• Journal of Electrical Engineering and Technology
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• 제10권1호
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• pp.1-7
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• 2015

The industry has rapidly growth and energy supply technology advanced are become main factor which to contribute of the harmonic losses. This problem is one aspect that may affect the capability of the transmission line and also to the efficiency of electricity. This paper proposes a new scheme to allocate the cost pertaining to transmission loss due to harmonics. The proposed method, called as Generalized Harmonic Distribution Factor, uses the principle of proportional sharing method to allocate the losses among the transmission users especially for industry consumers. The IEEE 14- and 30 bus test system is used to compare the proposed method with existing method. The results showed that the proposed method provided a scheme better in allocating the cost of transmission loss, which could encourage the users to minimize the losses.

• 한국태양에너지학회 논문집
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• 제34권1호
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• pp.64-71
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• 2014

This study is to perform economic analysis of a PVT-GSHP (Photovoltaic Thermal-Ground Source Heat Pump) system compared to the conventional system which consists of a boiler and a chiller. This research has simulated, developed and analyzed four systems for application in a residential and an office building which was based on the hourly EPI (Energy Performance Index, $kWh/m^2yr$). Case 1 includes a boiler and a chiller to meet heating and cooling demands for a house. Case 2 is the same conventional system as Case 1 for a office. Case 3 is simple summation of Case 1 and 2. And Case 4 is utilizing a PVT-GSHP to meet the combined loads of the house and office. The economic evaluation study was based on IEA ECBCS Annex 54 subtasks C economic assessment methods. This study indicated that PVT-GSHP system can save a building's energy up to 53.9%. Also the SPB (Simple Payback) of the PVT-GSHP system with 0%, 50% initial incentive was 14.5, 6.7 year respectively.

• Geomechanics and Engineering
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• 제24권1호
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• pp.29-42
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• 2021

The utilization of buildings can be improved by extending them vertically. However, the added load of the extension might require building foundations to be underpinned; otherwise, the loads on the foundations might exceed their bearing capacity. In this study, a preloading method was presented aiming at transferring partial loads from existing piles to underpinning piles. A pneumatic-type model preloading device was developed and used to carry out centrifuge experiments to evaluate the load-displacement behavior of piles, the pile-soil interaction during preloading, and the additional loading caused by vertical extension. The results showed that the preloading devices effectively transfer load from existing piles to underpinning piles. In the additional loading test of group piles, the load-sharing ratio of a pile increased with its stiffness. The load-sharing ratio of a preloaded micropile was less than that of a non-preloaded micropile as a result of the reduction in axial stiffness caused by preloading before additional loading. Therefore, a slight reduction of the load-sharing capacity of an underpinning pile should be considered if the preloading method is applied. Further, two full scale preloading devices was developed. The devices preload underpinning piles and thereby produce reaction forces on a reaction frame to jack existing piles upward, thus transferring load from the existing piles to the underpinning piles. Specifically, screw-type and hydraulic-jack type devices were developed for the practical application of foundation underpinning during vertical extension, and their operability and load transfer effect verified via full-scale structural experiments.

• Current Optics and Photonics
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• 제1권4호
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• pp.315-324
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• 2017

In recent years, multicast services such as high-definition television (HDTV), video conferencing, interactive distance learning, and distributed games have increased exponentially, and wavelength-division multiplexing (WDM) networks are considered to be a promising technology due to their support for multicast applications. Multicast survivability in WDM networks has been the focus of extensive attention since a single-link failure in an optical network may result in a massive loss of data. But the improvement of network survivability increases energy consumption due to more resource allocation for protection. In this paper, an energy-efficient multicast algorithm (EEMA) is proposed to reduce energy consumption in WDM networks. Two cost functions are defined based on the link state to determine both working and protection paths for a multicast request in WDM networks. To increase the number of sleeping links, the link cost function of the working path aims to integrate new working path into the links with more working paths. Sleeping links indicate the links in sleep mode, which do not have any working path. To increase bandwidth utilization by sharing spare capacity, the cost function of the protection path is defined to use sleeping fibers for establishing new protection paths. Finally, the performance of the proposed algorithm is evaluated in terms of energy consumption, and also the blocking probability is evaluated under various traffic environments through OPNET. Simulation results show that our algorithm reduces energy consumption while maintaining the quality of service.

• 조명전기설비학회논문지
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• 제28권5호
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• pp.68-75
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• 2014

Cascaded applications of surge protective devices(SPDs) are required in order to reduce the stress on the electrical and electronics equipment being protected, and the energy coordination between the cascaded SPDs is very important. This paper deals with the experimental results obtained from the installation conditions of full-scale SPDs. The energy coordination between the upstream Class I SPD and the downstream Class II SPD was measured using a $10/350{\mu}s$ impulse current due to direct lightning flashes. The distances between the cascaded SPDs were 3, 10, and 50m, and the maximum test current was 12.5kA. As a result, the energy sharing between cascaded SPDs was dependent on the voltage protection level of each SPD and the distance between two SPDs. An overview of how to select SPD ratings in applications of cascaded SPDs system was discussed based on the energy coordination between the two SPDs. The proposed test results for the energy coordination between two-stage cascaded SPDs can be used in effective applications of SPDs.

