With the well flexibility to expand for medium & high voltage large power application

the DC vacuum circuit breaker（VCB） based on active forced current commutation is becoming a very important development direction for DC interruption technology. For a 10 kV DC VCB

lots of experimental studies for the high current commutation interruption（CCI） process were conducted after a further analysis of the CCI characteristics in this paper. The experimental results indicated that the VCB could not interrupt reliably at the current zeros for the peak arc current about 23 kA and the fall rate about 300 A/μs. In addition

some dispersion and randomness took place in the vacuum gap（VG） post-arc dielectric recovery（PADR） process. In order to improve the high current PADR characteristics

a DC VCB CCI scheme was proposed with a diode connected in series

which could provide a current zero interval for the high current vacuum arc through the diode reverse blocking. According to the comparative interruption test results under the same parameters

although the process of dielectric recovery

dielectric breakdown

dielectric recovery’ might be repeated continuously during the diode reverse blocking

the arc reigniting would not happen in the VG. Finally

the VG was able to built enough dielectric strength before the commutation capacitor voltage polarity becoming positive

so that reliable interruption of the high DC current could be realized. Meanwhile

under the test conditions

it would take at least 85 μs to completely recover the dielectric strength in the post-arc stage.