Summary
Gas-insulated switchgear (GIS) employing sulfur hexafluoride (SF₆) gas has contributed significantly to the design of compact substations and high operational reliability in Japan, owing to its excellent dielectric and current interruption characteristics. However, because SF₆ gas has an extremely high global warming potential (GWP), emission regulations have been progressively tightened, particularly in Europe and the United States. As a result, the transition to SF₆-free technologies is accelerating in Japan as well, supported by the roadmap issued by the Japan Electrical Manufacturers' Association (JEMA) and collaborative activities involving electric utilities and manufacturers. Discussions regarding the early deployment of SF₆alternative technologies are also intensifying in international forums such as CIGRE. Among various candidate gases, synthetic air composed primarily of nitrogen and oxygen and derived from natural sources has been attracting growing attention due to its favorable environmental profile, safety, and stable supply chain.
Read more Read lessResearch and development toward the practical implementation of synthetic-air-insulated switching technology is progressing, mainly driven by international regulatory trends. However, compared with SF₆ gas, technical issues remain regarding dielectric recovery performance and current switching capability. Switching duties required in actual operation, such as bus-transfer current interruption by disconnectors (DS) and electromagnetically induced current interruption by earthing switches (ES), must be addressed with suitable arc-quenching principles and design considerations. In this paper, an investigation focusing on the switching performance of simplified DS and ES insulated with synthetic air is presented. The performance limitations are evaluated, and key technical issues for future SF₆-free GIS development are identified.
Additional informations
| Publication type | Session Materials |
|---|---|
| Reference | A3_10767_2026 |
| Publication year | |
| Publisher | CIGRE |
| Country | Japan |
| Study committees | |
| File size | 1 MB |
| Price for non member | 30 € |
| Price for member | 30 € |
Authors
ONISHI Tomoya - Toshiba Energy systems & Solutions Corporation Japan; IWANADE Naokazu - Toshiba Energy systems & Solutions Corporation Japan; KOIKE Toru - Toshiba Energy systems & Solutions Corporation Japan; MUKAIDA Akihisa - Toshiba Energy systems & Solutions Corporation Japan; OZEKI Taiki - Chubu Electric Power Grid Co., Inc. Japan; IWAHARA Kentaro - Chubu Electric Power Grid Co., Inc. Japan
Keywords
Synthetic Air, Bus Transfer Current, Electromagnetically Induced Current, Switching
