• Title/Summary/Keyword: Power Qualify

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A Basic Study on the Development of the Single-Phase Unified Poorer Quality Conditioner (단상용 통합형 전력품질 개선장치의 개발에 관한 기초연구)

  • 노대석;이현옥;오성철;최재석;차준민;김재언
    • The Transactions of the Korean Institute of Electrical Engineers A
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    • v.52 no.2
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    • pp.90-98
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    • 2003
  • Recently, the increasing application of electronic equipments and information devices has heightened the interest in power qualify. The term power quality is applied to a wide range of electromagnetic phenomena on the power system and is also concentrated by all areas such as utilities, their customers and suppliers of load equipments. In engineering terms, power Qualify is expressed by voltage qualify because the power supply system can only control the quality of the voltage. Therefore, the standards in power quality area are devoted to keep the supply voltage within allowable limits. This paper deals with single-phase unified power quality conditioner (UPQC), which ai s at the integration of series-active and shunt-active filter. The series filter il used to compensate for the voltage distortions and the shunt filter is used to provide reactive power and counteract the harmonic current injected by the load. Also, the voltage of the DC link capacitor is controlled to a desired value by the shunt active filter. The validity of the proposed UPQC is demonstrated using both the MATLAB/SIMULINK simulation and the experimental device with DSP (TMS320C32).

The Design of control algorithm for 150kVA power quality compensator (150kVA급 전기품질 보상기기 제어 알고리즘 설계)

  • Jeon, Jin-Hong;Kim, Ji-Won;Chun, Yeung-Han;Kim, Ho-Young
    • Proceedings of the KIEE Conference
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    • 2001.07b
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    • pp.1070-1072
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    • 2001
  • In recent years, customers and power supplies are interested in power quality. Demands of customers are change from standard quality of distribution power system to various high quality of distribution power system. so, it is necessary to apply power quality compensator, in our project, we develop the power quality compensator of 150kVA which compensates power factor and voltage sag, interruption. it is very frequently occurred power qualify problems[1,2]. As a series and shunt compensator, power quality compensator consists of two inverters with common do link capacitor bank. It compensates the current quality in the shunt part and the voltage qualify in the series part. In this paper we present the design and control algorithm of power quality compensator. As a control algorithm is implemented by digital controller, we consider sample-and-hold of signals. In this simulation, we use EMTDC/PSCAD V3.0 software which can simulate instantaneous voltage and current.

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Cutting Power Based Feedrate Optimization for High-Efficient Machining (고능률 가공을 위한 절삭 동력 기반의 이송 속도 최적화)

  • Cho Jaewan;Kim Seokil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.2 s.233
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    • pp.333-340
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    • 2005
  • Feedrate is one of the factors that have the significant effects on the productivity, qualify and tool life in the cutting mechanism as well as cutting velocity, depth of cut and width of cut. In this study, in order to realize the high-efficient machining, a new feedrate optimization method is proposed based on the concept that the optimum feedrate can be derived from the allowable cutting power since the cutting power can be predicted from the cutting parameters as feedrate, depth of cut, width of cut, chip thickness, engagement angle, rake angle, specific cutting force and so on. Tool paths are extracted from the original NC program via the reverse post-processing process and converted into the infinitesimal tool paths via the interpolation process. And the novel NC program is reconstructed by optimizing the feedrate of infinitesimal tool paths. Especially, the fast feedrate optimization is realized by using the Boolean operation based on the Goldfeather CSG rendering algorithm, and the simulation results reveal the availability of the proposed optimization method dramatically reducing the cutting time and/or the optimization time. As a result, the proposed optimization method will go far toward improving the productivity and qualify.

