• Title, Summary, Keyword: Wind speed

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An Estimation of Extreme Wind Speed of Typhoon Affecting the Damage of Public and Industrial Facilities (공공 및 산업시설 피해에 영향을 미치는 태풍의 최대풍속 도출)

  • Jung, Woo-Sik
    • Journal of Environmental Science International
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    • v.24 no.9
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    • pp.1199-1210
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    • 2015
  • There were 35 typhoons affecting Korean Peninsula from 1999 to 2009(The average annual number of typhoon is 3.18). Among these typhoons, the number of typhoon passing through the Yellow sea, the Southern sea and the East sea were 14, 6 and 15 respectively. Wind speed on the height of 10 m can be finally estimated using the surface roughness after we calculate wind speed on the height of 300 m from the data on the surface of 700 hPa. From the wind speeds on the height of 10 m, we can understand the regional distributions of strong wind speed are very different according to the typhoon tracks. Wind speed range showing the highest frequency is 10~20 m/s(45.69%), below 10 m/s(30.72%) and 20~30 m/s(17.31%) in high order. From the analysis of the wind speed on the hight of 80 m, we can know the number of occurrence of wind speed between 50 and 60 m/s that can affect wind power generation are 104(0.57%) and those of between 60 and 70 m/s that can be considered as extreme wind speed are even 8(0.04%).

An Estimation of Extreme Wind Speeds Using NCAR Reanalysis Data (NCAR 재해석 자료를 이용한 극한풍속 예측)

  • Kim, Byung-Min;Kim, Hyun-Gi;Kwon, Soon-Yeol;Yoo, Neung-Soo;Paek, In-Su
    • Journal of Industrial Technology
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    • v.35
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    • pp.95-102
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    • 2015
  • Two extreme wind speed prediction models, the EWM(Extreme wind speed model) in IEC61400-1 and the Gumbel method were compared in this study. The two models were used to predict extreme wind speeds of six different sites in Korea and the results were compared with long term wind data. The NCAR reanalysis data were used for inputs to two models. Various periods of input wind data were tried from 1 year to 50 years and the results were compared with the 50 year maximum wind speed of NCAR wind data. It was found that the EWM model underpredicted the extreme wind speed more than 5 % for two sites. Predictions from Gumbel method overpredicted the extreme wind speed or underpredicted it less than 5 % for all cases when the period of the input data is longer than 10 years. The period of the input wind data less than 3 years resulted in large prediction errors for Gumbel method. Predictions from the EWM model were not, however, much affected by the period of the input wind data.

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Nacelle-Mounted Lidar Beam Line of Sight (LOS) Wind Speed Calibration Procedure Using Meteorological Mast (기상탑을 이용한 나셀 거치형 라이다 빔의 LOS(Line of Sight) 풍속 교정절차)

  • Ryu, Dong-Hun;Lee, Min-Soo;Lim, Chae-Wook;Ko, Kyung-Nam;Shin, Dong-Heon;Kang, Bo-Sin;Kim, Dong-Wan
    • Journal of Wind Energy
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    • v.9 no.4
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    • pp.24-31
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    • 2018
  • Wind lidar application is increasing and its calibration method is required to use wind lidar as an alternative to the meteorological mast. A nacelle lidar calibration method is now being discussed in IEC 61400-50-3 (Wind energy generation systems - Part 50-3: Use of nacelle-mounted lidars for wind measurements), and the method is mainly based on the wind lidar beam line of sight (LOS) wind speed calibration suggested by DTU as DTU E-0020 (Calibrating Nacelle Lidars). In this paper, a LOS wind speed calibration method is introduced and a calibration example performed on Jeju island is presented. The results showed a slope of 1.011 and R2 of 0.997, which means that the LOS wind speed is highly correlated with the reference wind speed and is comparable. But LOS wind speed calibration requires a very long time due to its principle and environmental conditions, and a calibration method that can overcome this problem of uncontrollable environments needs to be developed.

