• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.2
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• pp.1175-1178
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• 2004

On-line partial discharge(PD) monitoring system has been developed to monitor in operating large motor stator insulations. This system makes use of remote diagnosis techniques for the evaluation of PD activity in the control center of thermal power plant. This system can be remotely accessed via a modem to build database, analyze status and interpret the pattern of PD activity. A personnel computer is generally connected to ten motors to continuous measurement of the PD activity. The test data can be easily interpreted by a maintenance staff. For assessing the condition of stator winding in motors, this system ensures a reliable measurement and accurate estimation. Capacitive couplers used for on-line PD measurement have been 80pF. The maximum PD magnitude(Qmax), PD pattern and normalized quantity number(NQN) were performed by this system.

• 한국정보통신학회논문지
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• 제11권10호
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• pp.1821-1827
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• 2007

본 논문에서는 복잡한 다중경로를 갖는 가정 전력선에 대한 채널 모델을 분석적 방법으로 전달함수를 분석하였다. 전력선의 배경잡음을 고려한 채널 모델 전달함수를 OFDM 시스템에 적용하였으며, QPSK 및 16-QAM 변조신호에 대한 BER 관계를 분석하였다. 광대역 전력선 통신시스템에 대한 OFDM 변조의 이득 관계를 제시함으로서 OFDM을 적용한 특성 파라미터를 예측할 수 있다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2006년도 하계학술발표대회 논문집
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• pp.1150-1155
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• 2006

In a heating control system, the indoor temperature controller transfers temperature signals inputed from the temperature sensor and the user to the valve controller. The valve controller recieves these signals then the valve controller controls the valve driving motor on two position control and controls the indoor temperature. When setting up a new valve driving motor from a long distance it is necessary to set up a new valve controller. But occasionary, due to construction, it is impossible to wire between the existing valve controller and the new valve controller. In this situation, the new and existing valve controllers can communicate via power line communication. In this paper it is proposed heating control system controls on two position control via power line communication.

• 한국항행학회논문지
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• 제17권2호
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• pp.202-207
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• 2013

본 논문에서는 병렬 연결된 전송선로를 이용하여 고 비율 비대칭 전력 분배기를 설계하였다. 병렬 연결된 전송선로는 마이크로스트립 기술로 구현하기 어려운 낮은 임피던스의 전송선로를 높은 임피던스 전송선로로 구현하는 방법이다. 비율 비대칭 분배기 구현 시 사용되는 낮은 임피던스를 구현하기 위하여 병렬 연결된 전송선로를 이용함으로서 구현을 쉽게 할 수 있었다. 이러한 설계방법의 타당성을 보이기 위해서 중심 주파수 1 GHz에서 10:1 비율의 비대칭 전력 분배기를 제작하였고, 이것의 특성은 시뮬레이션과 거의 동일함을 확인하였다.

• Nuclear Engineering and Technology
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• 제54권10호
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• pp.3732-3744
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• 2022

To investigate the effects of ocean conditions on the thermal stress and deformation caused by thermal stratification of a pressurizer surge line in a floating nuclear power plant (FNPP), the finite element simulation platform ANSYS Workbench is utilized to conduct the fluid-solid-thermal coupling transient analysis of the surge line under normal "wave-out" condition (no motion) and under ocean conditions (rolling and pitching), generating the transient response characteristics of temperature distribution, thermal stress and thermal deformation inside the surge line. By comparing the calculated results for the three motion conditions, it is found that ocean conditions can significantly improve the thermal stratification phenomenon within the surge line, but may also result in periodic oscillations in the temperature, thermal stress, and thermal deformation of the surge line. Parts of the surge line that are more susceptible to thermal fatigue damage or failure are determined. According to calculation results, the improvements are recommended for pipeline structure to reduce the effects of thermal oscillation caused by ocean conditions. The analysis method used in this study is beneficial for designing and optimizing the pipeline structure of a floating nuclear power plant, as well as for increasing its safety.

