• 한국정보기술학회 영문논문지
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• 제10권2호
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• pp.91-101
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• 2020

Recently, the demand for high penetration of variable renewable energy (VRE) penetration in a power system is increased. In consequence, distribution systems including microgrids confront the increased installation of VRE-based distributed generation. Despite of the high demand of VRE-based distributed generation in a distribution system, the installation of photovoltaic (PV) system in a distribution system has been restricted by various problems. In other words, the hosting capacity for high VRE penetration in a distribution system is limited. This paper analyzes the improvements of hosting capacity VRE penetration of stand-alone microgrid (SAMG) with energy storage system (ESS) by considering virtual-slack (VS) control based on power sensitivity. With the pre-defined power sensitivity, the ESS operates as virtual slack in the SAMG by controlling its bus voltage and phase angle indirectly. Therefore, the ESS enables the increase of VRE penetration in the SAMG. The proposed VS control is realized by analyzing the ESS as a virtual slack in power flow analysis based on power sensitivity. Then its validity is demonstrated with the case study on the SAMG in South Korea with practical data.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.271-272
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• 2010

• 대한토목학회논문집
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• 제32권4D호
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• pp.305-311
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• 2012

단차로 무인 자동통행료 징수시스템(하이패스) 이용률증가와 함께 차단차로 운영, 차단기 작동 등에 따라 단차로 무인 자동통행료 징수시스템 차로 정체는 필연적이다. 이를 개선하기 위해 단차로 무인 자동통행료 징수시스템 차로 용량을 개선하기 위한 많은 연구가 진행 중이며, 대표적으로 스마트하이웨이사업에서 다차로 기반의 무정차 영업시스템(스마트톨링)을 들 수 있다. 본 고는 이러한 시스템의 효율성 개선으로써 스마트톨링의 용량증대 정도를 판단하고자 하였다. 이를 위해 기존 단차로 무인 자동통행료 징수시스템 자료를 바탕으로 스마트톨링시스템의 용량을 추정하는 방법을 제시하였다. 먼저, 단차로 무인 자동통행료 징수시스템 자료를 이용하여 포화차두시간을 산출한다. 그 다음으로 단차로 무인 자동통행료 징수시스템 차로의 용량을 산출한 다음, 단차로에서 다차로로 변경됨에 따라 바뀌는 주변도로환경을 계수화(양측장애물단측장애물 차로폭 및 측방여유폭 보정계수 증가분, 차단기 운영미운영 함에 따라 증가하는 용량 증가분, 차로폭 증가에 따른 용량 증가분)하고 이를 적용하여 다차로 용량을 추정하였다. 그 결과 각각의 경우 용량은 2172~2187대/시로 나타났으며, 기존 문헌에서 제시하는 최대값보다 약 370대/시 정도 많으며, 포화차두시간은 기존 단차로 무인 자동통행료 징수시스템의 차두시간에서 0.5초 정도 단축되어 용량개선 효과가 있는 것으로 판단되었다. 일부 한계와 향후연구사항이 같이 논의되었다.

• 전기학회논문지
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• 제56권7호
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• pp.1199-1204
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• 2007

In a cost based pool market, the generation capacity can be used as strategic bids by generation companies (Gencos) with the cost functions open to the market. Competition using strategic capacities is modeled by Cournot and Perfect Competiton (PC) model, and transformed into two by two payoff matrix game with Gencos' decision variables of Cournot and PC model. The payoff matrices vary when capacity payments are given to Gencos in accordance with their capacity bids. Nash Equilibrium (NE) in the matrices also moves with capacity price changes. In order to maximize social welfare of the market, NE should locate in a certain position of the payoff matrices, which corresponds to a PC NE. A concept of a critical capacity price is proposed and calculated in this paper that is defined as a minimum capacity price leading to PC NE. The critical capacity price is verified to work as a tool for suppressing a strategic capacity withholding in simulations of a test system.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2010년도 춘계학술대회 초록집
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• pp.78.1-78.1
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• 2010

