• Title/Summary/Keyword: Working Power

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A Study on the Monitoring System of Passive Filter to Improve Power Quality (전력품질 개선을 위한 수동필터 모니터 시스템에 관한 연구)

  • Yu, Jae-Geun;Lee, Sang-Ik;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 2007.07a
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    • pp.89-91
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    • 2007
  • In this paper, we developed DSP based control system to automatically open and close passive filter, which is used to reduce harmonics, according to operating condition of loads. Passive filter control system automatically open and close each branch of filter according to working conditions of loads by sending signals to open and close installation of passive filter after measuring and monitoring voltage, current, harmonics, reactive power, power factor and so on. We verified it's performance by connecting control system with passive filter in the power line using the 100[HP] d.c. motor drive, opening and closing passive filter according to operation condition of motor, and measuring harmonics and reactive power, etc.

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Physical Modeling of SiC Power Diodes with Empirical Approximation

  • Hernandez, Leobardo;Claudio, Abraham;Rodriguez, Marco A.;Ponce, Mario;Tapia, Alejandro
    • Journal of Power Electronics
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    • v.11 no.3
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    • pp.381-388
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    • 2011
  • This article presents the development of a model for SiC power diodes based on the physics of the semiconductor. The model is able to simulate the behavior of the dynamics of the charges in the N- region based on the stored charge inside the SiC power diode, depending on the working regime of the device (turn-on, on-state, and turn-off). The optimal individual calculation of the ambipolar diffusion length for every phase of commutation allows for solving the ambipolar diffusion equation (ADE) using a very simple approach. By means of this methodology development a set of differential equations that models the main physical phenomena associated with the semiconductor power device are obtained. The model is developed in Pspice with acceptable simulation times and without convergence problems during its implementation.

A Study on Power Quality Diagnosis System using Neural NetWorks (전기품질 진단 시스템 개발을 위한 인공 신경망 적용에 관한 연구)

  • Kim, Jin-Su;Kim, Young-Il;Kim, Kwang-Soon;Park, Gi-Ju
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.56 no.8
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    • pp.1351-1359
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    • 2007
  • In this paper, we have studied the power quality(PQ) diagnosis system with the two methods for PQ diagnosis. One to Apply a regulation value in compliance with mathematics calculation, and the other Automatic identification using Neural network algorithm. Neural network algorithm is used for an automatic diagnosis of the PQ. The regulation proposed by IEEE 1159 Working group is applied for the precision of the diagnosis. In order to divide accurate segmentation, the algorithm for a computer training used the back propagation out of several neural network algorithms. We have configured the proto-type sample by using Labview and a programmed Neural Networks Algorithm using with C. And arbitrary electric Signal generated by OMICRON Company's CMC 256-6 for an efficiency test.

A Study for the Restoration of Hong Dae-Yong Honsangui - Focusing on the structure and operating mechanism -

  • Lee, Yong Sam;Kim, Sang Hyuk;Park, Je Hoon
    • Journal of Astronomy and Space Sciences
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    • v.30 no.3
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    • pp.187-192
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    • 2013
  • Honsangui (celestial globe) which is a water-hammering method astronomical clock is recorded in "Juhaesuyong" which is Volume VI of supplement from "Damheonseo", written by Hong Dae-Yong (1731~1783). We made out the conceptual design of Hong Dae-Yong's Honsangui through the study on its structure and working mechanism. Honsangui consist of three rings and two layers, the structure of rings which correspond to outer layer is similar to his own Tongcheonui (armillary sphere) which is a kind of armillary sphere. Honsang sphere which correspond to inner layer depicts constellations and milky way and two beads hang on it as Sun and Moon respectively for realize the celestial motion. Tongcheonui is operated by the pendulum power but Honsangui is operated by water-hammering method mechanism. This Honsangui's working mechanism is the traditional way of Joseon and it was simplified the working mechanism of Shui y$\ddot{u}$n i hsiang t'ai which is a representative astronomical clock of China. This record of Honsangui is the only historical record about the water-hammering method working mechanism of Joseon Era and it provide the study of water-hammering method mechanism with a vital clue.

Basic Static Characteristics of a Closed and a Regeneration Cycles for the OTEC System (해양온도차발전 Closed and Regeneration Cycle의 기본 정특성)

  • Cha, Sang-Won;Kim, You-Taek;Mo, Jang-Oh;Lim, Tae-Woo;Lee, Young-Ho
    • Journal of Advanced Marine Engineering and Technology
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    • v.36 no.8
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    • pp.1151-1157
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    • 2012
  • Ocean Thermal Energy Conversion(OTEC) technology is one of the new and renewable energy that utilizes the natural temperature gradient that exists in the tropical ocean between warm surface water and the deep cold water, to generate electricity. The selection of working fluid and the OTEC cycle greatly influence the effect on the system operation, and it's energy efficiency and impacts on the environment. Working fluids of the OTEC are ammonia, R22, R407C, and R410A. In this paper, we compared boiling pressure to optimize OTEC system at $25^{\circ}C$. Also, this paper showed net-power and efficiency according to working fluids for closed cycle and regeneration cycle.

Study of Working Fluids on Thermodynamic Performance of Organic Rankine Cycle (ORC) (작동유체에 따른 유기랭킨사이클(ORC)의 열역학적 성능에 관한 연구)

  • Kim, Kyoung-Hoon
    • Journal of Hydrogen and New Energy
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    • v.22 no.2
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    • pp.223-231
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    • 2011
  • The thermal efficiency of energy-to-power conversion becomes uneconomically low when the temperature of heat source drops below $370^{\circ}C$. ORC (Organic Rankine Cycle) has attracted much attention in last few years due to its potential in reducing consumption of fossil fuels and relaxing environmental problems, and its favorable characteristics to exploit low-temperature heat sources. In this work thermodynamic performance of ORC using nine working fluids is comparatively assessed. Special attention is paid to the effect of system parameters such as turbine inlet temperature and pressure on the characteristics of the system such as volumetric flow rate and quality at turbine exit, latent heat, net work as well as thermal efficiency. Results show that in selection of working fluid it is required to consider various criteria of performance characteristics as well as the thermal efficiency. Results also show that the system efficiencies become same irrespective of kind of working fluid when the temperature of heat source decreases to low range.

