The structure of compact air insulated switchgear is all-metal fully insulated enclosed. The primary live part is arranged in the enclosed box. The insulating medium between the charged conductors and the relative ground is air. The air pressure in the sealed box is always the same as that in the environment. The internal and external gas pressure is balanced by the device with air filtering function. The mode of arc extinguishing is vacuum arc extinguishing. It should meet the requirement of GB 3906, adopt the maintenance-free structure of fixed assembly, and configure the isolation/grounding switch (closing, isolation and grounding) with three-position isolation structure. The structure design should enable it to operate, inspect, maintain and operate safely, as well as to check the nuclear phase, grounding of connecting cables, locating of cable faults, connecting cables or the like. Voltage test of the device.