenting a real situation, therefore further research is needed in preparation for the introduction of a practical skills test.

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Design of the RLG Current Stabilizer for Attitude Control in the Satellite (저궤도 위성 자세제어용 RLG 전류 안정화 회로 설계)

  • Kim, Eui-Chan;Lee, Heung-Ho
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.1
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    • pp.98-101
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    • 2008
  • In this paper, we describe the RLG current stabilizer circuit for attitude control in the satellite. The RLG makes use of the Sagnac effect within a resonant of a HeNe laser. The difference between two discharge currents causes one of the gyro bias errors. The theoretical background and current stabilizer are introduced. It is verified that the circuit designed is applicable to the test of input voltage and temperature.

The Effect of Train Motion on Current Collection in High-speed Train

  • Kim, Jung-Soo
    • International Journal of Safety
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    • v.5 no.1
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    • pp.1-4
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    • 2006
  • The safety performance of the current collection system is evaluated by conducting a test run in which accelerometer and load cell signals are analyzed. It has been found that the current collection performance is strongly influenced by the train speed, with the major frequency components arising from the train traversing the span spacing and the 8.5 Hz component originating from the panhead resonance. The train acceleration is found to have significant influence on the span passing frequency but negligible effect on the resonant response.

Development of superconducting current limiting device used high-$T_{c}$ superconductor (고온초전도체를 이용한 전류제한장치의 개발)

  • 최명호;강형곤;유현수;박성진;한병성
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 1993.11a
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    • pp.35-38
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    • 1993
  • SCLD(supercondocting current 1imiting device) with YBaCuO superconductor was fabricated by the sol-gel and the doctor-blade method. Critical current density ($J_{c}$) and critical current ($I_{c}$) of the SCLD are 100.27 A/$cm^2$and 1A at 77K and the electrodes contact with SCLD by silver paste. The SCL was connected with test circuit in series. When apple iud current exceed critical current value of the SCLD in testing circuit, the SCLD ristricts the over current by generating resistance itself without delay. Resistance of SCLD increase lineary 0 to 1.6$\Omega$ in propotion to applied current above the critical current $I_{c}$.

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AR Model and LSQ Based Compensation Method for the Saturated Secondary Current of a Current Transformer (AR 모델 및 LSQ 기반 변류기 2차 전류 복원 기법)

  • Chang, Soo-Young;Lee, Dong-Gyu;Kang, Sang-Hee
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.55 no.6
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    • pp.221-226
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    • 2006
  • The current flowing though a power line is measured by a current transformer (CT). Since a CT is a kind of transformer, saturation of magnetic flux in the core may occur when a large primary current flows. This saturation makes the secondary current of a CT distorted and causes problems in the protection point of view. Because of the current distortion, a protection relay cannot collect the correct information showing how the primary power system changed. Consequently, the current distortion may cause the mal-operation or operation time delay of protective relay. In this paper, an algorithm based on AR model and LSQ is proposed to compensate the saturated CT secondary currents. Various test results indicate that the proposed algorithm can accurately compensate a severely distorted secondary current and is not affected by remanence.

Compensation for the Secondary Current of an Air-gapped Current Transformer (공극 변류기의 2차 전류 보상)

  • Kang, Yong-Cheol;Zheng, Tai-Ying;Jang, Sung-Il;Kim, Yong-Gyun;Park, Ji-Youn
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.57 no.2
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    • pp.149-154
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    • 2008
  • An air-gapped current transformer(CT) has been used to reduce a remanent flux in the core, particularly in the case of auto-reclosure. However, it causes larger transient, ratio and phase errors than the iron-cored CT because of the small magnetizing inductance. This paper proposes a compensation algorithm for the secondary current of the air-gapped CT during the fault conditions including auto-reclosure as well as in the steady-state. The core flux is calculated from the measured secondary current of the CT and inserted into the hysteresis loop to estimate the exciting current. Finally, the correct current is estimated by adding the measured secondary current to the estimated exciting current. Various test results clearly indicate that the proposed compensating algorithm can improve the accuracy of the air-gapped CT significantly and reduce the required core cross-section of the air-gapped CT significantly.

Control of Parallel Connected Three-Phase PWM Converters without Inter-Module Reactors

  • Jassim, Bassim M.H.;Zahawi, Bashar;Atkinson, David J.
    • Journal of Power Electronics
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    • v.15 no.1
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    • pp.116-122
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    • 2015
  • This paper presents a new current sharing control strategy for parallel-connected, synchronised three-phase DC-AC converters employing space vector pulse width modulation (SVPWM) without current sharing reactors. Unlike conventional control methods, the proposed method breaks the paths of the circulating current by dividing the switching cycle evenly between parallel connected equally rated converters. Accordingly, any inter-module reactors or circulating current control will be redundant, leading to reductions in system costs, size, and control algorithm complexity. Each converter in the new scheme employs a synchronous dq current regulator that uses only local information to attain a desired converter current. A stability analysis of the current controller is included together with a simulation of the converter and load current waveforms. Experimental results from a 2.5kVA test rig are included to verify the proposed control method.

A Study on Stress Corrosion Behaviors in Welded Zone of the API 5L-X65 Steel for Natural Gas Transmission (천연가스 수송용 API 5L-X65강 용접부의 부식거동에 관한 연구)

  • JO SANG-KEUN;SONG HAN-SEOP;KONG YOO-SIK;KIM YUONG-DAI
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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    • 2004.05a
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    • pp.401-407
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    • 2004
  • This study is on the constant-current stress corrosion test related to the load stress in welded zone and non-welded zone of high tensile strength steel for natural gas transmission. The surface corrosion pattern of the welded zone of API 5L-X65 specimens for natural gas transmission showed global corrosion and narrow pitting, and the pitting was increased by increasing the load stress. Initially, the average relative electrode potential and the average relative current of the high tensile strength steel for natural gas transmission specimens was decreased suddenly, and the average relative electrode potential was higher and the average relative current was lower in welded zone than base metal. and the average relative electrode potential was decreased by increasing the load stress, and the average relative current was somewhat increased by increasing the load stress. The corrosion rate was less in welded zone than base metal, and the corrosion rate was decreased by increasing the load stress.

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Corona Cage Simulation on Environmental Characteristics Caused by the Ion flow of Candidated Conductor Bundles for HVDC Overhead Transmission (초고압 직류 가공송전 후보 도체방식의 이온류 환경특성 코로나 케이지 모의시험)

  • Ju, Mun-No;Yang, Kwang-Ho;Lee, Dong-Il;Shin, Koo-Yong
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.10
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    • pp.1791-1795
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    • 2007
  • Small ions generated at conductor corona sources remain in the atmosphere until they recombine with ions of opposite polarity, attach to aerosols, or make contact with an object. Ion current density is major factor to design conductor configuration of DC overhead transmission line. Several techniques have been used to measure the ion current of HVDC overhead transmission line. In this study, the ion current density was measured by a plate electrode made of a metal flat board at DC corona cage. The sensitivity of the plate electrode is $0.156uA/m^2/V$. To obtain an useful database on corona discharge, it is necessary to do corona test on several kinds of conductor bundles. Therefore, a number of experiments were conducted on several kinds of conductor bundles. To reliably analyze ion effects, corona cage test data were obtained over a long period of time under various weather conditions and expressed as a statistical distribution. Ion current density distribution in foul weather shows a significant increase in levels over the corresponding fair weather. Based on this results, we evaluated the environmental characteristic caused by ion flow of three candidated conductor bundles.