• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.294-297
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• 2014

A Shipboard power system consists of three or four diesel generator sets connected to a grid. In case of dual fuel diesel generator sets employed LNG ship as a prime mover, large amounts of electricity are required for electric propulsion, auxiliary machinery and accommodation facilities. The electrical connection between generators through a network, torsional vibration can lead power swings. In this paper, the influence on the network by the torsional vibration of diesel generator sets in grid operation were studied. The torsional vibration characteristics were investigated and analyzed through theoretical analysis and the vibration measurement and the results were presented.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.220-227
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• 2021

PCT (Power Cable Tunnel) and UT (Utility Tunnel), which are non-transport underground infrastructures, are mostly RC (Reinforced Concrete) structures, and their durability decreases due to the deterioration caused by carbonation over time. In particular, since the rate of carbonation varies by use and region, a predictive model based on actual carbonation data is required for individual maintenance. In this study, a carbonation prediction model was developed for non-transport underground infrastructures, such as PCT and UT. A carbonation prediction model was developed using multiple regression analysis and deep neural network techniques based on the actual data obtained from a safety inspection. The structures, region, measurement location, construction method, measurement member, and concrete strength were selected as independent variables to determine the dependent variable carbonation rate coefficient in multiple regression analysis. The adjusted coefficient of determination (Ra2) of the multiple regression model was found to be 0.67. The coefficient of determination (R2) of the model for predicting the carbonation of non-transport underground infrastructures using a deep neural network was 0.82, which was superior to the comparative prediction model. These results are expected to help determine the optimal timing for repair on carbonation and preventive maintenance methodology for PCT and UT.

• Proceedings of the KIEE Conference
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• 2001.10a
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• pp.110-112
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• 2001

본 논문에서는 전력선 통신 시스템의 전송신호가 비수용가로 전송되는 현상을 차단하기 위한 비접촉식 Blocking Filter를 유한요소법을 이용하여 해석하였다. 새로운 통신망 시스템이 연구되면서 기존의 전력케이블 망을 이용한 전력선 통신방식에 대한 연구가 이루어 졌으나, 전력선 통신이 서비스 지역 이외에 다른 지역으로 통신신호들이 전송될 수 있는 문제점이 제기되었으며, 또한 지정된 지역 내에서 최적화된 통신환경의 구성이 요구되었다. 따라서 본 논문은 타 지역으로의 신호 간섭을 차단하기 위한 비접촉식 Blocking Filter의 기본 모델을 제시하였으며, 이러한 비접촉식 Blocking Filter를 유한요소법을 기초로 한 전자장 수치해석 기법과 전송선 이론을 도입하여 신호 전송 특성을 해석하였다.

• Proceedings of the KIEE Conference
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• 2008.11a
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• pp.214-216
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• 2008

현재 전력수급기본계획은 전국을 한일권으로 하여 발전계획을 수립하고 송변전설비계획을 수립하고 있다. 그러나 발전설비와 송변전설비는 하나의 망으로 연결되어 상호 보완적 영향을 주기 때문에 수급계획시 두 설비를 동시에 평가하는 것이 무엇보다 중요하다. 본 논문에서는 혼합정수형 선형계획법(MIP)을 이용하여 발송전 전력설비를 통합적으로 최적 구성할 수 있는 방안에 대하여 분석하였다. 전력수급기본계획 수립시 제출된 건설의향설비에 대해 송변전설비와 통합하여 적정 예비율을 갖는 최적설비 구성방안을 수립하고, 이때의 설비투자비와 운전비를 분석하였다.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.39A no.1
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• pp.62-64
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• 2014

We propose joint employment of power control and almost blank subframes (ABSF) for femtocells to mitigate the interference of femto-cells to a macrocell in heterogeneous networks. We obtained improved performance in terms of both femtocells capacity and reduced interference by computer simulations while we have marginally decreased overall network capacity compared to possibly maximum capacity.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.242-243
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• 2011

