一种基于两阶段电流转移的新型直流断路器  

Novel DC Circuit Breaker Based on Current Commutation Principle

作　　者：林友福 陈敏 王万亭 

机构地区：[1]杭州恒信电气有限公司,浙江临安311300

出　　处：《高压电器》2015年第4期139-144,共6页High Voltage Apparatus

摘　　要：基于高速开关(fast-opening switch,FS)和并联电容电流强制转移原理的混合型直流断路器在直流系统短路电流分断中具有广泛的应用。但是,通过单阶段转移将故障电流从FS转移至并联电容器时,由于转移过程持续时间短,电容器需要在很短的时间内吸收系统电感中存储的能量,因此高速开关触头间过电压上升速率非常高,容易引起FS发生击穿而导致开断失败。针对上述问题,文中提出了一种基于两阶段电流转移的新型直流断路器,通过转移电路的晶闸管控制故障电流分两阶段给电容器充电,不仅可以实现FS无弧打开,而且可以显著降低开断过程中FS两端的过电压上升速率。此外,分断完成后电容器上的电压极性与初始状态一致,不需要重复充电。文中基于MATAB Simulink对该断路器在中压直流系统中不同短路电流上升率情况下的分断过程进行了仿真,并且与传统的单阶段转移过程进行了比较。最后,利用合成回路模拟直流短路故障,完成了故障电流开断实验研究,验证了仿真模型的可行性。The DC hybrid circuit breaker based on fast-opening switch（FS）and parallel connected capacitor has been widely applied in the fault current breaking of DC grid. However, when the fault current is commutated from FS to the parallel connected capacitor with single-stage current commutation, the capacitor has to absorb large energy stored in the system inductance within a short time, so a high over-voltage rate of rise occurs between contacts, which will lead to a failed breaking. In view of this, a novel DC circuit breaker based on current commutation has been proposed in this paper. By controlling the thyristor in the commutation branches, the fault current is commutated in two stages, which can not only realize the arc-less open of FS, but also decrease the over-voltage rate of rise obviously. Besides, the voltage polarity of capacitor after breaking is same as the initial state, which can avoid recharging. The simulation model of the fault current breaking is constructed on MATLAB Simulink platform under different conditions in medium voltage DC（MVDC） system, and the overvoltage of the single-stage commutation and the two-stage commutation during the fault current breaking are compared. Finally, the fault current breaking test based on synthesis loop is investigated experimentally, which proved that the simulation model is well feasible.

关 键 词：高速开关 直流断路器 两阶段电流转移 故障电流开断 

分 类 号：TM561[电气工程—电器]