基于控制模式切换的离网换流器无扰并网策略  

Offline Converter Uninterrupted Grid-connected Strategy Based on Control Mode Switching

作　　者：许加柱[1] 张伟明 陈庆 刘洋 XU Jia-zhu;ZHANG Wei-ming;CHEN Qing;LIU Yang(Hunan University,Chongs410000,China;不详)

机构地区：[1]湖南大学电气与信息工程学院,湖南长沙410000 [2]国网江苏省电力有限公司,江苏南京210000 [3]国网江苏省电力有限公司电力科学研究院,江苏南京210000

出　　处：《电力电子技术》2019年第12期63-65,70,共4页Power Electronics

基　　金：国家重点研发计划(2018YFB0904700)~~

摘　　要：中低压直流配电网发生故障时,为保护并网换流器,常采用离网保护控制策略;当离网换流器再并网恢复时,若不采用有效的并网控制策略,易对系统产生扰动而诱发二次故障。针对该问题,提出了一种基于控制模式切换的离网换流器无扰并网策略,首先分析了离网换流器并网扰动的产生机理,并基于交直流配电电能质量标准定义了离网换流器无扰并网的评价指标;其次,给出了换流器的控制方程,分析了换流器采用整流和逆变两种并网方式的无扰并网策略;最后,以某一实际两端型中低压直流配电网为例,结合无扰并网指标,仿真对比了两种并网控制策略的并网性能。结果表明:整流方式的无扰并网控制策略性能更优,为离网换流器的无扰并网提供了理论支撑。When a fault occurs in the medium-low voltage DC distribution network,the off-grid protection control strategy is often used to protect the grid-connected converter.When the offline converter is re-connected to the grid without the effective grid-connected control strategy,system is more prone to being disturbed and thus lead to secondary fault.An offline converter uninterrupted grid-connected strategy based on control mode switching is proposed.Firstly,the generation mechanism of grid-connected disturbance of the offline converter is analyzed,and the uninterrupted grid-connected evaluation index of the offline converter is defined based on the AC/DC power quality standard.Secondly,the control equation of the converter is given,the uninterrupted grid-connected strategy is analyzed in the mode of rectification and inversion.Finally,taking an actual two-terminal medium-low voltage DC distribution network as an example,which combined with the uninterrupted grid-connected evaluation index,the grid-connected performance of the two grid-connected control strategies is compared by simulation.The results show that the performance of the uninterrupted grid-connected strategy is better with rectifying mode,providing theoretical support for the uninterrupted grid connection of the offline converter.

关 键 词：换流器 整流方式 并网控制策略 电能质量标准 离网 并网方式 直流配电 并网策略 

分 类 号：TM46[电气工程—电器]