In order to ascertain the vacuum arc current commutation characteristics between the vacuum arc and the parallel-connected shunt resistor

we experimentally investigated the current commutation characteristics of the post arc current measure equipment（PACME）. The test platform of the vacuum arc commutating characteristic between the vacuum circuit breaker and the parallel-connected shunt resistor was established. The influences of the current magnitude

resistance of the shunt resistor

and the arcing time on the current commutation characteristics such as the commutation time and current were researched. According to the data process and simplified analysis of the experimental results

the mathematic description of vacuum arc commutation characteristic was obtained. At last

the PACME based on the vacuum arc current commutation characteristic was tested in the synthetic test circuit. The post arc current of the vacuum circuit breakers was measured

and the influences of the superimposed current of the high voltage circuit and the magnetic arc blow on the test results were analyzed. The test results indicate that the vacuum arc current commutation can be finished20 μs before the current zero

which verifies the validity of the results. In conclusion

the vacuum arc commutation characteristic is gained which is useful for the optimal design of the PACME.