基于串联晶闸管强迫过零关断技术的混合式高压直流断路器  

Hybrid HVDC Circuit Breaker Based on Series-connected Thyristors with Forced Zero Crossing Technique

作　　者：封磊[1,2] 苟锐锋 杨晓平 王江涛 李超 卓放 

机构地区：[1]西安交通大学电气工程学院,西安710049 [2]西安西电电力系统有限公司,西安710065

出　　处：《高电压技术》2018年第2期388-394,共7页High Voltage Engineering

基　　金：国家重点基础研究发展计划(973计划)(2015CB251001;2015CB251004)~~

摘　　要：为了提高混合式直流断路器的开断能力,降低半导体器件的使用成本,提出了一种基于串联晶闸管强迫过零关断技术的具备双向开断能力的混合式直流断路器拓扑方案。在分析关断过程的基础上,推导了串联晶闸管阀与二极管阀组件反向恢复过程中均压回路的参数设计方法,然后以10 k V样机为例,开展了主支路和转移支路器件选型与参数设计,并搭建了10 k V直流断路器原理样机及其实验回路。研究结果表明：正常运行时,主支路由机械开关和少量的全控型半导体器件串联构成,其损耗较小;在开断电流时,故障电流首先转移至晶闸管阀支路,再通过放电回路注入反向电流迫使晶闸管阀过零关断,最后通过耗能支路吸收系统感性能量。原理样机实现了直流电压10 k V下短路电流峰值为8.8 k A的过零快速关断、且开断时间小于3 ms;转移支路可通过调整半导体器件的串联数量和选型大幅提升直流断路器的电压等级和故障电流耐受能力;串联二极管阀能在大电流关断暂态过程中抑制晶闸管器件的反向恢复过电压,降低晶闸管器件的损坏风险;在混合式直流断路器的换流和关断阶段,无需针对串联的晶闸管器件调整触发时间与匹配参数。综上所述,所提出的混合式直流断路器具有快速直流短路故障清除能力,可以作为未来柔性高压直流输电系统组网的工程实施方案之一。To improve the interruption capability and reduce the semiconductor cost of the hybrid DC circuit breaker,we proposed a new hybrid DC circuit breaker topology with bidirectional interruption based on forced zero crossing series-connected thyristors technique. By analyzing the breaking principle, we derived the parameters of voltage balancing circuit for the series-connected thyristors and diodes valves during the reverse recovery stage. Then, taking a 10 k V prototype for example, we carried out the devices selection and parameters design of the main and transfer branch. At last, a 10 k V DC breaker principle prototype and its test circuit were set up. The study results show that, in normal operation, the mechanical switch and small amount of series-connected full-controlled devices in main branch handle the low conduction loss. In case of interruption, the fault current is commutated to thyristors valve, and the current of thyristors valve is forced to zero by injecting current inversely for turning off thyristors. At last the inductive energy is dissipated by the energy absorbing branch. The principal prototype breaks the short current of 8.8 k A peak value under 10 k V voltage where the interruption time is less than 3 ms. The voltage rating and fault current withstanding capability of the breaker can be easily improved by adjusting the series-connected number and type of the semiconductor devices in the transfer branch. The diode valves can suppress the over-voltage of thyristor devices during reverse recovery under the high current interruption transient condition to decrease the risk of damage for thyristors. There is no need to adjust triggering time and match parameters for thyristors in series during the commutation and interruption stage of the hybrid breakers. In conclusion, the proposed hybrid DC breaker has the short-circuit fault fast clearing capability, so it is more suitable for the practical project of the future flexible high-voltage DC grid.

关 键 词：混合式 断路器 串联 晶闸管 高压直流 电压源换流器 

分 类 号：TM561[电气工程—电器]