弧后电流是断路器零区物理特性的重要研究内容之一，研究弧后电流特性可完善零区真空电弧模型，丰富直流真空电弧理论，提高直流断路器开断能力，具有重要的科学意义。目前针对零区特性的研究多侧重于鞘层增长过程的仿真及弧后介质强度测量，而对零区弧后电流特性的研究相对较少。本项目侧重于研究不同动态影响因素(如分断速度、电流幅值、换流频率、燃弧时间、恢复电压上升率等)下的弧后电流特性，揭示弧后电流与直流断路器开断能力之间的影响关系，得到开断极限对应的弧后电流临界值，给出新的直流断路器开断极限判据。最后通过合理的控制方法，优化弧后电流特性，提高真空直流断路器的开断能力。研究成果可用于判断直流断路器是否达到开断极限，并提高其开断性能，为未来真空直流强迫分断用灭弧室设计奠定理论和试验基础。

The post-arc current is an important part of circuit breaker’s current-zero characteristics, which influence the breaking capacity of breakers. Studying the post-arc current is useful for improving the arc model of current-zero, enriching the theory of vacuum DC arc. Nowadays, the investigations on the current-zero characteristics mainly focus on the simulation of sheath growth and measurement of dielectric strength. Few works were done on the characteristics of post-arc current. In this project, the investigations focus on the characteristics of post-arc current for different dynamic factors, such as opening speed, commutating frequency, current amplitude and so on. By the study, the relationship between the post-arc current and breaking capacity is revealed and the critical post-arc current is obtained. It provides a flesh evidence to judge the breaking capacity of vacuum DC circuit breakers. In addition, the control method is put forward to optimize the post-arc current characteristics and improve the breaking capacity. The results can be used to judge that whether the breakers have achieved its limitation, improve the breaking capacity and guide the design of vacuum interrupters for vacuum DC interruption in future.