• Title, Summary, Keyword: Transfer stability

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Stability Analysis of Anchored Slope Considering Load Transfer (하중전이를 고려한 앵커보강사면의 안정해석)

  • Kim, Nak-Kyung;Yun, Seung-Kwon;Kim, Sung-Kyu;Joo, Yong-Sun;Park, Jong-Sik
    • Proceedings of the Korean Geotechical Society Conference
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    • pp.1113-1124
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    • 2009
  • The limit equilibrium method and finite element method have been commonly used to assess the stability of anchored slope. However, the existing limit equilibrium methods do not consider the load transfer of anchor and, if the potential failure surface crosses the bonded zone of anchors, the anchor loads are not included in computing the factor of safety. In this paper, simplified bishop method, one among several methods based on the limit equilibrium is used to develope the Excel Sheet program and the working load of anchor along the failure surface is calculated by Flamant's formula, proposed by Morlier and Tenier(1982). Additionally, the finite element analysis of anchored slope considering the load transfer is performed in order to compare with the result from the limit equilibrium analysis and analyze the reinforced effect of anchor. From this study, new modelling method that limits the reinforcing range and considers the load transfer is proposed and Excel Sheet program is developed. The factor of safety for several cases between PC STABL and Excel Sheet program is also compared for verification of the program.

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Comparison of Safety factor for an Anchored Slope in Accordance with the Effects of Load Transfer (앵커 하중전이에 따른 사면의 안전율 비교 연구)

  • Kim, Sung-Kyu;Kim, Wak-Kyung;Park, Jong-Sik;Joo, Yong-Sun;Kim, Tae-Hoon
    • Journal of the Korean Geotechnical Society
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    • v.24 no.11
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    • pp.55-60
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    • 2008
  • This paper presents how the load transfer mechanism of the ground anchor affects on the stability analysis of anchored slope. The finite element analysis and the conventional limit equilibrium analysis on the anchored slope were performed and compared. The limit equilibrium analysis of the anchored slope is widely used in design practice due to the easiness of the analysis. However, the load transfer mechanism is not considered properly for the analysis. When the failure surface passes through the bonded length of an anchor, the anchor load is disregarded and the factor of safety for the anchored slope is smaller than it should be. In this study, the load transfer distribution was incorporated into the limit equilibrium stability analysis of the anchored slope and the results were compared with those of finite element analysis.

Dynamic analysis of TRIGA Mark-II reactor (TRIGA Mark-II 원자로의 동특성 해석)

  • 이양수
    • 전기의세계
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    • v.14 no.6
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    • pp.8-13
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    • 1965
  • The TRIGA Mark-II Reactor is very simple to analyze the dynamic characteristics, so that the heat transfer function of the reactor fuel rod is able to be considered as a over-all feedback transfer function. The heat transfer dynamics of the fuel rod is derived under some assumptions. And the over-all reactor transfer function is analytically calcu- lated and it is compared with the measured value. The reactor dynamics and the stability are analyzed by means of the Root-Locus and the Nyquist.

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A Study on the Flame Stability of Porous Ceramic Burner (다공성세라믹버너의 화염안정화에 관한 연구)

  • Lee, Do-Hyung;Yun, Bong-Seok
    • Journal of Power System Engineering
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    • v.20 no.4
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    • pp.12-18
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    • 2016
  • Typical boiler system consists of combustion chamber and heat exchanger in one housing, therefore the size of boiler system is large and the heat exchanging efficiency becomes low. At these boiler systems, because the combustible mixture fires as free flame in the combustion chamber, consequently the combusted hot gas heats the heat exchanger only as conductive and convective heat transfer. The present Porous Ceramic Burner concept is that combustion process is occurred at the gaps of the porous ceramic materials, and the heat exchanger is placed in the same porous materials. Therefore we can reduce the boiler size, and we can also use radiative heat transfer from ceramic material with conductive and convective heat transfer from combusted gas throwing the porous materials. The purpose of this study is to search the flame stability ranges at different fuel flow rate and excess air ratio burning in the $Al_2O_3$ ceramic balls. We found out the stable excess air ratio range on given combustion intensity. And we can get clean porous ceramic combustion results compared with free flame.

Hopf Bifurcation Study of Inductively Coupled Power Transfer Systems Based on SS-type Compensation

  • Xia, Chenyang;Yang, Ying;Peng, Yuxiang;Hu, Aiguo Patrick
    • Journal of Power Electronics
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    • v.19 no.3
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    • pp.655-664
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    • 2019
  • In order to analyze the nonlinear phenomena of the bifurcation and chaos caused by the switching of nonlinear switching devices in inductively coupled power transfer (ICPT) systems, a Jacobian matrix model, based on discrete mapping numerical modeling, is established to judge the system stability of the periodic closed orbit and to study the nonlinear behavior of Hopf bifurcation in a system under full resonance. The general flow of the parameter design, based on the stability principle for ICPT systems, is proposed to avoid the chaos and bifurcation phenomena caused by unreasonable parameter selection. Firstly, based on the state equation of SS-type compensation, a three-dimensional bifurcation diagram with the coupling coefficient as the bifurcation parameter is established with a numerical simulation to observe the nonlinear phenomena in the system. Then Filippov's method based on a Jacobian matrix model is adopted to deduce the boundary of stable operation and to judge the type of the bifurcation in the system. Then the general flow of the parameter design based on the stability principle for ICPT systems is proposed through the above analysis to realize stable operation under the conditions of weak coupling. Finally, an experimental platform is built to confirm the correctness of the numerical simulation and modeling.