• 한국산업융합학회 논문집
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• 제25권6_3호
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• pp.1199-1206
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• 2022

Fossil fuels are one of the various energy sources used by humans, and industrial development has been achieved by relying on fossil fuels for a long time in the past. In order to respond to the depletion of fossil fuels and climate change, the world is trying to build an eco-friendly energy ecosystem. Research on efficiency improvement using renewable energy and ESS in various ways for energy conversion is being promoted. In this paper, a microgrid for industrial complexes was designed, constructed, and demonstrated. It was operated in two modes: an independent mode that each plant generates and uses independently and a connected operation mode that allows energy sharing between factories. In the case of independent mode, PV and PCS were intermittently stopped and restarted according to the status change of SoC section of each site. But, in the case of the connected operation mode, stable power supply was confirmed through power transaction through the operation of the entire SoC. This paper presented and verified an algorithm to stably supply power to industrial complexes consisting of various consumers with different load characteristics.

• 한국정보과학회논문지:컴퓨팅의 실제 및 레터
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• 제16권11호
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• pp.1086-1090
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• 2010

최근 센서 네트워크의 활용 분야가 증가함에 따라 시스템을 효율적으로 운용하기 위한 다양한 연구들이 진행되고 있다. 대표적인 연구로 센서가 에너지를 소모하는 데 있어서 큰 비중을 차지하는 데이터 전송 비용을 줄이기 위해서 질의 최적화 기법이 연구되고 있다. 본 논문에서는 무선 센서 네트워크 환경에서 다수의 영역 질의가 발생하였을 때 질의들 간의 부분 결과를 공유함으로써 에너지 효율적인 다중 질의 처리 기법을 제안하였다. 제안하는 기법은 그리드 구조를 이용하여 직관적인 위치 판별을 가능케하여 주변 노드들과의 불필요한 메시지 전송을 줄이고, 중복된 영역을 인지함으로써 효율적인 데이터 공유가 가능하다. 제안하는 기법의 우수성을 보이기 위해 기존에 제안된 기법과 시뮬레이션을 통해 성능을 비교평가 하였다. 그 결과, 다중 질의 처리 시 발생하는 에너지 소모가 기존 기법에 비해 약 65% 감소되었다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2023년도 학술발표회
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• pp.245-245
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• 2023

This paper examines the extent to which the Mekong River Basin countries have achieved socioeconomic benefits based on regional cooperation through the Greater Mekong Subregion (GMS) Program, focusing on hydropower development and the Mekong Power Grid. This study pays attention to the time period from 2012 to 2022. The benefit sharing approach is employed to evaluate the extent to which hydropower development and the Mekong Power Grid have contributed to the regional energy trade in the GMS program. The GMS program was launched by the Asian Development Bank (ADB) in 1992, and the Chinese provinces of Yunnan and Guangxi, Myanmar, Lao PDR, Thailand, Cambodia, and Vietnam have taken an active part in the program. The goals of the GMS program are to achieve poverty alleviation, economic development, and regional cooperation in various sectors, including energy, tourism, and transportation. The GMS Economic Cooperation Program Strategic Framework 2030 (GMS-2030), in 2021, provides a new framework for prosperous and sustainable development in the river basin. In the energy sector, the GMS program has been instrumental in facilitating hydropower development and creating the Mekong Power Grid with the Regional Grid Code (RGC), contributing to economic benefits and promoting regional trade of hydroelectricity. It is argued that the GMS program has enhanced regional cooperation between the riparian countries. Despite such achievements, the GMS program has faced challenges, including the gap of economic development between the riparian countries, socioeconomic and environmental concerns regarding hydropower development between the Upper and Lower Mekong countries, and geopolitical tensions from the US-China rivalry. These challenges should adequately be addressed within the program, which can guarantee the sustainability of the program for the river basin.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2016년도 전력전자학술대회 논문집
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• pp.85-86
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• 2016

본 논문은 스위칭 주파수 스펙트럼 분석에 기반한 모듈형 병렬 양방향 DC-DC 컨버터의 전류분배 제어방법을 제안한다. 병렬 DC-DC 컨버터 각 모듈의 전류분배 균일도 향상은 동작안정성 확보, 효율 및 신뢰성 향상을 위해 매우 중요한 요소이다. 드룹 제어의 적용을 통해 별도의 통신연결 없이 각 병렬모듈간 전류 분배량 제어가 가능하지만, 선로 저항의 차이나 측정 소자의 편차가 발생할 경우 각 모듈간 균일한 전류분배가 어려운 문제가 존재한다. 각 모듈간 전류분배를 위해 각 개별모듈의 입력 전류에 존재하는 스위칭 주파수 성분만을 분석하여 병렬 모듈 사이의 전류분배 차이를 검출하고, 그 차이를 최소화 하도록 드룹 이득을 단계적으로 조절하는 제어 알고리즘을 제안한다. 제안된 제어 알고리즘은 에너지 저장장치와 연계된 380V급 DC 배전 시스템 모델을 대상으로 검증하였다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제14권3호
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• pp.284-299
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• 2014

Coarse-grained reconfigurable architecture (CGRA)-based multi-core architecture aims at achieving high performance by kernel level parallelism (KLP). However, the existing CGRA-based multi-core architectures suffer from much energy and performance bottleneck when trying to exploit the KLP because of poor resource utilization caused by insufficient flexibility. In this work, we propose a new ring-based sharing fabric (RSF) to boost their flexibility level for the efficient resource utilization focusing on the kernel-stream type of the KLP. In addition, based on the RSF, we introduce a novel inter-CGRA reconfiguration technique for the efficient pipelining of kernel-stream on CGRA-based multi-core architectures. Experimental results show that the proposed approaches improve performance by up to 50.62 times and reduce energy by up to 50.16% when compared with the conventional CGRA-based multi-core architectures.