• 한국전자통신학회논문지
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• 제13권6호
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• pp.1229-1234
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• 2018

본 논문에서는 풍력발전기 너셀 내부에서 발생 가능한 화재를 예방하거나 신속하게 대응하기 위하여 광대역 전력선통신시스템 기반 화재 예방시스템을 구현하고 실증실험을 수행한 결과를 제시한다. 이를 위하여 고속 전력선통신용 주파수 대역에서 우수한 손실 특성을 가지는 유도성 통신 연결장치도 제작하였다. 구현된 시스템은 터빈 너셀에 설치된 온도, 불꽃, 연기센서 등 다양한 센서 정보와 열화상 이미지를 전력선통신시스템을 통하여 지상관제소에 고속 전송함으로써 너셀 내부의 환경변화를 실시간으로 감시할 수 있음을 확인하였다. 따라서 구현된 시스템은 이미 설치된 기존 안전시스템과 연동하여 풍력발전기 화재감시 및 예방체계의 신뢰성을 크게 향상시킬 수 있을 것으로 기대된다.

• 한국지능시스템학회논문지
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• 제23권1호
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• pp.1-6
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• 2013

정격풍속이상에서 발전기의 출력을 일정하게 유지하기 위하여 PID에 기초한 다양한 종류의 방법들이 발표되었다. 그러나 고정된 PID 이득을 이용한 이러한 방법에서는 전 영역에서 동작하리라는 보장이 없다. 이 논문에서는 전 영역에서 동작하는 시스템을 설계하기 위하여 풍속의 강도에 따라 PID 이득이 변하는 방법을 제안하였다. 풍속의 강도에 따라 피치각에 따른 전력의 민감도는 계속 변하는데, PID 이득을 민감도의 함수로 유도하였다.

• Journal of Electrical Engineering and Technology
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• 제9권3호
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• pp.835-842
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• 2014

Cutback control in a grid code is one of the functions of a wind power plant (WPP) that is required to support the system protection and frequency stability. When a cutback control command signal is delivered to the WPP from the system operator, the output of a WPP should be decreased to 20% of the rated power within 5 s. In this paper, we propose a dedicated cutback control algorithm of a WPP based on the ratio of the command power to the available power. If a cutback control signal is delivered, the algorithm determines the pitch angle for the cutback control and starts the pitch angle control. The proposed algorithm keeps the rotor speed at the speed before the start of the cutback control to quickly recover the previous output prior to the cutback control. The performance of the algorithm was validated for a 100 MW aggregated WPP based on a permanent magnet synchronous generator under various wind conditions using an EMTP-RV simulator. The results clearly shows that the proposed algorithm not only successfully reduces the output to the command power within 5 s by minimizing the fluctuation of the pitch angle, but also rapidly recovers to the output level before the cutback control.

• 한국생산제조학회지
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• 제22권2호
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• pp.216-222
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• 2013

A solar power generator is usually installed outdoors and it is exposed to extreme environments such as heavy fall of snow and high speed wind. Therefore, the solar tracker structure should be designed to have sufficient static and dynamic stiffness against such environmental conditions. In this paper, eigenvalue analysis of the solar tracker is carried out by varying the pose of the solar panel and unsteady flow analysis around a single tracker or multi-trackers arranged in a line is performed by varying the parameters such as wind directions, wind speeds and the pose of the solar panel to evaluate whether there exists an instability of resonance due to vortex shedding. Finite element eigenvalue analysis shows that natural frequencies and modes are almost not influenced by the pose of the solar panel and the finite element flow analysis shows that there does not exist periodic vortex shedding due to the flow around single tracker or multiple solar trackers in a line.