STATCOM System Simulation Used by the PSIM Software (PSIM 소프트웨어에 의한 STATCOM 시스템 시뮬레이션)

  • Lee, Hwa-Su;Kim, Yong-Heon;Lee, Eun-Woong;Lee, Dong-Ju
    • Proceedings of the KIEE Conference
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    • 2003.04a
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    • pp.94-96
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    • 2003
  • The study for improvement of power qualify is widely performed, because most equipments used semi-conductor are very sensitive for power quality. In this paper, we performed modeling for STATCOM system which developed using SCRs, and suggested the compensation principle of reactive Power by simulations used PSIM software. We will apply this results to 30kVA STATCOM under manufacturing.

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Stencil cutting process by Nd:YAG laser II -Influence of process parameters on cutting characteristics of stencil- (Nd:YAG레이저를 이용한 스텐실 절단공정II -레이저의 공정변수가 스텐실 절단특성에 미치는 영향-)

  • Lee, Je-Hoon;Seo, Jung;Kim, Jung-Oh;Shin, Dong-Sik;Lee, Young-Moon
    • Laser Solutions
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    • v.4 no.2
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    • pp.47-57
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    • 2001
  • This study deals with the laser cutting of stencil for the PCB. The most important aim of this study is to determine optimal conditions which make good-qualify stencil in Nd:YAG laser cutting. We made an experiment according to various variables (power. type of mask. gas pressure, cutting speed, and pulse width) and analyzed the cutting characteristics (surface roughness, kerf width. dross) . Each variable has optimal value for good-qualify cut edge under fixed condition. And neural network after learning experimental data with a million time iteration could predict surface roughness of cut edge under arbitrary condition approximately.

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Data Compression using Waveform Comparison (파형 비교를 이용한 데이터 압축 기법)

  • Sung, S.M.;Lim, S.I.;Lee, S.J.;Bae, Y.J.;Jin, Y.W.;Kim, J.H.;Kim, B.J.
    • Proceedings of the KIEE Conference
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    • 2003.07a
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    • pp.151-153
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    • 2003
  • This paper was studied on using data of the protective relay by Power Quality Monitor. The protective relay will have problem to save data for PQM(Power Qualify Monitoring) analysis because the protective relay memory is limited. So this paper was proposed new data compression of the data was get from the protective relay. The scheme is compared each cycle after DFT(Discrete Fourier Transform). And scheme is verified through simulation of protective relay data was from real distribution system.

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A Study on Filcker Evaluation Considering Power Quality Disturbance of Power System (전력계통의 전력품질 외란을 고려한 플리커 평가에 관한 연구)

  • Jung, Seung-Bock;Kim, Jae-Chul
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • 2006.05a
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    • pp.376-379
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    • 2006
  • This paper studies flicker evaluation considering power quality disturbance. A flicker problem with light device irritates human's eyes. Also, the flicker problem has an influence on adverse effect such as rolling device and rotating device. However, a study of flicker evaluation is not complete. A flicker is measured and evaluated at monitoring point. But we consider power qualify disturbances such as voltage sag and transient that cause fault and inverter/breaker switching. Power quality disturbances affects flicker evaluation. A flicker evaluation index increases. Therefore, we consider power quality disturbances. We detect voltage sag and transient using wavelet and evaluate flicker without flicker index including power quality disturbances.

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QUALIFICATION, CONDITION MONITORING, AND MANAGEMENT OF AGEING OF LOW VOLTAGE CABLES IN NUCLEAR POWER PLANT (Global Today - 원자력발전소 저전압 케이블의 노화에 대한 적격, 상태 모니터링 및 관리 (1))

  • Kang, Ki Sig
    • JOURNAL OF ELECTRICAL WORLD
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    • s.451
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    • pp.46-58
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    • 2014
  • At the end of 2013, there were 434 nuclear power reactors in operation worldwide, with a total capacity of 371.6 GW(e), approximately 80 % had been in service 20 years and more. Many Member States have given high priority to licensing their nuclear power plants to operate for terms longer than the time frame originally anticipated(e.g. 30 or 40 years). One of challenges for long term operation is cable ageing management. How can qualify the existing cable under harsh environment in nuclear power plant? The paper described the approaches on qualification, condition monitoring, and management of low voltage cables in nuclear power plant.

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