Power Curve of a Wind Generator Suitable for a Low Wind Speed Site to Achieve a High Capacity Factor

  • Yoon, Gihwan;Lee, Hyewon;Lee, Sang Ho;Hur, Don;Cheol, Yong
    • Journal of Electrical Engineering and Technology
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    • v.9 no.3
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    • pp.820-826
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    • 2014
  • It is well known that energy generated by a wind generator (WG) depends on the wind resources at the installation site. In other words, a WG installed in a high wind speed area can produce more energy than that in a low wind speed area. However, a WG installed at a low wind site can produce a similar amount of energy to that produced by a WG installed at a high wind site if the WG is designed with a rated wind speed corresponding to the mean wind speed of the site. In this paper, we investigated the power curve of a WG suitable for Korea's southwestern coast with a low mean wind speed to achieve a high capacity factor (CF). We collected the power curves of the 11 WGs of the 6 WG manufacturers. The probability density function of the wind speed on Korea's southwestern coast was modeled using the Weibull distribution. The annual energy production by the WG was calculated and then the CFs of all of the WGs were estimated and compared. The results indicated that the WG installed on the Korea's southwestern coast could obtain a CF higher than 40 % if it was designed with the lower rated speed corresponding to the mean wind speed at the installation site.

Seasonal Mean Wind Direction and Wind Speed in a Greater Coasting Area (우리나라 근해구역의 계절별 평균 풍향$\cdot$풍속 고찰)

  • Seol Dong Il
    • Proceedings of KOSOMES biannual meeting
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    • pp.163-166
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    • 2003
  • The seasonal mean wind direction and wind speed in a greater coasting area are investigated using the ECMWF(European Centre for Medium-Range Weather Forecasts) data for 11 years from 1985 to 1995. In winter, the main wind direction in Korea and vicinity, Taiwan and vicinity, and the North Pacific Ocean of middle latitudes is a northwesterly wind, northeasterly wind, and westerly wind respectively. The wind speed is strongest in the East China Sea, the South China Sea, and the North Pacific Ocean of low latitudes(Beaufort wind scale 5-6). A distribution pattern of wind direction in spring and fall is similar to that in winter. Seasonal mean wind speed is strongest in winter and the next is fall. The wind speed in summer is generally weak. However, that in the Indochina and vicinity is strong by the influence of Asian monsoon.

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Estimation of Surface Wind Speed on the Strong Wind Damage by Typhoon (태풍으로 인한 강풍 피해 추정을 위한 지상풍 산정 연구(Ⅰ))

  • Park, Jong-Kil;Jung, Woo-Sik;Choi, Hyo-Jin
    • 한국방재학회:학술대회논문집
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    • pp.85-88
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    • 2008
  • Damage from typhoon disaster can be mitigated by grasping and dealing with the damage promptly for the regions in typhoon track. What is this work, a technique to analyzed dangerousness of typhoon should be presupposed. This study estimated 10m level wind speed using 700hPa wind by typhoon, referring to GPS dropwindsonde study of Franklin(2003). For 700hPa wind, 30km resolution data of Regional Data Assimilation Prediction System(RDAPS) were used. For roughness length in estimating wind of 10m level, landuse data of USGS are employed. For 10m level wind speed of Typhoon Rusa in 2002, we sampled AWS point of $7.4\sim30km$ distant from typhoon center and compare them with observational data. The results show that the 10m level wind speed is the estimation of maximum wind speed which can appear in surface by typhoon and it cannot be compared with general hourly observational data. Wind load on domestic buildings relies on probability distributions of extreme wind speed. Hence, calculated 10m level wind speed is useful for estimating the damage structure from typhoon.

