Multiple re-ignition overvoltage is determined by dielectric recovery strength after interruption of small inductive currents in vacuum. We established a micro-physical model for small inductive current interruption in vacuum

with which the influence of load parameters on the re-ignitions can be determined

so as to reveal the sheath development process after interruption of small inductive current in vacuum. The following micro-parameters were determined

including the ion density

ion speed

development of electric field

and potential distribution under various TRVs. A critical electric field strength at the cathode was chosen as a criterion for the re-ignition. The simulation results show the following influence of load parameters on the re-ignitions of small current inductive current interruption in vacuum. A higher load capacitance or a higher load inductance will decrease the sheath development speed and the maximum field strength

which decreases the overvoltage and the risk of re-ignition. The sheath speed and the maximum field strength does not change with the increase of the equivalent resistance

but the load current decreases with the increase of the equivalent resistance. A lower load current reduces sheath velocity

which results in a lower maximum electric field strength. Therefore

it decreases the risk of re-ignition.