• 대한전기학회논문지:전력기술부문A
• /
• 제48권5호
• /
• pp.517-523
• /
• 1999

The Start-up transformers or on-site stand-by transformers are installed for the start-up and shut-down of generator and emergency status in unclear power plant. The on-site power supply configuration using these transformers must be detemined by considering configuration requirements, site characteristics, reliability and availability severely because it is remarkably important for safety and benefit of plant. The start-up or stand-by power supply configuration has been determined considering only safety requirements and construction cost up to now in Korea. I study various reliability estimating methods for the prediction of availability, and estimate the unavailability for the start-up power supply system of two 1,000㎿ unclear power plants. I also detemine the reliability and unavailability and unavailavility of equipment, system and configuration using FTA method.

• 드라이브 ㆍ 컨트롤
• /
• 제21권2호
• /
• pp.44-52
• /
• 2024

In this study, we predicted PTO power requirements based on torque predicted by the discrete element method and the multi-body dynamics coupling method. Six different scenarios were simulated to predict PTO power requirements in different soil conditions. The first scenario was a tillage operation on cohesionless soil, and the field was modeled using the Hertz-Mindlin contact model. In the second through sixth scenarios, tillage operations were performed on viscous soils, and the field was represented by the Hertz-Mindlin + JKR model for cohesion. To check the influence of surface energy, a parameter to reproduce cohesion, on the power requirement, a simple regression analysis was performed. The significance and appropriateness of the regression model were checked and found to be acceptable. The study findings are expected to be used in design optimization studies of agricultural machinery by predicting power requirements using the discrete element method and the multi-body dynamics coupling method and analyzing the effect of soil cohesion on the power requirement.

• Journal of Power Electronics
• /
• 제6권2호
• /
• pp.104-113
• /
• 2006

Satellites have provided the impetus for the orderly development of reliability engineering research and analysis because they tend to have complex systems and hence acute problems. They were instrumental in developing mathematical models for reliability, as well as design techniques to permit quantitative specification, prediction and measurement of reliability. Reliability engineering is based on implementing measures which insure an item will perform its mission successfully. The discipline of reliability engineering consists of two fundamental aspects; $(1^{st})$ paying attention to details, and $(2^{nd})$ handling uncertainties. This paper uses some of the basic concepts, formulas and examples of reliability theory in application. This paper emphasizes the practical reliability analysis of a Low Earth Orbit (LEO) Micro-satellite power subsystem. Approaches for specifying and allocating the reliability of each element of the power system so as to meet the overall power system reliability requirements, as well as to give detailed modeling and predicting of equipment/system reliability are introduced. The results are handled and analyzed to form the final reliability results for the satellite power system. The results show that the Electric Power Subsystem (EPS) reliability meets the requirements with quad microcontrollers (MC), two boards working as main and cold redundant while each board contains two MCs in a hot redundant.

• 수산해양기술연구
• /
• 제39권4호
• /
• pp.298-304
• /
• 2003

In this paper a free-form hull design program and performance prediction program for planing boat is introduced. This program enables the designer to do complex geometric hull shape design on a personal computer and accurately to predict power requirements for a given loading and velocity. For a free form design, Bezier curve model is adopted as a basic representation tool of curves and surfaces, and this program has versatile functions to do fairing jobs with a convenient graphical user interface. After creating a hull form the geometric data is provided in a manner compatible with a variety of analysis tools including 'Motion Analysis(by Zarnick)' for prediction of motion characteristics in regular waves, 'Running Attitude (by Savitsky)' for prediction of the running attitude and required power.

• 소음진동
• /
• 제9권6호
• /
• pp.1116-1122
• /
• 1999

HRSG, which is one of main components of the combined cycle power plant,is composed of an inlet duct, a main body and casing, an outlet duct and a stack. It is important to design HRSG wihtin the allowable noise limit. For this purpose, it is necessary to analyze and predict the noise reduction and radiation at HRSG. In this paper, the technology for the noise prediction at each part of HRSG has been based on the empirical and field data, and also the HRSG noise prediction program has been developed. In order to verify the developed technology and program a field test is conducted. The results of noise prediction show good agreement with the measured.

