2022 Fiscal Year Final Research Report

Numerical Analysis of Local and Global Dielectric Property of Snow for Preventing Large Blackout

Research Project

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Project/Area Number	20K14727
Research Category	Grant-in-Aid for Early-Career Scientists
Allocation Type	Multi-year Fund
Review Section	Basic Section 21010:Power engineering-related
Research Institution	Kagoshima National College of Technology
Principal Investigator	Yaji Kohei 鹿児島工業高等専門学校, 電気電子工学科, 准教授 (80516667)
Project Period (FY)	2020-04-01 – 2023-03-31
Keywords	雪害 / 人工雪 / 誘電率 / 数値電界計算 / 誤差評価 / がいし / フラッシオーバ
Outline of Final Research Achievements	The maximum electric field and effective dielectric constant in the presence of conductive particles floating in an insulating material were studied by numerical calculation. Simulating snow, the shape, arrangement, and filling rate of particles were varied. The spheroidal particles tend to have higher maximum electric fields than spherical particles. Depending on the arrangement of the particles, spheroidal particles may have a higher apparent dielectric constant than spherical particles. The behavior of the error in the Charge Simulation Method were studied using a verified numerical computation. The inverse matrix method and the LU decomposition method when the condition number of the potential coefficient matrix is small were compared. In the case that the condition number is on the order of 10 squared, the relative error of the potentials is found to be about 10 to the -12 power.
Free Research Field	電気絶縁材料、数値電界計算、高電圧工学
Academic Significance and Societal Importance of the Research Achievements	縁体中に導電性粒子が浮遊する場合の最大電界は、粒子の形状、配置、充填率によって影響を受けると考えられており、それらを変化させたときの計算結果は、絶縁数値計算等何らかの手法で確認する必要があった。本研究では、人工雪を模擬して、見かけの誘電率を数値計算により求め、粒子の形状、配置、充填率と電界分布の定性的な関係を明らかにした。数値電界計算の誤差評価は、この方法の精度向上における課題のひとつである。本研究では、電荷重畳法による簡単な電極配置について、電位の相対誤差は10の－12乗程度であることが分かった。この場合、計算結果への影響は小さいが、条件数が大きくなると、計算結果に影響を及ぼす可能性がある。