• Title/Summary/Keyword: hydraulic power plant

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Modeling & Simulation of a Hydraulic Servo Actuator Cushion for Power Plants (발전소용 유압 서보액추에이터의 쿠션 모델링 및 시뮬레이션)

  • Lee, YongBum;Yoon, Young Hwan
    • Tribology and Lubricants
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    • v.29 no.1
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    • pp.7-12
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    • 2013
  • Turbine power control devices at a nuclear / thermoelectric power plant lead to failure by creating mechanical shocks and strong vibrations that are due to the strong elasticity of a spring and the inertia of the valve face during its rapid movement to block steam. To ensure durability of the turbine power control device, which is the main component in the power plant, it is necessary to develop a device that can prevent such vibrations. In this study, a cushion mechanism is added to the head of the hydraulic servo actuator, which is a turbine power control device. Moreover, the cushion mechanism, which includes various modifies shapes and orifices is investigated dynamically through modeling and simulations.

Study on Evaluation of Internal Leak of Turbine Control Valve in Power Plant Using Acoustic Emission Signal Measurement (음향방출 계측에 의한 터빈 제어밸브 내부누설 평가연구)

  • Lee, S.G.
    • Journal of Power System Engineering
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    • v.12 no.5
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    • pp.65-70
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    • 2008
  • The purpose of this study is to verify availability of the acoustic emission in-situ monitoring method to the internal leak and operating conditions of the turbine major valves relating to safety for turbine operating and prevention of turbine trouble at nuclear power plants. In this study, acoustic emission tests are performed when the pressurized electro-hydraulic control oil flowed through turbine electro-hydraulic controller oil check valve and turbine power/trip fluid solenoid valve in the condition of actual turbine operating. The acoustic emission method was applied to the valves at the site, and the background noise was measured far the abnormal plant condition. To judge for the leak existence ell the object valves, voltage analysis and frequency analysis of acoustic signal emitted from infernal leak in the valve operating condition are performed. It was conformed that acoustic emission method could monitor for valve internal leak to high sensitivity.

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Force Control of one pair of 6-Link Electro-Hydraulic Manipulators (한 쌍의 6축 전기유압 매니퓰레이터의 힘제어)

  • 안경관;조용래;양순용;이병룡
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 1997.10a
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    • pp.353-356
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    • 1997
  • Hydraulically driven manipulators are superior to electrically driven ones in the power density and electrical insulation. But an electro-hydraulic manipulator using hydraulic actuators has many nonlinear elements, and this parameter fluctuations are greater than those of electrically driven manipulator. So this is relatively difficult to realize not only stable contact work but also accurate force control for the autonomous field task such as the maintenance task of high voltage active electric line or the automatic excavation task by hydraulic excavator. In this report, we propose robust force control algorithm, which can be applied to there real field task such as the construction field, nuclear plant and so on. Proposed force controller has the same structure as that of disturbance observe for position control. The difference between force and position disturbance observer is that the input and output of disturbance observer are forces in the case force disturbance observer and the plant varies much compared to the case of position control. In the design of force disturbance observer, generalized plant is derived and the stabilized filter is designed by H infinity control theory to ensure the robuts t stability even though the stiffness of environment changes from sponge to steel, and the contact surface also changes from flat to round shape. Experimental results show that highly robust force tracking by a 6-link electro-hydraulic manipulator could be achieved under various environment conditions.

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Comparison of Control Performance in Electro.hydraulic Servo Systems (전기.유압 서보 시스템의 제어성능 비교)

  • Kim, D.T.;Park, K.S.
    • Transactions of The Korea Fluid Power Systems Society
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    • v.3 no.2
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    • pp.14-20
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    • 2006
  • A controller design procedure for an electro-hydraulic positioning systems has been developed using $H{\infty}$ control. The generalized plant models and weighting function for multiplicative uncertainty modelling error was presented along with $H{\infty}$ controller designs in order to investigate the robust stability and performance. Both disturbance rejection and command tracking performances were improved with the $H{\infty}$ controller, and the better uniformity of time response is achieved across wide range of operating conditions than the PID, LQR and LQG control scheme. The multiplicative uncertainty case was specifically suited for the design of an electro-hydraulic positioning control systems using $H{\infty}$ control.

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Thermal Hydraulic Analysis Methodology for PWR Nuclear Power Plant Steam Generators (원전 가압경수로 증기발생기 열유동 해석법)

  • Choi, Seok-Ki;Nam, Ho-Yun;Kim, Eui-Kwang;Kim, Hyung-Nam;Jang, Ki-Sang;Hong, Sung-Yull
    • Proceedings of the KSME Conference
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    • 2001.06e
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    • pp.463-468
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    • 2001
  • This paper presents the methodology for thermal hydraulic analysis of Pressurized Water Reactor (PWR) steam generators. Topics include porous media approach, governing equations, physical models and correlations for solid-to-fluid interaction and heat transfer and numerical solution scheme. Some details about the ATHOS3 code currently used widely for thermal hydraulic analysis of PWR steam generators in the industry are presented. The ATHOS3 code is applied to the thermal hydraulic analysis of steam generator in the Korea YGN 3&4 nuclear power plant and the computed results are presented.