The ATC Calculation Method with Thermal Constraints and Voltage Stability Constraints (열적용량과 전압안정도를 고려한 ATC 계산 방법에 관한 연구)

  • Gim, Jae-Hyeon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.21 no.2
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    • pp.86-93
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    • 2007
  • This paper proposes two fast calculation methods of ATC. These two methods evaluate ATC with thermal constraints(Thermal ATC) and ATC with voltage stability constraints(Voltage ATC) respectively. The ATC with thermal constraints was based on the linear incremental power flow to account for the line flow thermal loading effects when the n-1 security constraints were included. The ATC with voltage stability constraints used two-bus equivalents of the system to find the maximum load at a load bus before reaching the voltage stability problem. The methods were tested on the IEEE 30bus systems and the results obtained were compared with those found by some other methods.

The effect of Inclined angle of Channel with multi heat source on Thermal Stability of Electronic Equipment (다수의 열원을 가진 채널의 경사각이 전자장비의 열적 안정성에 미치는 영향)

  • 방창훈;김정수;예용택
    • Journal of the Korean Society of Safety
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    • v.16 no.3
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    • pp.12-18
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    • 2001
  • The objective of the present work is to examine the effect of inclined angle of channel with multi heat source on thermal stability of electronic equipment. The heat sources are mounted on both sides of channel walls by two kinds of configuration such as the zig-zag md symmetric on. Conductive heat transfer was estimated by using of thermocouples and heat flux sensor. Thus, convective heat transfer and mean Nusselt number could be obtained. With increased inclined angle, the convective heat transfer coefficient was decreased. When inclined angle was smaller than 30 degree, The average Nusselt number of Big-zag configuration was larger than that of symmetric. Furthermore, when protruding ration was 0.082, the temperature was strongly affected by inclined angle. whereas, when protruding ration was 0.25, the temperature was strongly affected by heat source configuration.

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A Study on Development of Power Transfer Capability Calculation Algorithm Considering Transient Stability (과도 안정도를 고려한 수송능력 산정 알고리즘의 개발에 관한 연구)

  • Kim, Y.H.;Lee, Buhm;Choi, S.K.;Jo, S.L.;Lee, J.G.;Oh, S.H.;Kim, D.K.
    • Proceedings of the KIEE Conference
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    • pp.95-97
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    • 2003
  • The cost losing synchronous through a transient instability is extremely high in modern power systems. This paper presents a power transfer capability calculation algorithm considering transient stability. The theoretical development is straightforward: dynamic equations are converted to numerically equivalent algebraic equation and then integrated into the standard formulation for power transfer capability calculation.

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A Study on Development of Power Transfer Capability Calculation Algorithm Considering Transient Stability (II) (과도 안정도를 고려한 수송능력 산정 알고리즘의 개발에 관한 연구(II))

  • Kim, Y.H.;Lee, Buhm;Choi, S.K.;Oh, S.H.;Jo, S.L.;Kim, M.Y.
    • Proceedings of the KIEE Conference
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    • pp.128-130
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    • 2004
  • The cost losing synchronous through a transient instability is extremely high in modem power systems. This paper presents a power transfer capability calculation algorithm considering transient stability. The theoretical development is straightforward: dynamic equations are converted to numerically equivalent algebraic equation and then integrated into the standard formulation for power transfer capability calculation. The proposed method is applied to IEEE-24 Reliability Test System and the results shows the effectiveness of the method.

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Optimal Shunt Compensation for Improving Voltage Stability and Transfer Capability in Metropolitan Area of the Korean Power System

  • Choi, YunHyuk;Lee, Byongjun;Kim, TaeKyun
    • Journal of Electrical Engineering and Technology
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    • v.10 no.4
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    • pp.1502-1507
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    • 2015
  • This paper deals with shunt compensation to eliminate voltage violation and enhance transfer capability, which is motivated towards implementation in the Korean power system. The optimal shunt compensation algorithm has demonstrated its effectiveness in terms of voltage accuracy and reducing the number of actions of reactive power compensating devices. The main shunt compensation devices are capacitor and reactor. Effects of control devices are evaluated by cost computations. The control objective at present is to keep the voltage profile of a key bus within constraints with minimum switching cost. A robust control strategy is proposed to make the control feasible and optimal for a set of power-flow cases that may occurs important event from system. Case studies with metropolitan area of the Korean power system are presented to illustrate the method.