In primary-secondary integrated distribution circuit breakers

the transient radiation caused by switching operations may affect the inner secondary devices. However

the existing researches on EMC problems of distribution switching equipment are mostly focused one xperimental tests

which are lack of simulation parts. The objective of this paper is to establish one simulation method which is suitable for researching electromagnetic radiation problems of distributioncircuit breakers

and to verify the method by experiments. By analyzing features of near-field radiation of distribution circuit breakers

finite integration time domain（FITD） is considered as a suitable calculating methodology for this electromagnetism model.Next

one simulation model of a 10 kV vacuum circuit breaker is established by the simulation software CST microwave studio

and then an electromagnetic radiation field caused by the inrush current is calculated with FITD. The experimentalm easurement in the same condition is also carried out. The comparison between the simulation and experiment results shows that waveforms of them are similar in tendency and the error range is within 15%

which proves the availability of this simulation method in electromagnetic radiation calculation of distribution circuit breakers.