To study wind characteristics in complex terrain, we installed three dimensional sonic anemometers at 67 m and 45 m above ground level in Iwaya wind park of Aomori prefecture in Japan. High resolution analysis of wind direction shows that the flow distortion arises along the undulating topography. Absolute values of vertical wind speeds observed at lower observation point are more or less larger than those at higher point, which is dependent on wind directions. The difference of vertical flow between different heights would relate to increase of the wind shear and the turbulent intensity. Due to such flow characteristics and large roughness on the ground, the turbulent intensity seems to be larger than IEC category A, in the wide range of wind direction keeping steep slope and complex topography.

風車タワートップフランジボルトにおける締付トルクと導入軸力の関係に関する研究

石原孟, 吉村豊, 剣持良章

公開日: 2017年10月03日

p.A_13-A_18

In this study, the relationship between tightening torque and axial force of bolt at the tower top flange was investigated through a laboratory test with flange section models and a 750 kW wind turbine which had experienced the damages of bolt at the tower top flange. Tightening torques and axial forces of bolt in these tests were measured directly by using torque wrenches and strain gauges inserted in the bolts. Existence of lubricant had a great influence on the axial force of bolt, while types of torque wrench had a small impact on those. The expected axial force of bolt was obtained by torque wrenches and the variation was around 10%. A method for quantitatively evaluating decrease in axial force of bolt was proposed by measuring rotation of bolt. The damaged bolts in the wind turbine were also investigated and the axial forces at the damaged bolts were completely lost, while those at the loosed bolts were more than 30% of the initial value. It was found that the axial force of bolt decreased by about 20% after 500 hours from the exchange of bolts. This indicates that retightening is necessary for wind turbine tower bolts.

各種物理量測定による風車ブレードの異常被雷検知システムの検討

藤本修平, 山根健次

公開日: 2017年10月03日

p.A_19-A_25

We conducted feasibility study of detection system for unexpected lightning damage for wind turbine blade. In this study, puncture of blade skin and disconnection of down conductor are considered as the lightning damage. Aimed at detect these damages, three systems are examined. The first system consists of two down conductors and current measuring devices that installed at root part of the conductors. The first system is appropriate to detection of puncture of blade skin caused by lightning strike of wintertime thunderbolt. The second system consists of two down conductors and optical fiber current sensors which are installed at tip and root of each conductors. The second system has the merits of enable to simple judgement system for lightning damage and periodic inspection (to confirm the soundness of the down conductors). The third system is based on acceleration measurement by sensors that installed at the blade skin. The acceleration sensors measure the elastic wave caused by lightning strike (puncture of the blade skin). Feasibility of the third system was confirmed by model experiment. The third system can be retrofit to an existing wind turbine blade.

風車タワーのL 型フランジにおける作用点修正係数の提案

飛永育男, 石原孟

公開日: 2017年10月03日

p.A_26-A_33

L-type flanges used for wind turbine towers need high bearing resistance when they install in storm and earthquake active areas. Petersen, Seidel, and RISO/DNV introduced methods for evaluation of L-type flange ultimate strength based on elastoplastic theory, however they didn’t consider the elastic deformation of flange and caused underestimation of the load acting on bolts. VDI2330, Petersen, and Seidel also showed the location of equivalent flange reaction force by using flange thickness direction bending moment equilibrium, but these methods are complicated. An action point correction factor of L-type flange is proposed to consider the effect of flange deformation and to expand the applicable range of flange dimension. The results show good agreement with those by the formula of Seidel at the ultimate condition by using load transmitting factor for L-type flange proposed in this paper.

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巻号一覧 風力エネルギー

風力エネルギー Vol. 40(2016) No. 2

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特集１ 新役員、学会発展に向けた抱負を語る

特集２ 風力発電に関連した国内外の風洞設備の紹介

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連載「わがマチわがフルサト」ー地域創生、文化、名所、新エネ・再生エネ、風力発電

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複雑地形における超音波風向風速計を用いた高精度風況解析 （青森県下北地方岩屋ウィンドファームにおける２高度観測)

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巻号一覧
風力エネルギー

特集１　新役員、学会発展に向けた抱負を語る

特集２　風力発電に関連した国内外の風洞設備の紹介

複雑地形における超音波風向風速計を用いた高精度風況解析
（青森県下北地方岩屋ウィンドファームにおける２高度観測)