• 전기학회논문지
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• 제65권8호
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• pp.1334-1339
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• 2016

In a power grid that has a high wind power penetration, the fast voltage support of a wind power plant (WPP) during the grid fault is required to stabilize the grid voltage. This paper proposes a voltage control scheme of a doubly-fed induction generator (DFIG)-based WPP that can promptly support the voltage of the point of common coupling (PCC) of a WPP during the grid fault. In the proposed scheme, the WPP and DFIG controllers operate in a voltage control mode. The DFIG controller employs two control loops: a maximum voltage dip-dependent reactive current injection loop and a reactive power to voltage loop. The former injects the reactive power in proportion to the maximum voltage dip; the latter injects the reactive power in proportion to the available reactive power capability of a DFIG. The former improves the performance of the conventional voltage control scheme, which uses the latter only, by increasing the reactive power as a function of the maximum voltage dip. The performance of the proposed scheme was investigated for a 100-MW WPP consisting of 20 units of a 5-MW DFIG under various grid fault scenarios using an EMTP-RV simulator. The simulation results indicate that the proposed scheme promptly supports the PCC voltage during the fault under various fault conditions by increasing the reactive current with the maximum voltage dip.

• 설비공학논문집
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• 제23권2호
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• pp.164-171
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• 2011

The objectives of this study are to propose a suitable treatment facility for waste energy recovery after analyzing the waste generation and disposal situation in Jejudo, to establish the plan to install the solar photovoltaics and wind power plant considering the site conditions and finally to establish the environmental energy town plan in conjunction with the existing facilities. The food waste biogas plant is selected as the treatment capacity of 200 ton/day. It is estimated that the biogas plant will produce the electricity of 7,594 MWh per year, which will reduce the greenhouse gas of 4,177 $tCO_2$ per year. The solar photovoltaics and wind power plant will produce the electricity of 13,410 MWh per year, which will reduce the greenhouse gas of 7,375 $tCO_2$ per year. Environmental energy town will give us the reduction of operating cost by centralized treatment of residues and byproducts, and by efficient utilization of produced energy.

• 한국환경과학회지
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• 제28권2호
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• pp.219-224
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• 2019

In this study, we evaluated the energy production from plant-microbial fuel cells using representative indoor plants, such as Scindapsus aureus and Clatha minor. The maximum power density of microbial fuel cell (MFC) using S. aureus ($3.36mW/m^2$) was about 2 times higher than that of the MFC using C. minor ($1.43mW/m^2$). It was confirmed that energy recovery is possible using plant-MFCs without fuel. However, further research is needed to improve the performance of plant-MFCs. Nevertheless, plant-MFCs have proved their potential as a novel energy source to overcome the limitations of the conventional renewable energy sources such as wind power and solar cells, and could be employed to a power source for the sensor in charge of the fourth industrial revolution.

• 한국산학기술학회논문지
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• 제16권4호
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• pp.2737-2743
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• 2015

풍력발전은 풍력단지가 전력계통과 접속되는 모선의 전압을 유지 또는 제어하기 위한 충분한 무효전력을 공급할 수 있어야 한다. 하지만 풍력단지와 계통 접속점(POI - Point of Interconnection) 모선을 연결하는 선로의 무효전력 손실 때문에 풍력터빈의 무효전력공급은 접속점의 전압을 제어하기에는 불충분하다. 이 문제는 접속점에 STATCOM(Static Synchronous Compensator)과 같은 부수적인 무효전력 보상장치를 설치하여 해결할 수 있다. 본 논문에서 제시하는 STATCOM과 Switched-Shunt, 탭변환 변압기와 같은 기존의 무효전력 보상장치의 협조제어를 사용하면 더욱 효과적으로 접속점 모선의 전압을 제어할 수 있다. 본 논문에서 제시한 방법을 이용하여 초기부하에 대하여 임의의 부하 변동률을 가지는 모의 시스템에 적용한 결과 접속점 모선의 전압강하는 60%이상 개선되었고 부하 모선의 전압은 정격전압의 95%이상을 유지하였다.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.672-675
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• 2007

Experimental data are presented which describe heat losses of cavity type receiver in wind tunnel. Experiments are conducted at various conditions such as the heater temperature in cavity changes from 300, 400, and 500 oC, wind speed in tunnel from 2 to 8 m/s, and four different tilt angle of 30, 50, 70, 90o. The power consumption including temperature, voltage and current for each experimental conditions are measured and stored in data logger at everyone second interval. The experimental results show that heat losses increase with increasing wind speed and with tilt angle. However, heat losses for the tilt angle of 70 and 90o is almost same at each heater temperature. In addition, the effects of natural convection in combined convection heat losses vary in according to the tilt angle.

