報告書番号

N12024

タイトル（和文）

ワイヤ支持式着雪サンプラの屋外着雪観測への適用性実証試験

タイトル（英文）

Demonstration tests of applicability of a simple device using a short dummy conductor supported by wire ropes to field observation of snow accretion

概要 （図表や脚注は「報告書全文」に掲載しております）

当所が電線着雪観測のために新規開発したワイヤ支持式着雪サンプラを，日本の降雪地域3ヶ所で着雪観測への適用性に関する屋外実証試験を実施した．自然降雪環境下での上記実証試験により，本装置の模擬電線上で滑らかな電線捻回を伴う筒雪が形成されうること，厳しい風雪環境下でも一冬季にわたり，メンテナンスフリーで観測に使用できることが実証された．強風湿型着雪事例では，着雪サンプラ上での着雪量時系列や着雪に伴う電線ねじれ角が，並行する実線路の観測値と定量的に整合することが明らかになった．一方，弱風下の乾型着雪事例では，地上高数十mにある実線路と比較して，過大な着雪が地上高数mに設置された着雪サンプラ上で頻発した．この違いは，サンプラ位置と上空の実線路における風条件の違いに起因するものと考えられる．さらに，これらの観測データを用いて，実規模線路では取得が困難な着雪体の密度の風速・気温依存性や，着雪量増加率の電線と風向との交差角に対する依存性に関する考察を行った．これらは，着雪量予測精度向上に大きく貢献するものである．

概要 （英文）

Demonstration tests of a simple device using a short dummy conductor supported by wire ropes, which had been newly developed in CRIEPI for field observation of snow accretion, were conducted at three sites in the snow-fall area in Japan. The following results were obtained.
The tests under natural snow fall condition demonstrated that snow sleeves can form around the dummy conductor in the device accompanied with smooth rotation of the conductor, and that the device can be used under severe wind and snow condition with no maintenance at least for one winter season. For wet snow accretion at high wind speeds, the snow mass per unit length accreted on the dummy conductor as well as the rotation angle of the dummy conductor during snow accretion agrees well with that in actual overhead transmission line. For dry snow accretion at low wind speeds, however, markedly larger amounts of snow accretion were often observed on the device installed at several meter height above the ground than those in actual overhead transmission line at several tens meter height above the ground, which was probably due to the difference between the wind conditions at the device and at the actual overhead wires.
Furthermore, the density of the accreted snow and the dependency of the amount of snow accretion on the crossing angle of the wind to conductor were discussed using the obtained observation data. These data can contribute to improvement of prediction methods of snow accretion.

報告者

キーワード