• Korean Journal of Remote Sensing
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• v.36 no.4
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• pp.557-571
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• 2020

High-resolution flows around a steep mountainous island (Ulleungdo) in Korea were simulated by a computational fluid dynamics (CFD) model. To cover entire Ulleungdo and to resolve the topography around the Ulleungdo automatic synoptic observing system (ASOS) with high resolution, one-way nested grid system with large (60 m), and small (20 m) grid sizes was applied in the CFD model simulations. We conducted the numerical simulations for 16 inflow directions, and, for each inflow direction, we considered six different wind velocities(5, 10, 15, 20, 25, and 30 m s^-1) at the reference height (1,000 m). The effects of topography on surface wind observations were well reflected in the observed wind roses for the period of January 01, 2012 ~ December 31, 2016 at the Ulleungdo ASOS and marine buoy. Wind roses at the Ulleungdo ASOS was reproduced based on the CFD simulations. The changes in surface winds at the Ulleungdo ASOS caused by surrounding topography were relatively well simulated by the CFD model. The simulated wind-rose indicated that south-southwesterly and northeasterly were the dominant wind directions, which were also observed at the Ulleungdo ASOS. We investigated the flow characteristics around the Ulleungdo ASOS for northwesterly, south-southwesterly, and northeasterly winds in detail.

• Proceedings of the KIPE Conference
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• 2008.06a
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• pp.82-84
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• 2008

This paper presents the modeling and power quality analysis of Jeju island power system connected with wind farm, and thermal power plant. It is for indicating the influence of wind farm operation in steady and transient state in Jeju island power system during the HVDC system overhaul period. For the computer simulation, three kinds of main item are modeled, which are 67[MW] wind farm, thermal power plant and Jeju power load. To analyze the influence of the wind power generation to the Jeju power system, two kinds of simulations are carried out by using the PSCAD/EMTDC program. One is the steady state operation under the variable speed wind, and the other is the transient state operation when all of wind farms in Jeju island are disconnected from the Jeju power grid instantaneously on the rated power output. With the comparison of these results, it is useful for analyzing the power quality of Jeju power system versus wind power generation.

• Journal of the Korean Solar Energy Society
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• v.33 no.6
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• pp.70-76
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• 2013

Recently industrial control systems have been required to ensure intelligent, high tech automation, interconnection and interoperability demands. Therefore, there is a need to redefine the structure concepts of SCADA system for wind power. Also, at this time, the integrated management system is required for the distributed development of wind farms where are needed often interoperability features and exchange information between different wind farms, wind turbines or SCADA systems. In this paper, an integrated structural concepts for SCADA system are defined. Based on this definition of an integrated SCADA system, the basic designs are analyzed on physical layer, system layer and application layer which are corresponded to wind turbine controller, the SCADA server and the SCADA client, and implement HMI. Between the implementation SCADA server and the client, their normal functions were verified at the small scale wind energy test facilities.

• Journal of Wind Energy
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• v.14 no.4
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• pp.13-20
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• 2023

A self-climbing crane (SCC) system is under development for the installation and maintenance of wind turbines. It can move vertically along the wind turbine tower by itself. One of the key components of the SCC system is the clamping pad to maintain a safe position on the wind turbine tower. The SCC system can maintain its position on the tower from the frictional force generated between the surfaces of the clamping pads and the tower. If the frictional force provided by the clamping pads are insufficient, the SCC system cannot stay in the vertical position on the tower. Therefore, the development of clamping pads with sufficient frictional force is very important for the SCC system. At the same time, the operation of the SCC system should not damage the paint coating of the wind turbine tower. In order to verify that the frictional force is sufficient and that frictional and compressive forces do not cause damage to the paint, a number of combined compression and shear loading tests were conducted using a test device prepared for this study. The details regarding the test specimens, test procedure, and test results are summarized in this paper.

• Wind and Structures
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• v.20 no.6
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• pp.739-749
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• 2015

Field measurement of wind characteristics is of great significance for the wind engineering community. High-frequency anemometers such as ultrasonic anemometers are widely used to obtain the high-frequency fluctuating wind speed time history. However, conventional instrumentation systems may suffer from low efficiency, non-real time transmission and higher maintenance cost, and thus are not very appropriate in the field measurement of strong winds in remote areas such as mountain valleys. In order to improve the field measurement performance in those remote areas, a wireless high-frequency anemometer instrumentation system for field measurement has been developed. In this paper, the architecture of the proposed instrumentation system, and measured data transmission and treatment will be presented firstly. Then a comparison among existing instrumentation systems and the proposed one is made. It shows that the newly-developed system has considerable advantages. Furthermore, the application of this system to the bridge site located in the mountain valley is discussed. Finally, typical samples of measured data from this area are presented. It can be expected that the proposed system has a great application potential in the wind field measurement for remote areas such as the mountainous or island or coastal area, and hazardous structures such as ultra-voltage transmission tower, due to its real-time transmission, low cost and no manual collection of data and convenience.

