• Title/Summary/Keyword: power system equivalent

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TRV analysis by using multi - port equivalent (다 단자망 축약 이론을 이용한 TRV 해석)

  • Yoon, Jae-Young;Moon, Young-Hyun;Park, Dong-Wook
    • Proceedings of the KIEE Conference
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    • 1988.11a
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    • pp.236-240
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    • 1988
  • The simplified equivalent by using the short circuit impedance has been used for analyzing the prospective transient recovery voltage of the large power system. But it sometimes generates untorelable error in the rate-of-rise of TRV when using the Thevenin equivalent source. This paper provides the new equivalent by using the multi-port theory. The application of the new method to the sample system gives satisfactory accuracy compared with the short-circuit equivalent.

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Soft-switching Current Source inverter for Power System Interconnection (소프트 스위칭 전류원 인버터를 이용한 계통연계형 전력변환기)

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    • Proceedings of the KIPE Conference
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    • 2000.07a
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    • pp.392-395
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    • 2000
  • This paper proposes a soft-switching current -source inverter with a sitched-capacitor module The system operation was analyzed by a theoretical approach with equivalent circuits and verified by a computer simulation with ISPICE software. The proposed system could be effectively applied for the power converter of photovoltaic power generation interconnected with the power system.

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Probabilistic Reliability Based Grid Expansion Planning of Power System Including Wind Turbine Generators

  • Cho, Kyeong-Hee;Park, Jeong-Je;Choi, Jae-Seok
    • Journal of Electrical Engineering and Technology
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    • v.7 no.5
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    • pp.698-704
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    • 2012
  • This paper proposes a new methodology for evaluating the probabilistic reliability based grid expansion planning of composite power system including the Wind Turbine Generators. The proposed model includes capacity limitations and uncertainties of the generators and transmission lines. It proposes to handle the uncertainties of system elements (generators, lines, transformers and wind resources of WTG, etc.) by a Composite power system Equivalent Load Duration Curve (CMELDC)-based model considering wind turbine generators (WTG). The model is derived from a nodal equivalent load duration curve based on an effective nodal load model including WTGs. Several scenarios are used to choose the optimal solution among various scenarios featuring new candidate lines. The characteristics and effectiveness of this simulation model are illustrated by case study using Jeju power system in South Korea.

A Development of Ethernet-Based Remote Diagnosis System for DC Voltage Smoothing Capacitor using DSP (DSP를 적용한 전력용 DC 평활 커패시터의 이더넷 원격 고장진단시스템 개발)

  • Shon, Jin-Geun
    • The Transactions of the Korean Institute of Electrical Engineers P
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    • v.60 no.2
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    • pp.94-98
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    • 2011
  • Electrolytic power capacitors today form essential components for virtually any power electronic system such as DC/DC converter or UPS. Frequently, electrolytic capacitors for DC link voltage smoothing are the key components which determine the life cycle of the whole unit and often are responsible for converter breakdown failures. In this paper, ethernet-based remote diagnosis system for DC voltage smoothing capacitor using DSP control board is developed. To estimate the status of the capacitor, the equivalent series resistor(ESR) of the component has to be determined. The ESR detection scheme is based on the determination of the capacitor ripple power losses calculated from DC link voltage/current measurement. Experimental results show the veridity and reliability of the proposed ethernet-based remote on-line capacitor diagnosis system.

A Study on the Fuel Cell Equivalent Circuit Modeling (연료전지 수치해석을 이용한 등가회로 모델링 연구)

  • OH, HWANYEONG;CHOI, YOON YOUNG;SOHN, YOUNG-JUN
    • Transactions of the Korean hydrogen and new energy society
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    • v.33 no.3
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    • pp.226-231
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    • 2022
  • Power converter are usually equipped for fuel cell power generation system to connect alternating current (AC) electric power grid. When converting direct current (DC) of fuel cell power source into AC, the power converter has a frequency ripple, which affects the fuel cell and the grid. Therefore, an equivalent circuit having dynamic characteristics of fuel cell power, for example, impedance, is useful for designing an inverter circuit. In this study, the current, voltage and impedance characteristics were calculated through fuel cell modeling and validated by comparing them with experiments. The equivalent circuit element values according to the current density were formulated into equations so that it could be applied to the circuit design. It is expected that the process of the equivalent circuit modeling will be applied to the actual inverter circuit design and simulated fuel cell power sources.

