中文摘要：

搭建多端直流输电用直流真空断路器模块,基于连续过渡模型,结合重击穿判据,利用变步长四阶龙格库塔法,对直流真空断路器弧后介质恢复进行仿真分析。仿真结果表明：弧后电流初始变化率高,而后缓慢变化,直至趋近于零;在鞘层发展阶段中,鞘层厚度呈指数趋势变化。采用对照分析方法,研究燃弧能量、触头电侵蚀率及触头间纵向磁场强度对直流真空断路器弧后介质恢复的影响。结果表明：燃弧能量大,触头电侵蚀率高使得弧后初始离子密度大,离子衰减时间长,鞘层发展缓慢;弧前触头间纵向磁场强度大,弧后初始离子密度小,有利于鞘层发展;剩余纵向磁场强度大,离子衰减时间长,抑制鞘层发展。

英文摘要：

The post-arc dielectric recovery （PDR） characteristics of DC vacuum circuit breaker（DCVCB）, installed in multi-terminal high voltage DC grid, was modeled, on the basis of continuous transition scheme and re-breakdown crite- rion,and simulated in variable-step 4th-order Runge-Kutta method. The simulated results show that the post arc current changes in a sharp decrease-increase mode until it slowly approaches to zero. The sheath thickness grows exponentially. The influence of the major variables, including arc energy, contact erosion rate, and longitudinal magnetic field between the contact, on post-arc dielectric recovery was also evaluated. We found that higher arc energy and contact erosion rate result in larger initial ion density,longer ion decay time,and slower sheath development,so the gap may fail to sustain a high post-arc voltage. A stronger fore-arc longitudinal magnetic field reduces the initial ion density and promotes sheath growth;however, large residue longitudinal magnetic field negatively affects DC switching characteristics because it in- creases ion decay time and holds up sheath development.