Abstract: During the operation of the subbstation equipment,the”SF6 gas pressure low locking on/off sound”emitted by the circuit breaker is an abnormality that mayoccur in the operation of the substation.The treatrment of this abnormality involves awide range.When a fault occurs,the circuit breaker will refuse to operate,skip the level,and trip,endangering thesafe and stable operation of the power grid.in this paper,taking Siemens 220k3ap 1dt as an example Thecauses of the secondary circuit are analyzed in depth and the treatment methods and measures after the abnormal signal is sent out