Method and device for quickly replacing sulfur hexafluoride/nitrogen mixed insulating gas on site

The invention provides a method and a device for quickly replacing sulfur hexafluoride/nitrogen mixed insulating gas on site. The device comprises a sulfur hexafluoride gas recovery device, a sulfur hexafluoride/nitrogen mixed gas charging and supplementing device and a high-precision pressure gauge, the sulfur hexafluoride gas recovery device and the sulfur hexafluoride/nitrogen mixed gas filling and supplementing device are respectively connected with a gas taking port of the GIS gas chamber through pipelines, and high-precision pressure gauges are arranged on the connecting pipelines; an electromagnetic valve V1 is arranged on a connecting pipeline of the sulfur hexafluoride/nitrogen mixed gas filling and supplementing device and the gas taking port of the GIS gas chamber, and the gas flowing state is controlled by the electromagnetic valve V1; a pipeline for connecting the sulfur hexafluoride gas recovery device and the gas taking port of the GIS gas chamber is provided with an electromagnetic valve V2, a