• The Transactions of the Korean Institute of Electrical Engineers P
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• v.65 no.2
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• pp.94-100
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• 2016

A virtual power plant (VPP) technology is a cluster of distributed generation installations. VPP system is that integrates several types of distributed generation sources, so as to give a reliable overall power supply. Virtual power plant systems play a key role in the smart grids concept and the move towards alternative sources of energy. They ensure improved integration of the renewable energy generation into the grids and the electricity market. VPPs not only deal with the supply side, but also help manage demand and ensure reliability of grid functions through demand response (DR) and other load shifting approaches in real time. In this paper, utilizing a variety of distributed generation resources(such as emergency generator, commercial generator, energy storage device), activation scheme of the virtual power plant technology. In addition, through the analysis of the domestic electricity market, it describes a scheme that can be a virtual power plant to participate in electricity market. It attempts to derive the policy support recommendation in order to obtain the basics to the prepared in position of power generation companies for the commercialization of virtual power plant.

• Nuclear Engineering and Technology
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• v.49 no.2
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• pp.327-334
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• 2017

Common-cause failure (CCF) events can significantly impact the availability of safety systems of nuclear power plants. For this reason, the International Common Cause Data Exchange (ICDE) project was initiated by several countries in 1994. Since 1997 it has been operated within the Organisation for Economic Co-operation and Development (OECD)/Nuclear Energy Agency (NEA) framework and has successfully been operated over six consecutive terms (the current term being 2015-2017). The ICDE project allows multiple countries to collaborate and exchange CCF data to enhance the quality of risk analyses, which include CCF modeling. As CCF events are typically rare, most countries do not experience enough CCF events to perform meaningful analyses. Data combined from several countries, however, have yielded sufficient data for more rigorous analyses. The ICDE project has meanwhile published 11 reports on the collection and analysis of CCF events of specific component types (centrifugal pumps, emergency diesel generators, motor operated valves, safety and relief valves, check valves, circuit breakers, level measurement, control rod drive assemblies, and heat exchangers) and two topical reports. This paper presents recent activities and lessons learnt from the data collection and the results of topical analysis on emergency diesel generator CCF impacting entire exposed population.

• Proceedings of the KIPE Conference
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• 2018.07a
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• pp.180-182
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• 2018

직류배전 시스템은 신재생에너지 및 ESS(Energy Storage System)와의 결합으로 높은 에너지 이용효율을 가질 수 있다. 이러한 직류배전 시스템은 기존 교류계통을 통해 구성되며, 다양한 디지털 부하가 연계되므로 교류계통 및 메인 PCS(Power Conversion System)에 문제가 발생했을 때를 대비하여 비상 전력 공급 시스템이 필수적으로 고려되어야 한다. 최근 직류배전에서 비상 전력 공급 시스템으로 큰 관심을 받고 있는 ESS는 초기 설치비용, 용량, 수명 등의 문제로 인해 단일로 비상 전력 공급 시스템을 구성하기에 어려움이 있다. 때문에 기존에 이미 많이 설치되어 있는 비상발전기의 적용이 검토되어야 한다. 본 논문에서는 비상발전기와 ESS를 활용하여 양극성 저압직류배전에서 정전과 같은 사고 상황 발생 시 직류배전망의 전압을 빠르게 안정시킬 수 있는 시스템과 그 운영기법을 제안하였고, PSIM 시뮬레이션을 통하여 타당성을 검증하였다.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.42-48
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• 2020

This research illustrates how the hybrid engine system comprising of a two-cycle reciprocal engine with an integrated generator and a battery is prepared for the design process. The purpose of this research is to increase flight endurance taking advantage of the high energy density of hybrid propulsion systems as well as to cope with current environmental issues by reducing fossil fuel. The hybrid system is designed to offer 6 kW power, and the power can be adjusted by controlling the engine's RPM in accordance with load variations. In addition, the battery is adopted to offer extra electric power that this hybrid system cannot cover, and can function as the main power source in limited time in the case of an emergency situation. Besides that, the generator is directly mounted on an engine crank-shaft, and in turn, they can share the same RPM. Thus, it is hypothesized that this integration method can make a compact design possible by reducing space for the installation in the fuselage of UAVs.

• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.12 no.1
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• pp.1-6
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• 2016

Characteristics of exhaust from chimney of electricity generator are analyzed based on CFD when Waveguide-Below-Cutoff (WBC) array is installed in order to achieve the certain level of electromagnetic pulse (EMP) shielding. The main purpose is prediction of average and maximum velocity of exhaust. The results reveal that: 1) When the specification of waveguide is given as 80-diameter, 400-length, and the gap of 20 mm, the shielding effectiveness (SE) is 140dB. The average and maximum velocity of exhaust in the chimney with WBC Array can be represented as exponential functions. 2) As the number of WBC increases, the velocity in the chimney dwindles. 3) Under the situation that WBC with 80 mm diameter is located at intervals of 20 mm, the average velocity can be approximated by $25.5344{\times}e^{(-0.0098{\times}N_{WBC})}$ with input velocity of 15 m/s. In addition, the determination coefficient is 0.915, which is sufficiently high.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.6
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• pp.8-12
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• 2017

This paper presents the mobile phone case for self-power generation and recharge for emergency calls or text messages at the discharge of a battery. If the user shakes his smart phone case, the interaction of electromagnetic coil and permanent magnet in an electric generator produces electric energy, which charges the lithium-ion battery. This enables the user to give a few calls or text messages. In addition, the vibration energy from humans walking at a frequency of 2 ~ 3Hz charges the battery. The electric generator was simulated using MAXWELL, a commercial electromagnetic analysis program, to analyze the electric power generation. Finally a prototype of the mobile phone case for self-power generation was built based on the analysis and its performance was verified.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.5 no.3
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• pp.563-572
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• 2001

A conventional motor in a crane has a taco generator to feed back the number of turns to a main controller. The taco generator is contacted to a motor shaft through the coupling. Errors in a crane have often occurred because the coupling has worn out while the motor is turning. In this paper, we design the device of the frequency to voltage transducer in a motor. The device is composed of a rotary encoder, a speed measurement using PIC16F84 controller, a display, and a direction-decision block. The rotation of a motor is recognized by the rotary encoder and microcontroller counts the number of turns of a motor. The emergency signal is generated if the frequency goes over or below the speed limit of a motor. And the device can acknowledge the rotation direction of the motor after 6。 rotation. The simulation results and the test for a implemented device have shown that the transducer of a frequency to a voltage can replace a taco generator in a crane.

• Journal of rehabilitation welfare engineering & assistive technology
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• v.11 no.4
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• pp.331-338
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• 2017

In this study, a portable x-ray generator was manufactured and a real-time image acquisition system was constructed using the image intensifier from the generated generator. We have developed a real - time position error verification system that can verify whether the artificial joint position is different from the initial image from the acquired image. The template image of the region of interest is extracted from the reference image using the pattern matching technique and compared with the image to be compared. As a result, It is shown that real - time position error verification is achieved by displaying the difference angle. This system is portable type, has a self-shielding facility, and the output of the irradiation device can be manufactured in a small size of 1kw and can be used as a portable type. In case of emergency patients in the non-destructive field for industrial use, It has proved effective for use in small areas such as feet.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.11
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• pp.2534-2539
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• 2015

Method for regulating voltage using a generator voltage regulating device (AVR) is divided in an existing analog system and a digital replacement. Typically, to adjust the voltage by using a brushless excitation system of the type to be reduced for a voltage change under all. The control method of the AVR as a PID (proportional-integral-differential) control method is widely used. However, the control scheme is to reduce the transient response of the control parameters of the controller to the control object. Therefore, if the control target should change, there is a problem, reset the parameters of the controller again. In this study, without having to reset the parameters of the controller for the parameter variations to be controlled iPID (intelligent PID) using a controller designed to obtain a generator AVR system voltage variation is small in response to full load is applied to and through simulations and experiments improved transient response.

• Journal of Advanced Navigation Technology
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• v.22 no.6
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• pp.514-521
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• 2018

COSPAS-SARSAT 406 MHz emergency beacons include ELTs for aviation, EPIRBs for maritime, and PLBs for individuals in distress. They are used to sending messages encoded on 406 MHzdistress frequency and sending alertsfor search and rescue in distress. C/S T.001 and T.018 are COSPAS-SARSAT technical documents. They include basic technical information needed for developing beacons, howmessages are constructed, and test methods for type approval. COSPAS-SARSAT systems that use existing low earth orbit (LEO) and geostationary earth orbit (GEO) satellites do not have a return link service (RLS). So, the survivors could not confirm whether the distress signal was sending or not. However, a new medium earth orbit (MEO)satellite system has been added to thissystem, allowing confirmation through the RLS function. This paper analyzed C/S T.001 and T.018 needed to develop navigation structuresthat incorporated improved PLB of 406 MHz, a homing signal generator of 121.5 MHz, and a VHF AM transmitter for aviation of 243 MHz.