• Journal of Environmental Science International
• /
• v.25 no.2
• /
• pp.247-257
• /
• 2016

To predict annual energy production (AEP) accurately in the wind farm where located in Seongsan, Jeju Island, Equivalent wind speed (EQ) which can consider vertical wind shear well than Hub height wind speed (HB) is calculated. AEP is produced by CFD model WindSim from National wind resource map. EQ shows a tendency to be underestimated about 2.7% (0.21 m/s) than HB. The difference becomes to be large at nighttime when wind shear is large. EQ can be also affected by atmospheric stability so that is classified by wind shear exponent (${\alpha}$). AEP is increased by 11% when atmosphere becomes to be stabilized (${\alpha}$ > 0.2) than it is convective (${\alpha}$ < 0.1). However, it is found that extreme wind shear (${\alpha}$ > 0.3) is hazardous for power generation. This results represent that AEP calculated by EQ can provide improved accuracy to short-term wind power forecast and wind resource assessment.

• Computational Structural Engineering
• /
• v.2 no.2
• /
• pp.62-72
• /
• 1989

This study presents rational methods for probability-based estimates of basic design wind speeds in Korea and proposes a risk-based nation-wide map of design wind speeds. The paper examines the fittings of the extreme Type I mode to largest yearly non-typhoon wind data from long-term records, and to largest monthly non-typhoon wind data from short-term records. For the estimation of the extreme typhoon wins speed distribution, an indirect analytical method based on a Monte-Carlo simulation is applied to typhoon-prone regions. The basic desig wind speeds for typhoon and non-typhoon winds at the sites of concern are made to be obtained from the mixed model given as a product of the two distributions. The results of this study show that the proposed models and methods provide a practicable tool for the development of the risk-based basic design wind speed and the design wind map from short-term station records currently available in Korea.

• Wind and Structures
• /
• v.15 no.2
• /
• pp.177-188
• /
• 2012

The meteorological events that cause most strong winds in Brazil are extra-tropical cyclones, downbursts and tornadoes. However, one hurricane formed off the coastline of southern Brazil in 2005, a tropical storm formed in 2010 and there are predictions that others may form again. Events such as those described in the paper and which have occurred before 1987, generate data for the wind map presented in the Brazilian wind loading code NBR-6123. This wind map presents the reference wind speeds based on 3-second gust wind speed at 10 m height in open terrain, with 50-year return period, varying from 30 m/s (north half of country) to 50 m/s (extreme south). There is not a separation of the type of climatological event which generated each registered velocity. Therefore, a thunderstorm (TS), an extra-tropical pressure system (EPS) or even a tropical cyclone (TC) are treated the same and its resulting velocities absorbed without differentiation. Since the flow fields generated by each type of meteorological event may be distinct, the indiscriminate combination of the highest wind velocities with aerodynamic coefficients from boundary layer wind tunnels may lead to erroneous loading in buildings.

• Journal of Wind Energy
• /
• v.14 no.3
• /
• pp.5-13
• /
• 2023

Floating LiDAR systems (FLSs) are used in many countries because they are easier to install than stationary weather towers, have low maintenance costs, and can be installed in deep sea areas. However, FLSs are rarely used in Korea due to a lack of clear evaluation criteria to verify the reliability and uncertainty of their measurements. This study is the first to verify the reliability of FLSs in Korea with one-year simultaneous observation of six lidar systems - two fixed and four floating systems - in sea areas of Gunsan and Yeonggwang. The reliability of FLSs measurement data was verified by comparison between fixed and floating systems. Moreover, differences between existing wind resource maps and the data observed from the six points were analyzed and wind resource maps were calibrated. The results show a return rate of more than 95 % of the observed data and strong correlations between fixed and floating systems (average R2 of 0.977). Additionally, errors in wind speed predictions to produce a wind resource map could be significantly reduced from 5.7 % to 0.6 % after calibrations with the observation data.

• Journal of the Korean Solar Energy Society
• /
• v.31 no.6
• /
• pp.8-22
• /
• 2011

Investigations on modeling methods of a CFD wind resource prediction program, WindSim for a ccurate predictions of wind speeds were performed with the field measurements. Meteorological Masts having heights of 40m and 50m were installed at two different sites in complex terrain. The wind speeds and direction were monitored from sensors installed on the masts and recorded for one year. Modeling parameters of WindSim input variables for accurate predictions of wind speeds were investigated by performing cross predictions of wind speeds at the masts using the measured data. Four parameters that most affect the wind speed prediction in WindSim including the size of a topographical map, cell sizes in x and y direction, height distribution factors, and the roughness lengths were studied to find out more suitable input parameters for better wind speed predictions. The parameters were then applied to WindSim to predict the wind speed of another location in complex terrain in Korea for validation. The predicted annual wind speeds were compared with the averaged measured data for one year from meteorological masts installed for this study, and the errors were within 6.9%. The results of the proposed practical study are believed to be very useful to give guidelines to wind engineers for more accurate prediction results and time-saving in predicting wind speed of complex terrain that will be used to predict annual energy production of a virtual wind farm in complex terrain.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.10 no.1
• /
• pp.9-14
• /
• 2010