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Experimental Assessment with Wind Turbine Emulator of Variable-Speed Wind Power Generation System using Boost Chopper Circuit of Permanent Magnet Synchronous Generator

  • Tammaruckwattana, Sirichai;Ohyama, Kazuhiro;Yue, Chenxin
    • Journal of Power Electronics
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    • v.15 no.1
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    • pp.246-255
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    • 2015
  • This paper presents experimental results and its assessment of a variable-speed wind power generation system (VSWPGS) using permanent magnet synchronous generator (PMSG) and boost chopper circuit (BCC). Experimental results are obtained by a test bench with a wind turbine emulator (WTE). WTE reproduces the behaviors of a windmill by using servo motor drives. The mechanical torque references to drive the servo motor are calculated from the windmill wing profile, wind velocity, and windmill rotational speed. VSWPGS using PMSG and BCC has three speed control modes for the level of wind velocity to control the rotational speed of the wind turbine. The control mode for low wind velocity regulates an armature current of generator with BCC. The control mode for middle wind velocity regulates a DC link voltage with a vector-controlled inverter. The control mode for high wind velocity regulates a pitch angle of the wind turbine with a pitch angle control system. The hybrid of three control modes extends the variable-speed range. BCC simplifies the maintenance of VSWPGS while improving reliability. In addition, VSWPGS using PMSG and BCC saves cost compared with VSWPGS using a PWM converter.

Technique for Measuring Wind Speed and Direction Using a Roll-rotating Three-Axis Ultrasonic Anemometer (롤 회전하는 3축 초음파 풍속계를 활용한 풍향 풍속 측정기법)

  • Chang, Byeong Hee;Lee, Seunghoon;Cho, Tae Hwan;Kim, Yang won
    • Journal of Wind Energy
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    • v.9 no.3
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    • pp.5-12
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    • 2018
  • A technique for measuring wind speed and direction by using a roll-rotating three-axis ultrasonic anemometer was proposed and verified by wind tunnel tests. The test conditions were chosen to cover the operational range of typical wind turbines. The results of measuring the roll-rotating three-axis ultrasonic anemometer were converted on a fixed-roll axis and compared with those of a non-rotating anemometer. As a result, the residual errors that remained after axis transform were within the anemometer accuracy except for an RMS error of wind speed at yaw $30^{\circ}C$. But at yaw $0^{\circ}C$, it was reduced within the anemometer accuracy. This roll-rotating measuring technique was successful regardless of rotating speed, wind speed, and sampling rate. In order to use this rotating measuring technique as a spinner anemometer for wind turbines, the effect of the spinner has to be considered Theoretically, the effect of the spinner amplifies the wind direction along the rotational axis and the measured flow direction is larger than the incoming wind direction. This trend seems to be favorable for yaw control if wind direction is measured during yaw motion and feedback to yaw control.

Voltage Impacts of a Variable Speed Wind Turbine on Distribution Networks

  • Kim, Seul-Ki;Kim, Eung-Sang
    • KIEE International Transactions on Power Engineering
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    • v.3A no.4
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    • pp.206-213
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    • 2003
  • The main purpose of this paper is to present a simulation model for assessing the impacts of a variable speed wind turbine (VSWT) on the distribution network and perform a simulation analysis of voltage profiles along the wind turbine installed feeder using the presented model. The modeled wind energy conversion system consists of a fixed pitch wind turbine, a synchronous generator, a rectifier and a voltage source inverter (VSI). Detailed study on the voltage impacts of a variable speed wind turbine is conducted in terms of steady state and dynamic behaviors. Various capacities and different modes of variable speed wind turbines are simulated and investigated. Case studies demonstrate how feeder voltages are influenced by capacity and control modes of wind turbines and changes in wind speed under different network conditions. Modeling and simulation analysis is based on PSCAD/EMTDC a software package.

An Efficient Method to Obtain Wind Speed Gradient with Low PRF Radar

  • 이종길
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.8 no.1
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    • pp.28-33
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    • 2004
  • The measurement of wind speed gradient is very important for the detection of hazardous wind shear conditions since they are characterized by the abrupt shift of wind velocity and direction. These weather conditions usually imply high wind speed which requires a high PRF radar for the measurement. However, the measurement of a large absolute wind velocity is not necessary to obtain wind speed gradient. In this paper, a method was proposed to obtain wind speed gradient with a simple low PRF radar which may be very useful for the purpose of practical applications.