우리나라의 전력 계통은 수도권에 부하가 집중되어 있는 반면에 발전 설비는 비수도권에 위치해서 대규모 북상 조류가 발생한다. 이런 대규모의 장거리 전력 전송은 계통의 안정도를 떨어뜨리고 사고시 전력 계통에 불안정을 야기할 수 있다. 때문에 이를 방지하기 위해 송전전력을 제한하게 되고 그로 인한 혼잡비용이 발생한다. 전압형 BTB(Back-to-Back) HVDC의 경우 유효전력과 무효전력의 독립적인 제어가 가능하므로 전압형 BTB HVDC를 수도권 전력 계통에 투입시켜 무효전력을 보상해줄 수 있다. 무효전력을 보상해주면 수도권으로의 융통전력이 더 증가하게 되고 그로 인한 혼잡비용을 절감시킬 수 있다. 본 논문에서는 PSS/E를 이용하여 전압형 BTB HVDC를 수도권 전력망에 투입하여 융통전력을 계산하고 이를 토대로 탄소세를 고려한 혼잡 비용절감 효과를 알아본다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.13 no.5
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• pp.77-83
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• 2013

Nowadays, the limitation of Lighting control and management skills is the excessive cost of equipments, the operational difficulties and wasting energy. To solve this problem is in need of communication and management S/W that is worked out complexly well as a information system of smart lighting energy, which is loaded wireless network facility. This paper made a study od the energy saving technology through energy monitoring and we developed LEIS(Lighting Energy Information Sysem) to converge this one. LEIS is monitoring and control lighting energy data that is collelcted from sensors by Zigbee mesh network and shows lighting use information by visualization to users. It is consists of lighting energy information data base based on LEM(Lighting Energy Metering) information and LEIS Web application, provide function scenario to manage energy optimization through LEIS.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.3
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• pp.1-12
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• 2021

Technologies for an MVDC(medium voltage direct current) distribution system are being considered as an effective alternative to overcome the interconnection delay issues of PV systems. However, the implementation of a DC distribution system might lead to economic problems because of the development of DC devices. Therefore, this paper deals with the scale of a PV plant based on its capacity and proposes hosting-capacity models for PV systems to establish a network to evaluate the feasibility of an MVDC distribution system. The proposed models can be classified as AC and DC distribution systems by the power-supply method. PV systems with hundreds of MW, dozens of MW, and a few MW can be categorized as large-scale, medium-scale, and small-scale models, respectively. This paper also performed modeling for an economic evaluation of MVDC distribution system by considering both the cost of AC and DC network construction, converter replacement, operation, etc. The profit was composed of the SMP and REC rate of a PV plant. A simulation for economic evaluation was done for the MVDC distribution system using the present worth and equal-principal costs repayment method. The results confirmed that the proposed model is a useful tool to evaluate economic issues of a DC distribution system.

• Journal of the Korean Institute of Intelligent Systems
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• v.19 no.6
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• pp.766-772
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• 2009

Generally, wind industry has been oriented to large power systems which require large windy areas and often need to overcome environment restrictions. However, small-scale wind turbines are closer to the consumers and have a large market potential, and much more efforts are required to become economically attractive. In this paper, a prototype of a small-scale urban wind generation system for battery charging application is described and a neural network based MPPT(Maximum Power Point Tracking) algorithm which can be effectively applied to urban wind turbine system is proposed. Through Matlab based simulation studies and actual implementation of the proposed algorithm, the feasibility of the proposed scheme is verified.

• Proceedings of the KIPE Conference
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• 2017.11a
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• pp.173-174
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• 2017

최근 태양광, Energy Storage System(ESS) 등의 신재생에너지의 발전과 직류기반의 디지털 기기가 늘어나면서 직류전력망에 대한 관심이 증가하고 있다. 이에 따라 DC-DC 컨버터의 필요성이 증가하고 있다. DC-DC 컨버터의 경우 동기식과 비동기식의 스위칭 방식을 고려할 수 있으며, 각 방식에 따라 전류가 다이오드 혹은 스위치를 통해 흐르게 된다. 본 논문에서는 동기 및 비동기 컨버터의 효율을 실제 실험을 통하여 비교 분석하였다.