In this paper

the problems of the existing SF

6

gas density monitor that they are prone to vibration and oil leakage are analyzed. In order to solve these problems

oil free vibration resistance type SF

6

gas density monitor is proposed and developed. Vibration resistance is not achieved by silicon oil filling in this density monitor

but the design of the tripping preventing system. The shock and vibration are generated when the switchgear opens and recloses

the micro switches（contacts）are physically brought away from where they can possibly trip so as to avoid undesired operation. In this way

the density monitor escapes from the impact of shock and vibration and avoids giving a signal（micro switch）when

gas density is normal

and the safe operation of the power network is maintained. After more than 2 years of field application

it has proved that the performance is reliable and meets the requirements of the oil free and the reclosing of circuit breaker.