• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2005년도 춘계학술대회
• /
• pp.463-466
• /
• 2005

As the distributed generation becomes more reliable and economically feasible, it is expected that a higher application of the distributed generation units would be interconnected to the existing grids. This new generation technology is linked to a large number of factors like economics and performance, safety and reliability, market regulations, environmental issues, or grid connection constrains. KEPOD (Korea Electric Power Corporation) is performing the project to develope the Distributed Micro Gas Turbine (MGT) technologies by using Swine BID-ENERGY. This paper describes the plans and strategies for the renewable energy of MGT on actual grid-connection under Korean situations. KEPOD also, has a research plan on bio-gas pretreatment system applicable to our domestic swine renewable resources and is performing concept design of pilot plant to test grid operation. In addition, this testing will be conducted in order to respond to a wide variety of needs for application and economic evaluation in the field of On-site generation.

• 전력전자학회논문지
• /
• 제19권2호
• /
• pp.194-200
• /
• 2014

In DC micro-grid system energy storage systems (ESS) are responsible for storing energy and balancing power. Also, control target of the bidirectional DC-DC converter(BDC) for ESS should be changed depending on the operating mode. During the grid connected mode, the BDC controls the battery current or voltage. When a grid fault occurs, the BDC should change the control target to regulate the DC-bus. The BDC with conventional control method may experience large transient state during the mode change. This paper proposes a control method of BDC for ESS. The proposed control method is able to provide autonomous and seamless mode transfer by a variable current limiter. To validate the proposed concept, simulation results using PSIM and experimental results from a 2kW prototype are provided.

• 한국산학기술학회논문지
• /
• 제19권7호
• /
• pp.258-264
• /
• 2018

본 논문은 마이크로 그리드 최적 운영을 위해 Differential Search (DS) 알고리즘을 적용하였다. DS 알고리즘은 이주하는 생물의 유사 브라운 운동 형태의 임의보행 (random-walk)을 모의하여 개발된 알고리즘이다. DS 알고리즘은 다른 최적화 알고리즘과 달리 한 개 이상의 개체를 동시에 사용 할 수 있고, 유사 최적해중에서 전역 최적 해를 선별하는 직진성 특성으로 multi-modal 함수들의 해법을 위한 성공적인 탐색 전력을 지니고 있으며, 높은 비선형성과 불연속성을 갖는 전력계통의 다른 분야에도 효율적으로 적용될 수 있다. 마이크로 그리드 시스템은 풍력 발전기, 디젤발전기, 연로전지 및 태양광 발전기로 구성된다. 풍력 발전기는 가변 출력특성을 이용하여 모델링 하였다. 연료비용과 연료가 전력으로 변환되는 경우의 효율을 포함시켜 시스템의 비용을 최소화 하였으며, 마이크로 그리드 단독 운용에 관해서만 분석하였다. 본 연구는 신재생 에너지원 기반의 마이크로 그리드의 최적 운영에 대해 코딩의 단순성, 빠른 수렴 속도, 정확성 및 효율성을 갖춘 DS 알고리즘을 적용하여 다른 알고리즘의 최적 값과 비교하였다.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2007년도 춘계학술대회
• /
• pp.585-588
• /
• 2007

As the distributed generation becomes more reliable and economically feasible, it is expected that a higher application of the distributed generation units would be interconnected to the existing grids. This new generation technology is linked to a large number of factors like economics and performance, safety and reliability, market regulations, environmental issues, or grid connection constrains. KEPCO (Korea Electric Power Corporation) is performing the project to develope the Distributed Micro Gas Turbine (MGT) technolgies by using Swine BIO-ENERGY. This paper describes the plans and strategies for the renewable energy of MGT on actual grid-connection under Korean situations. KEPCO also, has a research plan on bio-gas pretreatment system applicable to our domestic swine renewable resources and is performing concept design of pilot plant to test grid operation. In addition, this testing will be conducted in order to respond to a wide variety of needs for application and economic evaluation in the field of On-site generation.

• 신재생에너지
• /
• 제2권3호
• /
• pp.15-22
• /
• 2006

As the distributed generation becomes more reliable and economically feasible, it is expected that a higher application of the distributed generation units would be interconnected to the existing grids. This new market penetration using the distributed generation technology is linked to a large number of factors like economics and performance, safety and reliability, market regulations, environmental issues, or grid connection standards. KEPCO, a government company in Korea, has performed the project to identify and evaluate the performance of Micro Gas Turbine(MGT) technologies focused on 30, 60kW-class grid-connected optimization and combined Heat & Power performance. This paper describes the results for the mechanical, electrical, and environmental tests of MGT on actual grid-connection under Korean regulations. As one of the achievements, the simulation model of Exhaust-gas Absorption Chiller was developed, so that it will be able to analyze or propose new distributed generation system using MGT. In addition, KEPCO carried out the field testing of the MGT Cogeneration system at the R&D Center Building, KEPCO. The field test was conducted in order to respond to a wide variety of needs for heat recovery and utilization. The suggested method and experience for the evaluation of the distributed generation will be used for the introduction of other distributed generation technologies into the grid in the future.