A Study on the Equivalent Model of an External Electrode Fluorescent Lamp Based on Equivalent Resistance and Capacitance Variation

  • Cho, Kyu-Min;Oh, Won-Sik;Moon, Gun-Woo;Park, Mun-Soo;Lee, Sang-Gil
    • Journal of Power Electronics
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    • v.7 no.1
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    • pp.38-43
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    • 2007
  • An External Electrode Fluorescent Lamp (EEFL) has longer lifespan, higher power efficiency and higher luminance than a Cold Cathode Fluorescent Lamp (CCFL). Moreover, it is easy to drive them in parallel. Therefore, the EEFL is expected to quickly replace the CCFL in LCD backlight systems. However, the EEFL has more complex characteristics than the CCFL with a resistive component, because it has both a resistive component by plasma and a capacitive component by external electrode. In this paper, values of resistance and capacitance are measured at several power levels and at several operating frequencies. They are expressed by a numeral formula based on a linear approximation that represents the equivalent resistance and capacitance as a function of power. Then we made block diagram of the equivalent circuit model using numerical expressions. Simulation waveforms and experimental results are presented to verify the feasibility of the equivalent model.

A Phase-Domain Equivalent Representation for Electromagnetic Transients Studies (전력계통 과도현상 해석을 위한 상영역에서의 등가축약 기법)

  • Jung, B.T.;Kim, S.H.;Heo, S.I.;Ahn, B.S.;Hong, J.H.
    • Proceedings of the KIEE Conference
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    • 1996.07b
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    • pp.731-733
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    • 1996
  • In this paper, a new time-domain reduction method for unbalanced 3 phase power systems will be represented. The impulse response of the system is used to identify a discrete-time equivalent filter model. The model is formulated directly in the phase domain. Each phase has a self-mode equivalent model and two mutual-mode equivalent models. The equivalent model is determined by the transfer function identification technique based on the Prony analysis. The model is implemented in EMTDC and tested with an unbalanced 3 phase network. The result of test showed that the equivalent model is accurate.

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Contingency Selection For EMS Operation (EMS 운용을 위한 상정사고 선정)

  • Kim, Jung-Nyun;Baek, Young-Sik
    • Proceedings of the KIEE Conference
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    • 1996.11a
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    • pp.175-178
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    • 1996
  • Power system is becomming more and more complex and large. So system is stressed increasingly. This paper presents a method to select contingency ranking in power systems for EMS operation. Firstly, the proposed method is applied line outage using Thevenin equivalent circuit. Secondly, Contingency harmful to system is selected by loss variation between base case and fault. Thirdly, this paper prescribed simulated line sequence. Therefore this algorithm shows higher computation speed and effective memory use.

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Development of on-line Transient Security Assessment Algorithm (온라인 과도안전도 평가 알고리즘 개발)

  • Kim Y. H.;Cha S. T.;Kim T. K.;Kim H. K.;Jeon M. R.;Choo J. B;Nam H. K.
    • Proceedings of the KIEE Conference
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    • summer
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    • pp.91-93
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    • 2004
  • This paper is to develope the fast screening algorithm for on line transient security assessment. All generators are represented in a classical model and stability index is defined as a ratio between acceleration power and deceleration power Critical machines and remaining machines are identified based on stability index and aggregated into two equivalent machines. And finally equivalent machines are reduced into OMIB system then CCT is computed. The Proposed algorithm is applied to the KEPCO system and obtained the reasonable results compared with TSA Tool.

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Bending Analysis and Flexural Rigidity of Rectangular Corrugated Plates (사각 주름판의 굽힘강성 및 굽힘해석)

  • Jung, Kang;Kim, Young-Wann
    • Journal of Power System Engineering
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    • v.16 no.6
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    • pp.38-44
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    • 2012
  • In this paper, the bending characteristics of the corrugated plates is analyzed. The trapezoidally, triangularlly and sinusoidally corrugated plates are considered. The corrugated plate is treated as an orthotropic plate that has different flexural properties in two perpendicular directions. The equivalent bending and twisting rigidities for the equivalent orthotropic plates are derived. The equivalent flexural rigidities are estimated under the following postulations: (1) The angle of continuously corrugated plate is not changed after the deformation. (2) When the pure bending moment is applied in corrugated direction of the plate, the its plane is in pure bending. Several numerical examples are analyzed with the proposed method and compared with published results.