• 한국태양에너지학회 논문집
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• 제23권2호
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• pp.21-34
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• 2003

This study aims to present the applicability of wind turbine generator system to urban buildings for the utilization of clean renewable energy. The results are as follows; According to the wind resource analysis, it has been found that small sized wind power system can be viable for buildings application due to the amplification of wind velocity around buildings or building clusters, in spite of low mean velocity of 2-3m/s in Seoul and Kyunggi urban areas. But planners must perform micrositing analysis around building so that wind turbine can be located at high velocity zones. The system must be designed to avoid obstacles preventing prevailing wind in buildings. It should be recognized that wind speeds are changing depending on the height and length from buildings. The wind power system can be used as a symbol of landmark which shows a sustainable architecture from the scenary Itself A case study for apartment building in urban showed that wind power systems can be applicable in two kinds of place, rooftops and ground levels. Especially, the wind power systems must be carefully positioned so that wind resources do not decrease when it is installed at ground levels. and according to life cycle cost analysis, adaption of new small win4 power systems to buildings were proved to produce a profit if it is considered the expense of environment improvement and the wind speed increasing according to rise of building height. This research will ultimately achieve green architecture that preserves nature and at the same time provides pleasant environment to humans, and will play a great role in establishing the environment-preserving sustainable architecture of the 21th century.

• Journal of Electrical Engineering and Technology
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• 제5권3호
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• pp.371-378
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• 2010

Most modern wind turbines employ a doubly-fed induction generator (DFIG) system due to its many advantages, such as variable speed operation, relatively high efficiency, and small converter size. The DFIG system uses a wound rotor induction machine so that the magnetizing current of the generator can be fed from both the stator and the rotor. We propose a protection algorithm for a DFIG based on a d-q equivalent circuit in the time domain. In the DFIG, the voltages and currents of the rotor side and the stator side are available. The proposed algorithm estimates the instantaneous induced voltages of magnetizing inductance using those voltages and currents from both the stator and the rotor sides. If the difference between the two estimated induced voltages exceeds the threshold, the proposed algorithm detects an internal fault. The performance of the proposed algorithm is verified under various operating and fault conditions using a PSCAD/EMTDC simulator.

• 환경영향평가
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• 제32권5호
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• pp.279-290
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• 2023

최근 신재생에너지로서 바람의 힘을 이용한 풍력발전단지가 전국에 설치되면서 소음 문제가 대두되고 있다. 환경영향평가 및 사후환경영향평가에서도 풍력발전단지에 대한 배경소음 및 저주파소음을 측정하도록 하고 있으며, 특히 저주파소음은 환경부에서 2018년 공표한 저주파소음 관리 가이드라인에 따라 생활소음 측정방법을 준용하여 측정하도록 규정하고 있다. 고풍속에서 큰 소음을 발생시키는 풍력발전기의 특성상 고풍속에서 소음 측정이 이루어져야 하나 풍속이 증가할 경우 풍잡음이 증가하여 생활소음 및 저주파소음이 제대로 평가되지 못하는 문제가 발생되었다. 따라서 풍력발전기에서 발생되는 소음의 종류를 확인하고 풍잡음 등 풍력소음 측정시 고려되어야 할 사항을 확인하였다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1071-1072
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• 2011

The axial flux machine has higher power density than conventional radial flux machine, so it is widely applied to various industrial area, for instance, low speed wind power generator. For the conventional radial flux machine, 2D finite element method (FEM) is generally applied, but axial flux machine has to employ 3D FEM with long analysis time due to its own structural characteristic. This paper deals with the performance comparison of axial flux machine according to volume.

• 대한기계학회논문집B
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• 제33권8호
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• pp.565-572
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• 2009

In this research, a heater using eddy current for generator is designed and some analysis is performed to validate the system. FEM (finite element method) is used for analysing eddy current phenomena at the various speed of rotor with permanent magnet. A real heater system is fabricated. Some experiment is also performed to validate the analysis result. Through the experiment, the FE analysis is validated and we found that the efficiency of developed heater is over 94%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.23-24
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• 2007

Most of modern wind turbines employs a doubly-fed induction generator (DFIG) system because it has many advantages due to variable-speed operation, relatively high efficiency and it small converter size. The DFIG system uses a wound rotor induction machine so that the magnetizing current of the generator can be fed from both the stator and the rotor. This paper presents a protection relaying algorism for DFIG using the DQ equivalent circuits. The induced voltages calculated from the stator and rotor sides are nearly the same in the steady state. They become different in the DQ equivalent circuits during an internal fault. The proposed algorithm compares the inducted voltages estimated from the stator and the rotor circuit converted into the stationary reference frame. If the difference between the induced voltages exceeds the threshold, the proposed algorithm detects an turn-to-turn fault.