絶縁系における部分放電特性
 [研究内容] 現在，高温超電導ケーブル(High temperature superconducting cable: HTS cable)の技術開発が世界各国で行われており，日本においても実系統への導入試験といった実用化に向けての開発が進められている．高温超電導ケーブルの利点としては，現用のケーブルに比べて非常に軽量・コンパクトな上に大容量化を実現できる点などが挙げられる．しかしながら，高温超電導ケーブルの絶縁構成である液体窒素／積層テープ複合絶縁系における部分放電(PD)特性・メカニズムについては十分に把握されておらず，絶縁設計手法は確立していないのが現状である． そこで，実用的かつ合理的な絶縁設計の確立を目的とし，液体窒素／積層テープ複合絶縁系におけるPD特性・メカニズムについて検討を行っている．実験はステンレス製のクライオスタットを用いており，液体窒素浸漬状態で交流印加電圧に対し最大150kVまでコロナフリーであるブッシングが挿入されている． 本実験系においては，最大で1pC程度の微小なPDを検出することが可能である．具体的な検討項目は ・PD挙動の電界依存性および時間推移特性 ・加圧過冷却液体窒素環境下におけるPD特性 ・V-t特性，体積効果 等である． [学術論文] (9) H.Okubo, H.Kojima, F.Endo, K.Sahara, R.Yamaguchi and N.Hayakawa "Partial Discharge Activity in Electrical Insulation for High Temperature Superconducting (HTS) Cables" IEEE Trans. on Dielectrics and Electrical Insulation, Vol.15, No.3, pp.647-654, 2008 (8) H.Okubo, H.Kojima, F.Endo, K.Sahara and N.Hayakawa "Impulse and ac Partial Discharge Inception and Breakdown Characteristics of LN2 / Polypropylene Laminated Paper Composite Insulation System" IEEE Trans. on Dielectrics and Electrical Insulation, Vol.13, No.3, pp.664-669, 2006 (7) N.Hayakawa, M.Nagino, H.Kojima, M.Goto, T.Takahashi, K.Yasuda and H.Okubo "Dielectric Characteristics of HTS Cables Based on Partial Discharge Measurement" IEEE Trans. on Aplied Superconductivity, Vol.15, No.2, pp.1802-1805, 2005 (6) N.Hayakawa, T.Kobayashi, M.Hazeyama, T.Takahashi, K.Yasuda and H.Okubo "Partial discharge inception characteristics of LN2/PP laminated paper composite insulation system for high temperature superconducting cable" IEEE Trans. on Dielectrics and Electrical Insulation, Vol.12, No.1, pp.166-174, 2005 (5) H.Okubo, M.Hazeyama, N.Hayakawa, S.Honjo, T.Masuda "V-t characteristics of Partial Discharge Inception in Liquid Nitrogen/PPLP Composite Insulation System for HTS Superconducting Cable" IEEE Transaction on Dielectric and Electrical Insulation, Vol.9, No.6, pp.945-951 (2002) (4) M.Hazeyama, T.Kobayashi, N.Hayakawa, S.Honjo, T.Masuda, H.Okubo "Partial Discharge Inception Characteristics under Butt Gap Condition in Liquid Nitrogen/PPLP Composite Insulation System for High Temperature Superconducting Cable" IEEE Transaction on Dielectric and Electrical Insulation, Vol.9, No.6, pp.939-944 (2002) (3) M.Hazeyama, T.Kobayashi, N.Hayakawa, S.Honjo, T.Masuda, H.Okubo "V-t characteristics for Partial Discharge Inception of High Temperature Superconducting Power Transmission Cables" Physica C, Vol.372-376, No.3, pp.1551-1554 (2002) (2) 枦山盛幸，早川直樹，松尾公義，高橋芳久，増田孝人，廣瀬正幸，大久保仁 "液体窒素／積層テープ複合絶縁系の部分放電開始特性に及ぼすバットギャップの影響" 電気学会論文誌B, Vol.121, No.10, pp.1325-1330 (2001) (1) 枦山盛幸，早川直樹，大久保仁 "液体窒素／固体複合絶縁系の気泡存在時における部分放電開始のV-t特性" 電気学会論文誌A, Vol.121, No.4, pp.345-350 (2001) [発表実績] (13) N.Hayakawa, R.Yamaguchi, Y.Ukai, H.Kojima, F.Endo and H.Okubo “Partial Discharge Activities under AC/Impulse Superimposed Voltage in LN2/Polypropylene Laminated Paper