• 마이크로전자및패키징학회지
• /
• 제22권1호
• /
• pp.7-14
• /
• 2015

Recently, advances in nano-material researches have opened the door for various transparent conductive materials, which include carbon nanotube, graphene, Ag and Cu nanowire, and printable metal grids. Among them, Ag nanowires are particularly interesting to synthesize because bulk Ag exhibits the highest electrical conductivity among all metals. Here we reviewed recently-published research works introducing various devices from organic light emitting diode to tactile sensing devices, all of which are employing AgNW for a conducting material. They proposed methods to enhance the stretchability and reversibility of the transparent electrodes, and apply them to make various flexible and stretchable electronics. It is expected that Ag nanowires are applicable to a wide range of high-performance, low-cost, stretchable electronic devices.

• Advances in Energy Research
• /
• 제2권1호
• /
• pp.47-59
• /
• 2014

Back-to-back STATCOM configuration is an extension of STATCOM in which the reactive power at two-sides and the real power flow through the DC link can be controlled concurrently and independently. This flexible operation brings many advantages to the micro-grids, distributed generation based systems, and deregulated power systems. In this paper, the dynamic control characteristics of the back-to-back STATCOM is investigated by simulating the detailed converter-level model of the converters in PSCAD. Various case studies in a single-machine test system are studied to present that the real power control feature of the BtB-STATCOM, even with a simple controller design, can enhance the transient stability of the machine under different fault scenarios.

• 전기학회논문지
• /
• 제62권6호
• /
• pp.737-743
• /
• 2013

This paper describes the overvoltage through lightning surge analysis on underground system in DC combined distribution systems. It is considered that operating micro grid including distributed generation with smart grid can make possibility of composing new distribution system different from existing one. However, there are many papers about low voltage DC distribution in grids or buildings but not many about replacement or distributing 22.9kV AC distribution system to DC system. Among many research need for DC system development, overvoltage is studied in this paper. Overvoltage is simulated on DC cable when lightning strikes to overhead grounding wire which is installed at the nearest location from power cable section. Analysis as well as modeling is performed in EMTP/ATPDraw. It is evaluated that analysis results can be used to design of DC underground distribution power cable system.

• 정보처리학회논문지A
• /
• 제19A권2호
• /
• pp.85-92
• /
• 2012

본 논문에서는 다수의 고속 이동체들의 위치를 측정할 수 있는 확장성 있는 실시간 위치 측정 시스템을 제안한다. 제안된 시스템에서는 위치 서비스가 필요한 영역을 확장 시 기본 단위인 매크로셀이라고 불리는 정사각형의 격자들로 나누고, 한 매크로셀은 $N{\times}N$ 개의 마이크로셀로 나눈다. 마이크로셀의 각 꼭짓점에는 위치 기준 노드가 중앙에는 중재 노드가 설치된다. 위치를 측정하고자 하는 이동체는 우선 중재 노드와의 통신을 통하여 위치 측정을 위한 허가를 받아야 한다. 그러므로 한 마이크로셀내에서는 오직 허가된 하나의 이동 노드만이 위치 기준 노드들과 연속적으로 통신하면서 자신의 위치를 계산할 수 있다. 제안된 시스템의 성능을 측정하기 위하여, 제안된 시스템을 모델링하고 시뮬레이션 하였다. 시뮬레이션 결과 제안된 시스템은 위치 측정을 위한 통신 시간이 짧고 고속 이동체의 위치를 계산할 경우 오차가 적은 것으로 나타났다.

• 대한기계학회논문집A
• /
• 제26권8호
• /
• pp.1709-1718
• /
• 2002

It is well recognized that improving capacity of positive grid in battery is one of key factors for controlling the expected long lift-time of Battery Energy Storage System(B.E.S.S). Thus it is really important to characterized material properties of positive grid which are mainly affected by fabrication process. In this study, two kinds of positive grids, which were fabricated by gravity casting and die-casting technique were used. Micro-structural observation and tensile test were conducted to investigate the effect of fabrication process of positive grid. Ultrasonic measurement based on pulse-echo method and ultrasonic C-scan technique also performed to correlate ultrasonic velocity with porosity ratio in positive grid. It was found that the porosity ratio of grid fabricated by gravity casting technique increased significantly compared to the grid fabricated by die-casting technique. It was also shown that ulrasonic technique is effective to evaluate the porosity ratio in positive grid.