News from Japan

In an attempt to reduce global warming, much research and development work has been done on electric power equipment in which SF6 gas insulation is not used. Mitsubishi Electric Corporation, Tokyo, which released 24-kV-rated dry air insulated switchgear in 2000, has completed more than 1,000 switchgear installations in the 12-, 24-, and 36-kV classes. Recently, the company developed 72-kV-rated switchgear which features low-pressurized dry air (gauge pressure < 0.2 MPa-g) insulation, improved electromagnetic actuators and condition-based maintenance (CBM) functions.