Insulation System for HTS Cables” 9th European Conference of Applied Superconductivity, HSZ 04 (2009) (12) N.Hayakawa, R.Yamaguchi, H.Kojima, F.Endo and H.Okubo "Partial Discharge Inception Strength in a Full-scale HTS Cable Based on LN2/Polypropylene Laminated Paper Insulation" 16th International Conference on Dielectric Liquids (2008) (11) N.Hayakawa, K.Sahara, R.Yamaguchi, H.Kojima, F.Endo and H.Okubo "Partial Discharge Activity for Insulation System of High Temperature Superconducting Cables" International Symposium on High Voltage Engineering (2007) (10) N.Hayakawa, S.Ueyama, H.Kojima, F.Endo, T.Masuda, M.Hirose: “Electrical Insulation Characteristics of HTS Cables under Quench-induced Thermal Stress Condition” Applied Superconductivity Conference, 1LB06, 2006 (9) N.Hayakawa, S.Ueyama, H.Kojima, F.Endo, T.Masuda, M.Hirose "Electrical Insulation Characteristics of HTS Cables under Quench-induced Thermal Stress Condition" Applied Superconductivity Conference, 1LB06 (2006) (8) N.Hayakawa, K.Sahara, H.Kojima, F.Endo and H.Okubo "Partial Discharge Inception and Breakdown Characteristics of LN2 / Polypropylene Laminated Paper Composite Insulation System for HTS Cables" IEEE Conference on Electrical Insulation and Dielectric Phenomina. (2005) (7) H.Okubo, M.Nagino, H.Kojima, N.Hayakawa, T.Takahashi and K.Yasuda "Impulse and ac PD Inception Characteristics of LN2/Polypropylene Laminated Paper Composite Insulation System" 15th International Conference on Dielectric Liquids (2005) (6) N.Hayakawa, T.Kobayashi, M.Hazeyama, T.Takahashi, K.Yasuda, H.Okubo "Volume Effect of Partial Discharge Inception Characteristics in High Temperature Superconducting Cable" 6th International Conference on Insulated Power Cables, A-3-5 (2003) (5) N.Hayakawa, M.Hazeyama, T.Kobayashi, T.Takahashi, K.Yasuda, H.Okubo "V-t characteristics at PD inception for LN2 Impregnated HTS Cable Insulation System" 6th International Conference on Insulated Power Cables, A-3-6 (2003) (4) H.Okubo, M.Hazeyama, T.Kobayashi, N.Hayakawa, T.Takahashi, K.Yasuda "PD Inception Characteristics in LN2/PP Laminated Paper Composite Insulation System for HTS Cable" 7th International Conference on Properties and Applications of Dielectric Materials, R-353 (2003) (3) M.Hazeyama, N.Hayakawa, S.Honjo, T.Masuda, H.Okubo "Partial Discharge Inception V-T Characteristics for Liquid Nitrogen/PPLP Composite Insulation System" 14th International Conference on Dielectric Liquids, pp.123-126 (2002) (2) M.Hazeyama, N.Hayakawa, K.Matsuo, T.Masuda, H.Okubo "V-t characteristics for Partial Discharge Inception of High Temperature Superconducting Power Transmission Cables" 5th European Conference of Applied Superconductivity, E4.1-02 (2001) (1) N.Hayakawa, M.Hazeyama, H.Okubo "Breakdown and Partial Discharge Inception Characteristics of Liquid Nitrogen" International High Voltage Workshop 2000 Newport Beach, USA |