基于电容自然充电换相的混合式直流断路器设计与仿真  

Design and Simulation of Hybrid DC Circuit Breaker Based on Capacitor Natural Charging Commutation

作　　者：范兴明[1] 李涛 张鑫[1] Fan Xingming;Li Tao;Zhang Xin(School of Mechanical and Electrical Engineering,Guilin University of Electronic and Technology,Guilin,541004,China)

机构地区：[1]桂林电子科技大学机电工程学院,桂林541004

出　　处：《电工技术学报》2024年第11期3510-3521,共12页Transactions of China Electrotechnical Society

基　　金：国家自然科学基金项目(61741126);广西自然科学基金项目(2022GXNSFAA035533)资助。

摘　　要：以晶闸管作为主断器件是降低混合式直流断路器造价和技术难度的手段之一,电容电压是此类直流断路器能够顺利开断直流故障的关键影响因素。现有结构中电容大多为预充电型,但预充电方式和电容电压的维持较为复杂。因此,该文提出一种基于电容自然充电换相的混合式直流断路器,利用母线电压与预充电电容的电压差值实现电容的预充电和电容电压的自动维持,从而保证断路器的开断能力。此外该断路器还具备二次开断能力,可以满足极短时间内重复开断的需求。针对所提断路器的工作过程和元器件参数进行了详细的理论推导,基于PSCAD/EMTDC建立单端等效和四端柔性直流电网模型验证了所提结构的适用性。最后与其他方案进行比较,结果表明,所提方案在开断速度、电容预充电方式和二次开断方面具备一定优势。Hybrid DC circuit breakers based on IGBT as the main breaking device are expensive,which limits the large-scale application of hybrid DC circuit breakers.Thyristor is one of the means to reduce the cost and technical difficulty of hybrid DC circuit breaker as the main breaking device.This type of hybrid DC circuit breaker generally combines pre-charged capacitor to complete the breaking task,but the pre-charge mode of the existing structure capacitor and the maintenance of the capacitor voltage are more complicated.Therefore,this paper proposes a hybrid DC circuit breaker based on the natural charging commutation of the capacitor.The initial energy storage of the capacitor and the automatic maintenance of the capacitor voltage are realized by using the voltage difference between the DC bus and the capacitor,so as to ensure the breaking ability of the circuit breaker.After the interruption,the capacitor voltage can be recharged again whether the line fault is restored or not,which can meet the demand of secondary interruption in a short time.Firstly,the topology and working process of the proposed topology are introduced and analyzed.According to the function of each branch,the proposed branch is named as the main branch,the transfer branch composed of thyristors,the capacitor natural charging branch,the capacitor commutation branch,the energy absorption branch.There is no charging switch in the capacitor natural charging branch,which is the key to realize the initial energy storage of the capacitor and the automatic maintenance of the capacitor voltage,also determines whether the proposed circuit breaker can successfully break the DC fault.Then the parameters of the main components in the above branches are designed,and the general principles of parameter design and the recommended range of values are given.The following two points determine whether the proposed scheme can successfully and reliably break the DC fault:(1)The peak value of the oscillating current generated by the capacitor commutation branch needs

关 键 词：混合式直流断路器 晶闸管 预充电 二次开断 

分 类 号：TM561[电气工程—电器]