Vacuum Interrupter Steam Shield, And The Degree Of Vacuum Monitoring Applications

This paper designs a device of testing the arc shield voltage in thevacuum interrupter, and makes a study of the arcing and after-arcingrecovery characteristics of the arc shield by measuring the arc current, thearc voltage, the recovery voltage and the arc shield voltage. Not only doesit study the plasma characteristics of the arcing and after-arcing betweencontacts, but also its diffusion to outside of the contacts and its effect on thearc shield. For the first time, it proves the non-stability of the plasmadiffusion of after-arcing by experiments.The paper establishes a mathematic model that describes therelationship between the arc voltage, the recovery voltage and the arc shieldvoltage. lt makes a detailed theoretic analysis of the plasma changing lawsbetween contacts and the arc shield gap arc in the arcing process andafter-arcing recovery process. The model has achieved the same results asthe experiment results.By testing the arc shield voltage in different vacuum degree, it provesthat the arc shield voltage method will be an effective online testing methodwhen the vacuum degree is or lower than lPa,but the method will be no usewhen the vacuum degree is higher than 10-2Pa.