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直流断路器是直流系统组网的关键设备.该文针对直流断路器工作模式对集成门极换流晶闸管(integrated gate commutated thyristors,IGCT)特性进行研究,首先结合仿真与实验结果,分析了母线电压、关断电流、缓冲阻容及杂散电感等因素对IGCT关断动态特性的影响.然后以两IGCT串联系统为例,研究了缓冲阻容、杂散电感差异和触发时间差异对串联均压特性的影响.结果表明,触发时间差异对均压效果影响最大,串联系统应尽量保证所选器件和阀体杂散参数的一致性,并通过调整触发时间等方法改善均压效果.接着,该文给出一种自然换流型混合断路器方案,与已有串联辅助开关的方案相比,该方案通态损耗几乎为零、不需水冷散热、控制逻辑简单、系统可靠性高.基于IGCT动态特性和均压特性分析,该文选取合适参数,搭建了4个IGCT串联开关支路,并完成母线电压10 kV、关断电流3.5 kA开通关断实验,不均压系数约为5%.结合快速机械开关,设计并实现了10 Kv自然换流型直流混合断路器,完成了关断电流3.6 Ka的整体实验,关断过电压21.4 Kv,验证了该方案的可行性.近期还完成了40 Kv/3.4 Ka的实验,为中高压直流断路器的实际工程应用奠定了坚实基础.“,”DC circuit breaker is one of the key technologies of DC power grid networking. This paper analyzed the influence of voltage, turn-off current, snubber resistor and capacitor, and stray inductance on the dynamic characteristics of IGCT. Then taking two integrated gate commutated thyristors (IGCT) series system as an example, the characteristics of unbalanced voltage-sharing caused by the difference of snubber resistor and capacitor, stray inductance and trigger time were studied. The results showed that the trigger time synchronization had the greatest impact on voltage-sharing. To improve series characteristics, trigger time should be adjusted, and consistency of devices and valve body parameters should be improved, etc.. Then, this paper presented a hybrid breaker topology based on natural current transfer, which had low conduction loss, no water cooling system, simple control logic and high reliability. Based on IGCT characteristics analysis, appropriate parameters was selected, and a four IGCT series system was set up, which successfully turned off 3.5 kA under 10 kV, with nonuniformity coefficientof 5%; combining with fast mechanical switch, the 10 kV DC hybrid circuit breaker was developed and successfully turn off 3.6 kA with overvoltage of 21.4 kV, which verified the feasibility of this topology. Recently, 40 kV/3.4 kA experiment had been completed, which had laid a solid foundation for practical engineering application of the high voltage DC circuit breaker.