Reliability and Performance of Composite Electrical Insulation at Cryogenic Temperature for Superconducting Power Apparatus

超导电力设备低温复合电绝缘的可靠性和性能

• 批准号: 15560240
• 负责人: NAGAO Masayuki
• 金额: $ 2.3万
• 依托单位: Toyohashi University of Technology
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 2003
• 资助国家: 日本
• 起止时间: 2003 至 2004
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-15560240/
• 关键词: Cryogenic Temperature; Spacer; Foreign Particles; Creeping Discharge; Electric Breakdown; Small Gap; 極低温絶縁; 微小ギャップ; 帯電; 紙-氷複合絶縁; 導電性異物; 微小傷; 氷・絶縁紙複合絶縁系; 氷結時圧力

The world's largest class superconducting coil is used for the "Large-scale Helical Device". Its electrical insulation system might be exposed to considerably severe multiple stresses including cryogenic temperature, large mechanical stresses and strong magnetic fields. It is therefore very important to study its electrical insulation performance in order to establish the reliability of the coil. If a superconductor quenches from superconducting state to normal state, the liquid coolant vaporizes very easily and turns into high-density gas at cryogenic temperature, which may reduce its withstanding voltage. Furthermore, it is very difficult to completely remove foreign particles from the insulated space. So it is required to clarify the influence of foreign particles and electrification on the insulation performances.This research was conducted using electrode system that simulated the insulation system to investigate the behavior of small gaps and foreign particles with the breakdown characteristics of insulation. The breakdown voltage of insulation system that has a small gap in liquid helium is shown in Fig.1. The breakdown voltage increased with decrease of voltage rising rate when the polarity of voltage was positive, but the breakdown voltage was almost constant with decrease of voltage rising rate when the polarity of voltage was negative. Assuming that positive charge can move along the spacer surface that is in contact which the metallic electrode, lower rising rate of applied voltage would bring more significant charge accumulation on the spacer, leading to the field enhancement which reduces the breakdown voltage. It became also clear that conductive foreign particles affect the breakdown voltage while dielectric foreign particles do not.

“大型螺旋装置”采用了世界最大级别的超导线圈。其电气绝缘系统可能会承受相当严重的多重应力，包括低温、大机械应力和强磁场。因此，研究其电绝缘性能对于确定线圈的可靠性非常重要。如果超导体从超导状态淬灭到正常状态，液体冷却剂很容易汽化并在低温下变成高密度气体，这可能会降低其耐压。此外，从隔热空间中完全去除异物是非常困难的。因此需要明确异物和带电对绝缘性能的影响。本研究采用模拟绝缘系统的电极系统来研究小间隙和异物对绝缘击穿特性的影响。具有小间隙的绝缘系统在液氦中的击穿电压如图1所示。当电压极性为正时，击穿电压随着电压上升速率的减小而增大，而当电压极性为负时，击穿电压随着电压上升速率的减小而几乎恒定。假设正电荷可以沿着与金属电极接触的间隔物表面移动，施加电压的较低上升速率将在间隔物上带来更显着的电荷积累，导致场增强，从而降低击穿电压。还清楚的是，导电异物会影响击穿电压，而介电异物则不会。

项目成果

液体窒素中における多層絶縁紙-氷複合絶縁系の導電性異物による絶縁破壊特性と部分放電に及ぼす影響

液氮中导电异物对多层绝缘纸-冰复合绝缘系统击穿特性和局部放电的影响

• 发表时间: 2005
• 期刊: 平成17年電気学会全国大会 講演論文集[2] No.2-074
• 作者: 花村大樹;長尾雅行;穂積直裕;村本裕二;小崎正光
• 通讯作者: 小崎正光

Influence of Microbubble on Breakdown Voltage of Elctrode System Imitated Gap in LN_2

LN_2中微泡对仿间隙电极系统击穿电压的影响

• 发表时间: 2005
• 期刊: 2005ANNUAL MEETING RECORD I.E.E JAPAN No.2-71
• 作者: M.Shimomura;Y.Murakami;N.Hozumi;M.Nagao;Y.Muramotoi;A.Minoda;M.Kosaki;S.Yamada
• 通讯作者: S.Yamada

石塚 岳弘: "液体ヘリウム中におけるスペーサの帯電が微小ギャップの放電に及ぼす影響"平成16年電気学会全国大会 講演論文集[1]. 13 (2004)

Takehiro Ishizuka：“液氦中隔离物充电对微间隙放电的影响”日本电气工程师学会 2004 年全国会议论文集 [1]（2004 年）。

Influence of Electrode Arrangement and Micro Bubbles on Breakdown Voltage along Spacer in LN_2

LN_2中电极排列和微气泡对沿隔离物击穿电压的影响

• 发表时间: 2004
• 期刊: RECORD OF 2004 TOKAI-SECTION JOINT CONFERENCE OF THE EIGHT INSTITUTES OF ELECTRICAL AND RELATED ENGINEERS No.O-66(CD-ROM)
• 作者: M.Shimomura;Y.Muramoto;N.Hozumi;Y.Murakami;M.Nagao;A.Minoda;M.Kosaki;S.Yamada
• 通讯作者: S.Yamada

液体窒素中における多層紙-氷複合絶縁系の導電性異物による絶縁破壊特性と部分放電に及ぼす影響

液氮中导电异物对多层纸冰复合绝缘系统击穿特性和局部放电的影响

• 发表时间: 2005
• 期刊: 平成17年電気学会全国大会 講演論文集[2] No.2-074
• 作者: 花村大樹;長尾雅行;穂積直裕;村本裕二;小崎正光
• 通讯作者: 小崎正光