Recent increase in the strength and frequency of typoons due to climate change claims reconsideration of the design wind load in existing design codes for civil engineering structures in which the basic wind speed is estimated based on meteorological data by mid 1990s. In this paper, based on wind speed data at 76 observatories in Korea from 1961 through 2008, the basic wind speeds which can be utilized in designing civil engineering structures including buildings and bridges are estimated using the statistical process. The return period of the wind speed for each location is determined using the Gumbel distribution. The results for considered locations are compared to the existing design codes. Also, for design applications, the wind speed map, which classifies the country into four basic wind speed zones, is proposed using the resulting basic wind speeds.

• Journal of the Korean Society of Hazard Mitigation
• /
• v.11 no.3
• /
• pp.1-8
• /
• 2011

In this study, a wind hazard map over Korea peninsula based on geographical information is developed, which consists of the surface roughness model, the topographical effect model and the homogeneous wind model. The surface roughness model is assessed to evaluate the effect of the surface roughness on the wind field near ground. The topographical effect model is assessed to quantify the effect of the speed-up caused by topology, which is calculated by adopting the topographical effect factor in Korea building code (2005). The homogeneous wind map is created either by a frequency analysis method for meteorological data or a typhoon simulation. The results show that the wind hazard map can be applied to the determination of insurance premium as well as the assessment of loss and damage.

• The Korean Journal of Applied Statistics
• /
• v.23 no.6
• /
• pp.1157-1167
• /
• 2010

This paper details a method for establishing a wind energy map having($1Km{\times}1Km$) resolution. The map is essential for measurement and efficiency-testing of wind energy resources and wind site analysis. To this end, a statistical wind field model is estimated that covers 345,682 regions obtained by $1Km{\times}1Km$ lattices made over South Korea. The paper derives various characteristics of a regional wind energy resource under the statistical wind field model and estimates them to construct the wind energy map. Kolmogorov-Smirnov test, based on TMY(typical meteorological year) wind data of 76 weather station areas, shows that a Log-normal model is adequate for the statistical wind field model. The model is estimated by using the wind speed data of 345,682 regions provided by the National Institute of Meteorological Research(NIMR). Various wind energy statistics are studied under the Log-normal wind field model. As an application, the wind energy density(W$/m^2$) map of South Korea is constructed with a resolution of $1Km{\times}1Km$ and its utility for the wind site analysis is discussed.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.05a
• /
• pp.324-326
• /
• 2008

When we urgently need to develop and supply an alternative energy, wind power is growing with much interest because it has relative low cost of power and area of tower. To estimate the wind power resource, it is necessary to make an wind resource map first. On the study of wind resource map in the Korean peninsula, Southern coast was needed to investigate the possibility of developing wind power complex because of good wind resources. In this study, we made a vertical observation to analyze the properties of wind in coastal area. From tethered sonde observation, we knew that synoptic effect had an influence higher in second day than first day. This means local wind circulation is generated on first day but not second day. The local wind made vertical wind shear strong in first day. Also, there was large difference of wind speed between layers at night time by analysis of SODAR observation.

• Journal of the Korean Association of Geographic Information Studies
• /
• v.16 no.3
• /
• pp.126-135
• /
• 2013

With more than 70% of the country consisting of mountains, Korea has large and small mountains, and hills located in the inner cities. Therefore, Korea's architectural structure laws stipulate that an increase in wind speed due to the influence of terrain should be considered in the design of wind loads of buildings. But if more than two mountains are located around the building or if the boundaries of the land surface are not clear when calculating topographic factors of wind speed, the designer has subjectively selected the coverage of the topographic factors of wind speed or the surface. This may lead to unscientific design of wind loads. This study attempts to analyze topographic factors of wind speed by using a 1:5000 topographic map with relatively high location accuracy and thereby to reflect changes due to the topographic characteristics and influence at the point where the building is located. By also selecting terrain surfaces and vertexes through Arc GIS and presenting a scientific approach to determine the range of topographic factors of wind speed, this study is expected to make a contribution for more rational and cost-effective wind-resistant design of buildings.