• Journal of Biosystems Engineering
• /
• 제16권2호
• /
• pp.142-147
• /
• 1991

곡물을 수확하는데 필요로하는 동력의 상당부분이 탈곡부 급동에서 소요된다. 예취된 작물 전부가 탈곡부에 투입되는 콤바인의 경우 급동 소요동력이 전체 소요동력의 80%까지 되기도 하며, 축류식의 경우가 보통형인 경우보다 높은 급동 소요동력을 보인다. 수확된 곡물의 가치가 작업기의 동력비 및 운영비 보다 커야하므로, 급동 소요동력모델은 경제성을 고려한 콤바인의 설계 및 작동을 유도해 내는데 기본이 된다. 본 논문에서는 콤바인 급동의 소요동력을 예측하기 위해 탈곡현상에 기초를 둔 수학적 모델을 개발하였다. 급동에 부착된 라습바(rasp-bak)의 수, 수망과 급동의 간격, 수망의 길이, 공급물의 두께, 공급율, 급동회전속도 둥의 변수들을 포함한 수식이 개발되었으며 급동의 크기에 의한 영향도 고려되었다. 개발된 모델은 측정된 자료와 잘 일치했으며 ($R^2$=0.9) 높은 신뢰도를 보였다.

• 한국철도학회:학술대회논문집
• /
• 한국철도학회 2009년도 춘계학술대회 논문집
• /
• pp.1473-1479
• /
• 2009

Recently, the high speed train was operated and then the train system's reliability requirements are growing more and more. The exact prediction simulation is necessary in the design of power feeding system by the increase of railway electrification. In order to develope the AC feeding system analysis technology, real-time power simulator was manufactured. It is composed to eight channels analog input, forty channels analog output and forty-eight channels digital I/O. The size of simulator rack is 19" and the two I/O boards are installed the PXI chassis built into the real time os. The signal I/O is possible through BNC connector. The test results of manufactured simulator are obtained that the error range of analog I/O signal is below 1 % and simulation condition is set to 1 ms and the simulation output of the analog output compares the results of the simulator.

• 조명전기설비학회논문지
• /
• 제29권7호
• /
• pp.28-37
• /
• 2015

Owing to the variability of large-scaled wind power system, the development of wind farm management technologies and related compensation methods have been receiving attention. To provide an accurate and reliable output power, certain wind farm adopts a specified management system including a wind prediction model and grid expectation solutions for considering grid condition. Those technologies are focused on improving the reliability and stability issues of wind farms, which can affect not only nearby system devices but also a voltage condition of utility grid. Therefore, to adapt the develop management system, an expectation process about voltage condition of Point of Common Coupling should be integrated in operating system for responding system requirements in real-time basis. This paper introduce a grid imposing method for a real-time based wind farm management system. The expected power can be transferred to the power flow section and the required quantity about reactive power can be calculated through the proposed system. For the verification process, the gauss-seidel method is introduced in the Matlab/Simulink for analysing power flow condition. The entire simulation process was designed to interwork with PSCAD for verifying real power system condition.

• Nuclear Engineering and Technology
• /
• 제35권5호
• /
• pp.399-411
• /
• 2003

A model predictive control method is applied to design an automatic controller for thermal power control in a reactor core. The basic concept of the model predictive control is to solve an optimization problem for a finite future at current time and to implement as the current control input only the first optimal control input among the solutions of the finite time steps. At the next time step, the second optimal control input is not implemented and the procedure to solve the optimization problem is then repeated. The objectives of the proposed model predictive controller are to minimize the difference between the output and the desired output and the variation of the control rod position. The nonlinear PWR plant model (a nonlinear point kinetics equation with six delayed neutron groups and the lumped thermal-hydraulic balance equations) is used to verify the proposed controller of reactor power. And a controller design model used for designing the model predictive controller is obtained by applying a parameter estimation algorithm at an initial stage. From results of numerical simulation to check the controllability of the proposed controller at the $5\%/min$ ramp increase or decrease of a desired load and its $10\%$ step increase or decrease which are design requirements, the performances of this controller are proved to be excellent.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 2011년도 제42회 하계학술대회
• /
• pp.868-869
• /
• 2011

Domestic Foreign automaker's are focused on the high-efficiency, low emission cars development. On the way, the hybrid car is the first priority. Hybrid electric vehicle battery pack configurations, EV Relay one of the key components of the engine driving, to assist in the drive motor to supply electrical energy to the battery is a device for opening and closing of the output device. EV Relay determine the longevity and the replacement cycle, The EV Relay environmental conditions and duty cycle considering the reliability tests are essential requirements of many automotive companies to respond to RFQ, this test is essential. This paper using Maxwell Software for Prediction of the Ev Relay impulse, the theoretical data to obtain the impulse to develop methods for mechanical testing after to take advantage of it.