2000 Fiscal Year Final Research Report Summary
Development of Design Method of Electrical Insulation and Improvement Method of withstand Strength in HTC Superconducting Power Apparatus
| Project/Area Number |
10305021
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| Research Category |
Grant-in-Aid for Scientific Research (A).
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
電力工学・電気機器工学
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| Research Institution | KYUSHU UNIVERSITY |
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Principal Investigator |
HARA Msanori KYUSHU UNIVERSITY Graduate School of Information Science and Electrical Engineering Professor, 大学院・システム情報科学研究院, 教授 (30039127)
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| Co-Investigator(Kenkyū-buntansha) |
IMASAKA Kiminobu KYUSHU UNIVERSITY Graduate School of Information Science and Electrical Engineering Assistant, 大学院・システム情報科学研究院, 助手 (40264072)
SUEHIRO Junya KYUSHU UNIVERSITY Graduate School of Information Science and Electrical Engineering Assistant professor, 大学院・システム情報科学研究院, 助教授 (70206382)
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| Project Period (FY) |
1998 – 2000
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| Keywords | High Tc Superconducting / Electrical insulatio / Modeled bare coil electrodes / Quenching phenomena / Bubble formation / Vapor locking / Partial discharge / Void |
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| Research Abstract |
Recent advancements in High Tc Superconducting (HTS) wire technology have stimulated increasing interest in the past few years in the development of high Tc superconducting power apparatus. To ensure the feasibility of the introduction of HTS power apparatus into present electric power systems, the reliability of the electrical insulation must be incorporated in the design from the early beginning of the development of the apparatus. The aim of the present study is essentially to establish the electrical insulation policy of HTS power apparatus taking into account of the quenching phenomena which will not only cause bubble formation in insulation medium but also create a high voltage drop across the coil layer. For this purposes, this research project was divided into three parts : (1) Studies on electrical breakdown mechansm and characteristics with modeled bare coil electrodes, (2) Studies on bubble behavior under quenching condition with a modeled HTS coil and (3) Void discharge studies.
The results suggests the following about the electrical insulation policy. Since the vapor locking can appear in the cooling channel of HTS superconducting coil at quenching state, the required insulation space should be determined as the insulation medium being nitrogen gas at temperature of quenched conductor if the quenching is unavoidable and high reliable electrical insulation is required. Instulation material under cryogenic conditions has better long time V-t characteristics than under operating temperatures of conventional electric power apparatus. However, partial discharge in voids included in solid insulator under voltage stresses with harmonics, should be considered to be one of the important degradation factors of insulation material. Moreover, the temperature change at any portion in solid insulator should be suppressed lower than 5K/min. to avoid the formation of crazy crack by the heat stress.
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