基于电压源换流器的直流配电限流方案研究

摘要

In order to limit the DC side fault current due to poles short-circuit of the Voltage Source Converters (VSC) DC side in DC distribution network, this paper studies the transient process of different stages during the DC side short circuit faults, and analyzes the protection scheme of AC Side Connecting Double Thyristors (ACDTS). Aiming at the problem that the current of ACDTS DC side is too large, this paper presents a way to improve the performance by making use of unidirectional thyristor, parallel resistance and inductance. The PSCAD/EMTDC is used to simulate the DC side fault of the improved ACDTS scheme, and compare with the traditional DC line fault and the DC side fault under the ACDTS protection scheme. The simulation results show that the improved ACDTS protection scheme can effectively limit the DC fault current.%为了限制直流配电网中电压源换流器(Voltage Source Converters, VSC)直流侧发生两极短路故障时的直流侧故障电流,研究了其故障发生时的暂态过程,并对交流侧连接双向晶闸管(AC side connecting Double Thyristors, ACDTS)的保护方案进行分析.针对ACDTS直流侧电流过大问题,提出了利用单向晶闸管以及并联电阻电感的方式对其改进.利用 PSCAD/EMTDC 对改进 ACDTS 方案进行直流侧故障仿真,并与传统的直流侧线路故障以及ACDTS保护方案下的直流侧故障相互对比.仿真结果表明,利用改进ACDTS保护方案可以有效地限制直流侧故障电流.