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On the Analysis of Dynamic Characteristics of Pipe Supporting Hydraulic Snubber in Electric Power Plant with State-space Model and Impulse Testing (상태공간 모델과 임펄스 시험에 의한 발전소 배관지지용 유압완충기의 동특성 해석)

  • Lee, Jae-Cheon;Im, Mun-Hyeok;Hwang, Tae-Yeong
    • Journal of the Korean Society for Precision Engineering
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    • v.19 no.10
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    • pp.130-138
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    • 2002
  • This paper presents the modeling and analysis of dynamic characteristics of hydraulic snubber in electric power plant. The nonlinear state-space model of 14th order to describe the dynamics of the snubber was established by Simulink. The simulation results show that the hydraulic snubber reacts as like the conventional shock absorbers against the high pulse shock load. The snubber also shows the peculiar characteristics to the small step load, which temporarily lock the control valves up, however maintain same steady-state pressures of all internal chambers in the long run. Two case studies for the analysis of the snubber were addressed. Practical pulse testing method was also proposed to identify the frequency response characteristics of the snubber.

Proper Conditions of Structure to Prevent Eddy Creation in Cooling Water Intake Canal of Stream Power Plant (화력발전소 냉각 취수로내의 와류발생 방지를 위한 구조물의 적정조건검토)

  • 조진훈;천만복
    • Proceedings of the Korean Society of Agricultural Engineers Conference
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    • 1999.10c
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    • pp.465-472
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    • 1999
  • Hydraulic model tests are performed to find economical and hdrqulically stable design of cooling water intake channel of steam power plant. The result of tests show that the standard distributiion of y-components in the chamber of CWP(circulating Water Pump) are recommended below 3.5 to maintain hydraulic stability, so that this value is considered as the design criteria. Common basin is necessary to improve the hydraulic stability of inflow, however the longer basin does not always improve the hydraulic stability , and the optimal length of basin can be found in some range. From the results the flow stability maintained the best condition when the length of basin is 7.2m. Beside the standard tests the auxiliary tests like edge , baffle, trapezoidal section and increase of pump capacity are carried out based on the optimal condition foudn in the standard tests. From the series of tests the economical and hydraulically stable design of intake channel was proposed.

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On the Analysis of Dynamic Characteristics of Pipe Supporting Hydraulic Snubber in Electric Power Plant with State-space Model and Impulse Testing (상태공간 모델과 임펄스 시험에 의한 발전소 배관지지용 유압완충기의 동특성 해석)

  • Lee, Jae-Cheon;Hwang, Tae-Yeong
    • 연구논문집
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    • s.31
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    • pp.89-99
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    • 2001
  • This paper presents the modeling and analysis of dynamic characteristics of hydraulic snubber in electric power plant. The nonlinear state-space model of 14th order to describe the dynamics of the snubber was established by Simulink. The simulation results show that the hydraulic snubber reacts as like the conventional shock absolvers against the high pulse shock load. The snubber also shows the peculiar characteristics to the small step load, which temporarily lock the control valves up, however maintain same steady-state pressures of all internal chambers in the long run. Two case studies for the analysis of the snubber are addressed. Practical pulse testing method was also proposed to identify the frequency response of the snubber.

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Static Characteristics of Electro-Hydraulic Spring Return Actuator (전기유압식 스프링복귀 액추에이터 정특성)

  • Jung, G.H.
    • Journal of Drive and Control
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    • v.9 no.2
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    • pp.8-14
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    • 2012
  • Electro-hydraulic spring return actuator(ESRA) is utilized for air conditioning facilities in a nuclear power plant. It features self-contained, hydraulic power that is integrally coupled to a single acting hydraulic cylinder and provides efficient and precise linear control of valves as well as return of the actuator to the de-energized position upon loss of power. In this paper, the algebraic equations of ESRA at steady-state have been developed for the analysis of static characteristics that includes control pressure and valve displacement of pressure reducing valve, flow force on flapper as well as its displacement over the entire operating range. Also, the effect of external load on piston deviation is investigated in terms of linear system analysis. The results of static characteristics show the unique feature of force balance mechanism and can be applied to the stable self-controlled mechanical system design of ESAR.

Design of a Partial Inter-tube Lancing System actuated by hydraulic power for type F model Steam Generator in Nuclear Power Plant (수압구동 전열관다발 부분 삽입형 증기발생기 세정장비 설계)

  • Kim, S.T.;Jeong, T.W.
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1132-1135
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    • 2008
  • The sludge grown up in steam generators of nuclear power plants shortens the life-cycle of steam generators and reduces the output of power plants. So KHNP(Korea Hydro and Nuclear Power), the only nuclear power utility in Korea, removes it periodically using a steam generator lancing system during the outage of plants for an overhaul. KEPRI(Korea Electric Power Research Institute) has developed lancing systems with high pressured water nozzle for steam generators of nuclear power plants since 2001. In this paper, the design of a partial inter-tube lancing system for model F type steam generators will be described. The system is actuated without a DC motor inner steam generators because the motors in a steam generator make a trouble from high intensity of radioactivity as a break down.

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