The Effect on COVID-19 Infection Control Practice of Nurses who Work in Working Sites with Negative Pressure Isolation Rooms (음압격리병실이 있는 부서에서 근무하는 간호사의 코로나19 감염관리 수행에 영향을 미치는 요인)

  • Park, Min Ji;Lee, Yun Mi
    • Journal of Korean Critical Care Nursing
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    • v.15 no.1
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    • pp.35-46
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    • 2022
  • Purpose : This study aimed to identify the factors affecting coronavirus disease 2019 (COVID-19) infection control practices of nurses in negative pressure isolation rooms. Methods : The participants were 150 nurses working in three hospitals with negative pressure isolation rooms. Data were collected using structured questionnaires and analyzed using an independent t-test, one-way ANOVA, Scheffé test, Pearson correlation coefficients, and multiple regression analysis using the SPSS/WIN 26.0 program. Results : Factors significantly influencing the subject's COVID-19 infection control practice include Being married (𝛽=.18, p =.016), working in a ward with negative pressure isolation rooms (𝛽=.44, p <.001), working in an ICU with negative pressure isolation rooms (𝛽=.27, p =.010), COVID-19 infection control attitude (𝛽=.28, p =.001), anxiety for COVID-19 (𝛽=.30, p <.001). The explanatory power of these variables for COVID-19 infection control practice was 24.6% (F=8.67, p <.001). Conclusion : It is expected that strategies that utilize positive attitudes which believe that COVID-19 disease may be overcome by COVID-19 infection control practice will help improve emerging infectious diseases infection control practice.

FIELD CONTROL MACHINE IN THE RECYCLED VINYL RAIL

  • I. J. Jang;S. S. Do;Park, Y. W.
    • Proceedings of the Korean Society for Agricultural Machinery Conference
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    • 2000.11c
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    • pp.722-728
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    • 2000
  • This study of field control machine in the recycled vinyl rail is gantry crane type and promoting agricultural automatization through self-controlled spraying, harvesting and conveyance. In addition to, that control machine could get a cost and labor reduction effect through automatization and make better environment by preventing farmers from agrichemical damage, accidents and recycling wasted vinyl. That machine is able to be divided as traveling, spraying, harvesting and conveyance sections. In driving section consists of girder frame, carrier, rail, control system, driving system, working machine, rail and loading device for working machine. This machine has following advantages to be able to bring a big innovation in the agricultural industry. I) Accurate performance is able to be done by proper positioning due to based on the rails. 2) The soil is not made hard like heavy tractor 3) The wheel is not sank into the soil and slipped well under rain like heavy tractor. Therefore, weather and soil situation could not affect working condition. 4) Complete unmanned control and 24hours-working are available due to traveling on the rails. 5) It could use various energy resources like not only liquid fuel but also solar, common electronic power due to traveling on the rails.

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Analysis of HFC-245fa organic Rankine cycle for geothermal power generation (지열 발전을 위한 HFC-245fa 유기 랭킨 사이클의 성능해석)

  • Baik, Young-Jin;Kim, Min-Sung;Chang, Ki-Chang;Yoon, Hyung-Kee;Lee, Young-Soo;Ra, Ho-Sang
    • Journal of the Korean Society for Geothermal and Hydrothermal Energy
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    • v.5 no.1
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    • pp.1-6
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    • 2009
  • In this study, an ORC (Organic Rankine Cycle) is investigated for a low-temperature geothermal power generation by a simulation method. A steady-state simulation model is developed to analyze cycle's performance. The model contains a turbine, a pump, an expansion valve and heat exchangers. The turbine and pump are modelled by an isentropic efficiency. Simulations were carried out for the given heat source and sink inlet temperatures, and given flow rate that is based on the typical power plant thermal-capacitance-rate ratio. HFC-245fa is considered as a working fluid of the cycle. Simulation results, at the given secondary working fluids conditions, show that even though the power can be presented by both the evaporating temperature and the turbine inlet superheat, it depends on the evaporating temperature primarily.

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The Optimized Design of a NPC Three-Level Inverter Forced-Air Cooling System Based on Dynamic Power-loss Calculations of the Maximum Power-Loss Range

  • Xu, Shi-Zhou;He, Feng-You
    • Journal of Power Electronics
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    • v.16 no.4
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    • pp.1598-1611
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    • 2016
  • In some special occasions with strict size requirements, such as mine hoists, improving the design accuracy of the forced-air cooling systems of NPC three-level inverters is a key technology for improving the power density and decreasing the volume. First, a fast power-loss calculation method was brought. Its calculation principle introduced in detail, and the computation formulas were deduced. Secondly, the average and dynamic power losses of a 1MW mine hoist acting as the research target were analyzed, and a forced-air cooling system model based on a series of theoretical analyses was designed with the average power loss as a heat source. The simulation analyses proves the accuracy and effectiveness of this cooling system during the unit lifting period. Finally, according to an analysis of the periodic working condition, the maximum power-loss range of a NPC three-level inverter under multi cycle operation was obtained and its dynamic power loss was taken into the optimized cooling system model as a heat source to solve the power device damage caused by instantaneous heat accumulation. The effectiveness and feasibility of the optimization design based on the dynamic power loss calculation of the maximum power-loss range was proved by simulation and experimental results.