Recently, as much supplied with new-renewable energy, as much invested in PV system. PV system consists of PV module, PCS and Monitering system, and also could be classified into the type and the capacity by installation method and cost etc. When various systems are installed in the field, it is needed to research for applying in the field and establish infrastructure in order to ensure stable efficiency and reliability. In this study, as the basic design of the demonstration test facility, it is designed the basic PV systems for each capacity to test each PCS. In addition, It is drew the climatic conditions such as insolation, temperature and the design parameters such as installation angle, shades for the local demonstration project and expected the generation of each PV system.

• 한국초전도ㆍ저온공학회논문지
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• 제6권1호
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• pp.38-42
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• 2004

The cryogenic system for 6.6 kV/200 A inductive superconducting fault current limiter (SFCL) was developed at Yonsei university in 2003. The sub-cooled nitrogen cryogenic system could be applied to not only SFCL but also many other applied high-Tc superconducting (HTS) devices like superconducting motor, superconducting generator and superconducting magnetic energy storage (SMES). Generally, the cooling capacity of GM-cryocooler depends on the load temperature. Therefore it is necessary to perform the cooling capacity test at no load condition to calculate the exact cooling power and heat load of cryogenic system. In this research, the cooling capacity test of GM-cryocooler was executed and the heat load of developed cryogenic system was calculated. The long run operation test results of sub-cooled nitrogen cryogenic system were successful in pressure and temperature condition. Moreover, the design and fabrication method of cryogenic system were introduced and the test results were described.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.105-112
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• 1996

A practical approach for the assessment of system reliability-based safety and load carring capacity under vehicle traffics is proposed for the realistic evaluation of safety and rating of cable-stayed bridges. A partial event tree analysis model incorporating major critical failure paths is suggested as a practical tool for the system reliability analysis and system reliability-based capacity rating. The proposed approach for the system reliability analysis and system reliability-based rating is applied to the safety assessment of the Jindo Bridge which is one of two existing cable-stayed bridges in Korea. The results of analyses at the system level based on the system reliability are compared with those at the element level.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 추계학술대회 논문집
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• pp.697-700
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• 2007

Six thousands of vehicles are operated on Korean urban transit system. 95% of them have regeneration system. Especially, the VVVF-Inverter vehicle has a merit of the highest regeneration rate. Therefore, the energy storage system is needed to be developed to use regeneration energy when the vehicle is braking. Therefore, Measuring regeneration energy in the substation need to know how much regeneration energy occurs, how much capacity of energy storage system is needed. After measuring regeneration energy, we design the capacity of energy storage system.

• 한국통신학회논문지
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• 제28권10A호
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• pp.788-795
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• 2003

We analyze the performance of a truncated power controlled CDMA(code division multiple access) cellular systems with base station antenna arrays. Erlang capacity and the channel capacity which is a maximum date rate to maintain almost error free communication are analytically derived. The numerical results show there can be a substantial increase in Erlang capacity and in channel capacity by antenna arrays incorporating with the truncated power control scheme.

• 품질경영학회지
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• 제41권1호
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• pp.15-38
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• 2013

Purpose: This study is to search for the core factors of improving business performance of small and medium venture manufacturing company and to do an in-depth analysis of the relations with management performance through systematic approach and to provide implications of importance of the management for the improvement factors for the domestic small and medium venture manufacturing company. Methods: The data have been analyzed via the regression and path analysis using AMOS. Results: this study is absorptive capacity affects the business performance of manufacturing companies. absorptive capacity has the role of the parameters of the Quality Management System and business performance. Conclusion: This study suggests how to run absorptive capacity according to type of management performance, and how to enhance Quality Management System to efficiently promote absorptive capacity in order to grow of management performance. also, this study shows a way to enlarge the valuation standard for management and customer performance reflecting the growth potential of an enterprise in circumstance where the valuation standard focuses on financial performance.