In order to improve the short-circuit current interruption capability of DC circuit breakers

a parallel interruption scheme of injection enhanced gate transistor（IEGT） based on coupled negative voltage hybrid DC circuit breakers is presented in this paper. Firstly

the topological structure and working principle of power electronic switch are given. Secondly

the influence of stray inductance on the parallel breaking ability of power electronic switch is analyzed

and a cascade bus arrangement scheme is proposed to optimize the stray inductance. Furthermore

the influence of IEGT driving on the parallel breaking ability of power electronic switch is analyzed. The asymmetric structure will lead to inconsistent switching-off of devices

and non-synchronous characteristics of the two devices can be minimized by adjusting the parameters of driving capacitance and resistance. Finally

a 25 kA high current parallel interruption test is carried out for the power electronic switch used in Zhangbei Flexible DC Transmission Project

which can turn off 25 kA current within 3 ms. The research in this paper can guide the structure and parameter design of DC circuit breaker

and provide references for the subsequent development of DC circuit breakers.