• 전기학회논문지
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• 제64권3호
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• pp.399-404
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• 2015

This paper presents the DC voltage control method in DC link of High Voltage Direct Current(HVDC) for an offshore wind farm in Low Voltage Ride Through(LVRT) situation. Wind generators in an offshore wind farm are connected to onshore network via HVDC transmission. Due to LVRT control of grid side inverter in HVDC, power imbalancing in DC link is generated and this consequentially causes rising of DC voltage. A de-loading scheme is one of the method to protect the wind power system DC link capacitors from over voltage. But the flaw of this method is slow control response time and that it needs long recovery time to pre-fault condition after fault clear. Thus, this paper proposes improved de-loading method and we analyze control performance for DC voltage in LVRT control of HVDC for an offshore wind farm.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제1권3호
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• pp.161-170
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• 2012

전 세계적으로 신재생에너지에 대한 관심이 고조되고 있다. 특히 풍력은 높은 경제성으로 인하여 연구개발이 활발히 진행되고 있다. 국내에 서도 서남해 지역에 대규모 해상 풍력발전단지 연구개발을 진행중에 있다. 현재 풍력발전단지 운영을 위한 SCADA 시스템의 국내 기술 수준은 매우 낮은 수준으로 대규모 발전단지에 적용이 가능한 SCADA 시스템 개발이 시급한 실정이다. 따라서 본 논문에서는 대규모 해상풍력발전단지 SCADA 시스템 개발을 위해서 필요한 고려 사항과 이를 바탕으로 SCADA 시스템 설계 내용을 기술하였다.

• Fisheries and Aquatic Sciences
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• 제24권11호
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• pp.341-350
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• 2021

The energy production of offshore wind farms plays an important role in expanding renewable energy. However, the development of offshore wind farms faces many challenges due to its incompatibility with marine environments and its social acceptability among the local community. In this study, we reviewed the marine environmental impact assessment status of offshore wind farm development projects for 2012-2019 in South Korea. A total of nine projects were selected for this study, all of which experienced considerable conflict with local fisheries resources. To appropriately respond to the underlying challenges faced by offshore wind farm development and in order to better support decision-making for future impact assessment, our findings identified: i) a need for adequate preliminary investigation and technical examination of fisheries resources; ii) a need to assess and estimate the impact of underwater noise, vibration, and electromagnetic waves on fisheries resources during wind farm construction and operation; and iii) a need for a bottom-up approach that allows for communication with local stakeholders and policy-makers to guarantee the local acceptability of the development.

• 전기학회논문지
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• 제57권11호
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• pp.1946-1953
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• 2008

Power system of Jeju is interconnected to the mainland using HVDC and that is also interconnected to three wind farms. It will be difficult to control of Jeju power system if HVDC is disconnected or HVDC is overhauled under large scale wind farms interconnected. We measured and analysed the power quality of two substation and two wind farms to assess that wind farms have an effect on Jeju system during the HVDC overhaul last May. We concentrated on the power quality like frequency, voltage variation, voltage harmonics, current harmonics, flicker. We can found that the frequency of Jeju system is very unstable during overhaul, so the frequency of Jeju system can be variated easily by wind farm's rapid output power variation. There are some benefits and weak points in power quality between two wind farms because each wind farm is consist of different wind turbines.

• 한국태양에너지학회 논문집
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• 제24권3호
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• pp.1-7
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• 2004

Using WAsP, which is PC-program for the vertical and horizontal extrapolation of wind data, annual energy production as well as wind energy density has been predicted for Haengwon wind farm in Jeju island. The predicted results were compared with real data derived from wind turbines in Haengwon wind farm. As the results, in order to produce more electric power, new wind turbines should be located along coastal line, which has comparatively high wind energy density. Also, the roughness length should be inputted to the Map Editor program for better agreement with real annual energy production.

• 동력기계공학회지
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• 제16권5호
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• pp.13-19
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• 2012

In this paper, the offshore wind farms have been designed by using WindPRO with the help of real wind data measurements at Jeju Costal area by calculating the annual energy production for exact economic evaluation. In order to achieve benefit of wind farm, the annual revenue for power generation have been calculated with SMP and REC value. And construction cost has derived from the real wind farm project case. Also O&M cost has been estimated by OMCE (Operating & Maintenance Cost Estimator) to get accurate cost of wind farm. Economic evaluation of wind farms have been performed by comparing above parameters. In addition, sensitivity analysis calculating the effect of these factors has also been carried out.

• 대한전기학회논문지:전력기술부문A
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• 제52권12호
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• pp.675-683
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• 2003

This paper describes the correction strategy of an overcurrent relay applied in the linked line for interconnecting wind farm with utility power networks in order to improve the capability of a fault detection. The fault current measured in a relaying point might vary according to the fault conditions. Generally, the current of the line to line fault or the line to ground fault in the linked line is much higher than the set value of protective relay due to the large fault level. However, when the high impedance fault occurs in the linked line, we can't detect it by conventional set value because its fault level may be lower than the generating capacity of wind farm. And, the protective relay with conventional set value may generate a trip signal for the insertion of wind turbine generators due to the large transient characteristics. In order to solve above problems and improve protective relaying algorithms applied in the linked line, we propose a new correction strategy of the protective relay in the linked line. The presented method can detect the high impedance fault which can't be detected by conventional relay set value and may prevent the mis-operation of protective relay caused by the insertion of wind farm.

• 조명전기설비학회논문지
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• 제29권2호
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• pp.97-103
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• 2015

This paper introduces two on-going projects for DC high temperature superconducting (HTS) cable systems in South Korea. This study proposes the application of DC HTS cable systems to enhance power transfer limits of a grid-connected offshore wind farm. In order to develop the superconducting DC transmission system model based on HTS power cables, the maximum transfer limits from offshore wind farm are estimated and the system marginal price (SMP) calculated through a Two-Step Power Transfer (TSPT) model based on PV analysis and DC-optimal power flow. The proposed TSPT model will be applied to 2022 KEPCO systems with offshore wind farms.

• 조명전기설비학회논문지
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• 제29권7호
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• pp.54-61
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• 2015

This paper presents short-term wind farm power forecasting method using multivariate analysis and time series. Based on factor analysis, the proposed method makes new independent variables which newly composed by raw independent variables such as wind speed, ramp rate, wind power. Newly created variables are used in the time series model for forecasting wind farm power. To demonstrate the improved accuracy, the proposed method is compared with persistence model commonly used as reference in wind power forecasting using data from Jeju Island. The results of case studies are presented to show the effectiveness of the proposed forecasting method.

• Journal of international Conference on Electrical Machines and Systems
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• 제2권1호
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• pp.104-110
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• 2013

In this paper an application of centralized pitch angle controller for fixed speed wind turbines based wind farm to mitigate load frequency fluctuation is presented. Reference signal for the pitch angle of each wind turbine is calculated by using proposed centralized control system based on wind speed information. The wind farm in the model system is connected to a multi machine power system which is composed of 4 synchronous generators and a load. Simulation analyses have been carried out to investigate the performance of the controller using real wind speed data. It is concluded that the load frequency of the system can be controlled smoothly.