• 한국전자통신학회논문지
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• 제13권3호
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• pp.547-554
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• 2018

풍력에너지는 청정 및 재생에너지의 가장 저렴한 모형중의 하나로 널리 알려져 있다. 실제로 몇몇 국가에서는 풍력에너지가 새롭게 건설되는 발전소들 중에서 화석연료 발전단가와 동등한 수준으로 만들어 오고 있다. 해상풍력 에너지 개발은 한국정부의 3020계획 목표달성을 위한 중요한 국내 에너지자원일 것으로 보인다. 풍력프로젝트의 개발단계 중에서 중심이 되는 항목은 풍력자원 평가이다. 풍력자원평가의 기본적인 3가지 등급 또는 단계는 예비부지확정, 부지 풍력자원 평가, 마이크로사이팅 등으로 나누어 분류할 수 있다. 본 연구에서는 6개소 해상기상탑 자료를 기반으로 3단계를 적용하여 전남 해상지역의 풍력발전 용량을 추정하는 것이다. 풍력프로젝트 개발을 위하여 소프트웨어 도구로 25년 이상 실적이 있고 풍력에너지 프로젝트 개발프로그램으로 잘 알려진 WindPRO를 사용하였다. 전남지역 해상풍력발전용량의 설계결과는 6개 풍력단지에서 총 2.52GW로 계산되었다.

• 전기학회논문지P
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• 제66권4호
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• pp.158-162
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• 2017

This paper did basic study on the vertical-axis wind turbine. Namely, This paper was try to find the optimum conditions by using the ANSYS CFX simulation program through the changes of the main-blade angle and sub-blade angle. Main-blade Shape #4 angle $45^{\circ}$ compared to others Shape angle $0^{\circ}$ was increased by 157.2[%] to 263.2[%] in the power output and was increased by 110[%] to 250[%] in the power coefficient. Also, when the Shape #5 Fin length of main-blade doubles, because the power output was 70.8[%] compared to Shape #1 and 27.5[%] compared to Shape #4, and the power coefficient was 60[%] compared to Shape #1 and 28.6[%] compared to Shape #4, the power output and the power efficiency were rather reduced. The output current of Shape #4 was increased 109.9[%] compared to Shape #1 and increased 250[%] compared to Shape #5, and The output voltage of Shape #4 was increased 22.5[%] compared to Shape #1 and increased 3.7[%] compared to Shape #4.

• 한국해안·해양공학회논문집
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• 제30권4호
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• pp.191-199
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• 2018

본 연구에서는 한국 연안의 해상풍력 발전을 위한 적지를 검토하기 위해 기상청에서 제공하는 20개 지점의 풍속 자료를 수집하고 이를 분석하였다. 관측된 풍속 자료의 분석을 위하여 Rayleigh 모델과 Weibull 모델을 이용하였으며, 풍속 출현빈도에 따라 연간 부존량을 추정하였다. 풍력발전기 모델로는 출력 1.5~5 MW의 7종류를 선정하여 각각의 성능곡선을 이용하였다. 그 결과, 풍속이 7.15 m/s 이상인 지점에서는 Repower-5 MW의 터빈이 높은 에너지 생산이 가능한 것으로 나타났으나 그 이하의 풍속에서는 G128-4.5 MW의 터빈이 유리한 것으로 나타났다. 10 m/s 이상의 풍속 출현율이 높은 마라도, 거제도 및 포항의 경우 REpower사의 5 MW급 해상풍력발전기 설치 시 설비이용률이 56.49%, 50.92%, 50.08%로 높게 나타났다.

• 조명전기설비학회논문지
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• 제26권9호
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• pp.64-72
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• 2012

The interest in wind power generation area such as developing and operating wind-diesel pilot complex in remote and island regions that have difficulty in having power plant and connecting to power system is growing rapidly in the world. We have installed and researched the hybrid system in Sekgok Pilot Complex to meet the new generation system. From the monitored data of the system, the performance of each diesel power plant is outstanding. However, step out problem was detected with respect to load sharing and synchronization with decentralized power supply. An advanced controller design having better response time and stability is needed to solve such problem. In this paper, we proposed the algorithm, through digital controller of Governor, which is applied to hybrid system. As a result, we obtained the stable frequency value in variable loading conditions. Also, we proved the advanced response time and stability through the simulation and experiment by applying additional current signal to the control algorithm.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2015년도 제46회 하계학술대회
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• pp.1094-1095
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• 2015

The costs of installation, loss, and energy not supplied energy for submarine cable of offshore wind power plant (OWPP) are very high because the level of technology is still in the early stage as well as because of the marine environments. Therefore, reducing the total costs of a grid network for OWPPs is very important for financial feasibility. In particular, it is needed to minimize the project cost for optimizing the grid design and offshore substation location of a OWPP. The suggested method can reduce the total system cost and make it lower compared with existing methods.