• Journal of Navigation and Port Research
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• v.35 no.5
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• pp.381-385
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• 2011

In this paper, an economic feasibility study of wind-diesel hybrid power systems for an island in the Yellow Sea, where the maximum power generation is about 500kW, was performed. For the study, annual electric load variation and wind resource data of the island were collected and analyzed. HOMER program - a typical hybrid optimization model for electric renewables including wind resource, developed by the National Renewable Energy Laboratory - was used. Wind speed and diesel price were picked out as variables for the sensitivity analysis in order to find the economic accountability for the wind-diesel hybrid power system. As the result, even though it is not feasible economically under the present condition, if mean wind speed is over 3 m/sec. or diesel price goes up to 2.4 $ per liter, the wind-diesel hybrid power system for the island becomes a prospective candidate.

• Wind and Structures
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• v.32 no.1
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• pp.55-69
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• 2021

Ultrapure ferritic stainless steel provides a new generation of long-span metal roof systems with continuous welding technology, which exhibits many unknown behaviors during wind excitation. This study focuses on the wind-resistant capacity of a new continuous welding stainless steel roof (CWSSR) system. Full-scale testing on the welding joints and the CWSSR system is performed under uniaxial tension and static ultimate wind uplift loadings, respectively. A finite element model is developed with mesh refinement optimization and is further validated with the testing results, which provides a reliable way of investigating the parameter effect on the wind-induced structural responses, namely, the width and thickness of the roof sheeting and welding height. Research results show that the CWSSR system has predominant wind-resistant performance and can bear an ultimate wind uplift loading of 10.4 kPa without observable failures. The welding joints achieve equivalent mechanical behaviors as those of base material is produced with the current of 65 A. Independent structural responses can be found for the roof sheeting of the CWSSR system, and the maximum displacement appears at the middle of the roof sheeting, while the maximum stress appears at the connection supports between the roof sheeting with a significant stress concentration effect. The responses of the CWSSR system are greatly influenced by the width and thickness of the roof sheeting but are less influenced by the welding height.

• Journal of Environmental Science International
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• v.19 no.6
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• pp.689-701
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• 2010

The effects of high-resolution wind profiler (HWP) data on the wind distributions were evaluated in two different coastal areas during the study period (23-26 August, 2007), indicating weak-gradient flows. The analysis was performed using the Weather Research and Forecasting (WRF) model coupled with a three-dimensional variational (3DVAR) data assimilation system. For the comparison purpose, two coastal regions were selected as: a southwestern coastal (SWC) region characterized by a complex shoreline and a eastern coastal (EC) region surrounding a simple coastline and high mountains. The influence of data assimilation using the HWP data on the wind distributions in the SWC region was moderately higher than that of the EC region. In comparison between the wind speed and direction in the two coastal areas, the application of the HWP data contributed to improvement of the wind direction distribution in the SWC region and the wind strength in the EC region, respectively. This study suggests that the application of the HWP data exerts a large impact on the change in wind distributions over the sea and thus can contribute to the solution to lack of satellite and buoy data with their observational uncertainty.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.327-330
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• 2008

This paper presents monitoring system for 750kW-class DFIG wind turbine generator system and an architecture for applying standardized communication, IEC61400-25. Monitoring and control system is consists of wind turbine PLC, Local and Remote I/O Server, HMI. and Web-server. Proposed System has been demonstrated in Daegi-ri, Kangwon-do, which aims to test local and/or remote monitoring and control system and evaluate the performance of 750kW-class WTS. Finally we described the design of logical nodes and services based on IEC61400-25 and its application scheme.

• Wind and Structures
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• v.8 no.3
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• pp.179-196
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• 2005

This paper describes the application of a wireless data acquisition system to monitor wind pressures and velocities with absolute pressure sensors and an anemometer. The system was developed for future deployment, as part of a research effort currently underway to instrument coastal homes in Florida to monitor roof wind pressures during hurricanes. The proposed wireless system will replace the current system that involves a large amount of hardwired connections from the sensors to the data processing unit that requires labor intensive wiring and preparation of the home. The paper describes comparison studies and field tests to assess the performance of the system. The new system offers the advantages of light hardware, ease of installation, capacity for 48 hours of continuous data acquisition, good frequency and amplitude responses, and a relatively simple maintenance. However, the tests also show that the shape of the shell that has been previously used to protect the sensors might interfere with the proper measurement of the pressures.