Toshiba’s 300 kV gas circuit breaker (GCB) and three-phase gas-insulated bus (GIB) — both using only naturally derived gas — have been selected for adoption by TEPCO Power Grid. This is the world’s first adoption of these two products. A formal order contract is to be signed going forward, with delivery scheduled for FY2029 for the GCB and FY2030 for the GIB. Toshiba regards this as “a significant milestone toward the practical application of naturally derived gases in high-voltage equipment.”
In power transmission and substation equipment such as GCBs and GIBs, sulfur hexafluoride (SF₆) gas — with its superior dielectric performance — has long been used to provide electrical insulation between the current-carrying conductor and the surrounding metal tank. However, since SF₆ has a global warming potential (GWP) approximately 25,000 times that of carbon dioxide (CO₂), leakage of the gas poses a significant environmental impact, making its reduced use a key challenge.
From the perspectives of human and environmental safety, ease of handling, and reliability, Toshiba has positioned naturally derived gas as the solution for eliminating SF₆, and has continued its development accordingly. Under the brand name “AEROXIA,” Toshiba has already commercialized gas-insulated switchgear (GIS) using this technology.