• KEPCO Journal on Electric Power and Energy
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• 제1권1호
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• pp.73-77
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• 2015

Offshore wind farms extend a distance from an onshore grid to increase their generating power, but long distance and high power transmissions raise a lot of cost challenges. LFAC (Low Frequency AC) transmission is a new promising technology in high power and low cost power transmission fields against HVDC (High Voltage DC) and HVAC (High Voltage AC) transmissions. This paper presents an economic comparison of LFAC and HVDC transmissions for large offshore wind farms. The economic assessments of two different transmission technologies are analyzed and compared in terms of wind farm capacities (600 MW and 900 MW) and distances (from 25 km to 100 km) from the onshore grid. Based on this comparison, the economic feasibility of LFAC is verified as a most economical solution for remote offshore wind farms.

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 2002년도 추계학술발표회요약집
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• pp.240-240
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• 2002

• Journal of Electrical Engineering and Technology
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• 제12권2호
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• pp.522-532
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• 2017

In this study, we propose a fault analysis method for a power distribution grid with PCS-based DERs. We first explain the characteristics of a PCS-based DER. According to the characteristics, the DER is considered as a current-controlled voltage source, which produces varying voltages within a certain limit so that currents equal to given references flowing from the DER to the grid (currents controlled). So, we introduce the symmetrical equivalent models in the form of varying voltage source for fault analysis and then, construct a convex optimization problem to solve the fault problem associated with the equivalent models and grid conditions. Thus, the proposed method enables to perform a proper fault analysis considering the characteristics of the DER, which are currents controlled, voltage limited, and unity power factor achievement. To verify the validity of the proposed method, we perform computer simulations with the proposed method and with MATLAB Simulink, and the results are compared.

• 전기학회논문지P
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• 제66권4호
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• pp.169-176
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• 2017

This paper presents research on low-voltage microgrids to maintain a continuous power supply to critical loads on grid-connected islands in Korea. The low-voltage microgrids of this paper focused on that changes public office buildings into uninterrupted microgrids by autonomous operation. For this, a microgrid controller (MGC) and a power conditioning system (PCS) that allow a seamless transfer between grid-connected and grid-isolated operation are proposed. The proposed PCS operates with a silicon controlled rectifier (SCR) switch and employs a simple structure. It supplies power continuously without operators through a coordinated operation between MGC and PCS. In addition, proposed MG has a schedule operation for minimizing electricity charges and provides ancillary services that enable the utilization of resources according to the operation purpose of utility distribution networks. To demonstrate the uninterrupted low-voltage microgrid proposed in this study, a microgrid was implemented and tested in a public office building in Anjwa Island, Jeollanam-do in Korea. A seamless, autonomous operation history, despite system disturbances, was obtained through a long-term demonstration of operation. The results showed that the proposed microgrid technology can be used to achieve energy resilience in grid-connected island areas.

• 전기학회논문지
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• 제62권10호
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• pp.1368-1375
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• 2013

The Smart Grid, which can monitor or diagnose the power grid in real time to operate efficiently, has been pushed ahead systematically as one of alternatives to solve these issues by combining the advanced Information Communication Technology and the electrical network. Hence, the electric company which introduces smart grid technology can read remotely the electrical meter readings by means of two-way communication between the meter and the central system. This enabled the customer and the utility to take part in reasonable electrical energy utilization. AMI became one of the core foundations in realizing the Smart Grid. It is hard to test the entire process of AMI system before the full deployment because it covers the broad objects from the customer to the utility operation system and requires mass data handling and management. Therefore, we design an efficient AMI network model and a simulator for performance evaluation required to simulate the network model similar to the real environment. This tool supports to evaluate the efficiency of the AMI network equipments and deployment. Additionally, it estimates the appropriate number of deployments and the proper capabilities.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.422-423
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• 2011

최근 들어 지구환경 변화에 따라 저탄소 녹색성장에 대한 요구가 증가하면서 스마트그리드 기반의 에너지 효율적 운영을 위한 연구가 활발히 진행되고 있다. 본 연구에서는 스마트그리드 환경에서 수용가의 전력수요를 효과적으로 모니터링하고 상시수요관리를 위한 제어가 가능하도록 하는 AMI(Automatic Metering Infrastructure) 시스템을 구현하기 위한 네트워크 개발 방법에 대한 연구내용을 소개하고자 한다.

• 한국태양에너지학회 논문집
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• 제28권5호
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• pp.72-77
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• 2008

The purpose of this paper is to explain the real characteristics of generation system of large scale power system of high voltage the grid connected PV power system for electricity industry. Main system is made up PCS in the class 150kVA. and we studied commercial operation in Korea-Western Power Company,(Tae-An headquarter) with the capacity of module is 122.5 $kW_p$. On the average, power plant utilities' utilization is 12.71 percent and consumption rate is 6.66 percent. We operated normally since 25th, August 2005 without any other problems.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.543-544
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• 2007

Micro-grid consists of micro-sources which adopt environmentally friendly and reliable power sources with independent real and reactive power control capability for providing premium power quality. This paper presents dynamic modeling and the stable operating range of the micro-grid system varying the parameters of the micro-sources. Case study results show the parameters affecting the stability of the micro-grid and the stable operating range of the micro-sources.

• Journal of Advanced Marine Engineering and Technology
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• 제38권4호
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• pp.403-408
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• 2014

조선소에서 건조하고 있는 선박, 해양플랜트에 설치된 발전기의 부하 성능 시험 시 생산되는 막대한 양의 전력은 컨테이너 형태로 제작된 로드뱅크를 통해 전량 열로 낭비된다. 따라서 본 연구에서는 선박 건조 시 발전기 부하시험으로 낭비되는 전력량을 대형 조선소를 대상으로 정량적으로 조사하였으며, 소형발전기에서 생산된 전력을 한전계통에 연계하여 회수하는 실험실의 실험결과를 바탕으로 조선소에서 발전기 부하시험 시 생산되는 전력을 한전계통에 연결할 경우 회수 가능한 전력량을 연구 분석하였다.

• 한국초전도ㆍ저온공학회논문지
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• 제12권3호
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• pp.29-33
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• 2010

For last 10 years, there are big progress and many efforts in the development of HTS power equipments by some country including South Korea. Especially HTS cable system is the strongest candidate among them from the viewpoint of applying to real grid, because of the feature of it, compact and large capacity. In South Korea, transmission level 154kV, the world top voltage class, HTS cable system was installed and has been tested in KEPCO Gochang Underground Cable Test Field since the early of 2010 in order to meet test requirements made by KEPCO, the only grid company in South Korea. The type test of it will be completed by October 2010 and subsequently long-term load cycle test will be performed during 6 months. Also in the near future, KEPCO has a plan to demonstrate transmission level HTS cable system in real grid, in order to meet practical requirements and confirm the feasibility of it. This paper says the test plan of transmission level 154kV HTS cable system and the way how to test it.