• Smart Structures and Systems
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• 제22권1호
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• pp.81-94
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• 2018

Automatic Generation Control (AGC) has functionally controlled the interchange power flow in order to suppress the dynamic oscillations of frequency and tie-line power deviations as a perturbation occurs in the interconnected multi-area power system. Furthermore, Flexible AC Transmission Systems (FACTS) can effectively assist AGC to more enhance the dynamic stability of power system. So, Static Synchronous Series Compensator (SSSC), one of the well-known FACTS devices, is here applied to accurately control and regulate the load frequency of multi-area multi-source interconnected power system. The research and efforts made in this regard have caused to introduce the Fractional Order Proportional Integral Derivative (FOPID) based SSSC, to alleviate both the most significant issues in multi-area interconnected power systems i.e., frequency and tie-line power deviations. Due to multi-objective nature of aforementioned problem, suppression of the frequency and tie-line power deviations is formularized in the form of a multi-object problem. Considering the high performance of Multi Objective Bees Algorithm (MOBA) in solution of the non-linear objectives, it has been utilized to appropriately unravel the optimization problem. To verify and validate the dynamic performance of self-defined FOPID-SSSC, it has been thoroughly evaluated in three different multi-area interconnected power systems. Meanwhile, the dynamic performance of FOPID-SSSC has been accurately compared with a conventional controller based SSSC while the power systems are affected by different Step Load Perturbations (SLPs). Eventually, the simulation results of all three power systems have transparently demonstrated the dynamic performance of FOPID-SSSC to significantly suppress the frequency and tie-line power deviations as compared to conventional controller based SSSC.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2007년도 추계학술대회 논문집
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• pp.1515-1521
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• 2007

In this paper, a unified regenerative inverter system for railway with DC line voltage simulator is proposed. In order to determine the operation characteristics of the regenerative inverter, the DC line voltage simulator is proposed. The DC line voltage simulator, which is based on the AC-DC PWM converter, varies the DC voltage according to the fluctuating voltage which is measured in the actual DC line. The suitable operating point of the regenerative inverter can be estimated from the simulation result. The regenerative inverter operates two modes. When the DC line voltage exceed the operating point, already set up, it works as regenerative inverter to return the excessive power of DC line to the grid. When the DC line voltage is under the operating point, it works as active power filter to compensate harmonic currents. In this paper, the control algorithm of the DC line voltage simulator and that of the regenerative inverter is proposed.

• 전기학회논문지
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• 제67권9호
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• pp.1125-1140
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• 2018

This paper analyzes robotic technology developed for live-line electricity distribution and its applicability to domestic environment. In doing so, available robotic systems developed for the live-line work are thoroughly investigated and compared in terms of from robotic functionality to economic feasibility. To assess the technology readiness for domestic live-line robot, the rubber gloves based direct live-line engineering methods have been also analyzed and mapped into robotic technology requisites. The results are expected as a fundamental data to help with solving the safety and economics issues when considering development and introduction of compact live-line robot for complex domestic electricity distribution environment.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.63-65
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• 2005

Korea Electric Power Corporation (KEPCO) is in charge of the operation and the maintenance for transmission lines and substations in Korean power system which is under the deregulation power market. KEPCO has a main constrain of transmission line toward SEOUL area which is a capital of KOREA because SEOIJL is a huge load of Korean power system. The Korea Electric Power Research Institute (KEPRI)), a division of KEPCO was tasked to study the ATC enhancement of transmission line toward SEOUL using a new line or/and FACTS. This paper summarizes the results of those studies, enhancing the ATC and evaluating the economics.

• 전자공학회논문지D
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• 제34D권10호
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• pp.24-31
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• 1997

A new design method of stable RF power amplifier using 3dB coupled line is proposed in this thiesis. The proposed method of broadband matching consist of resistive matching circuits at low frequency and lossless matching circuits at microwave band. This design method increase the stability of an amplifier and is suitable for interstage matching. When high power amplifier is designed using this method for PCS base transceiver station, the measured resutls show thst the gain of 18.5dB, and 9W (39.5dBm) output power. We use motorola's MRF6401 for medium power and MRF 6402 for large power and cascaded them.