摘要
柔性直流电网是实现大规模可再生能源发电汇集、输送和并网的有效手段。针对基于混合型MMC的直流故障电流阻断方案会引起功率传输中断的问题,本文提出了一种混合型MMC负压控制与超高速机械开关协调配合的故障电流阻断方法,该方法能够快速阻断故障电流并维持非故障线路的功率传输。通过分析故障电流组成及关键影响因素,确定了换流站的控制目标,基于全桥子模块的电压调节自由度,提出了利用混合型MMC输出负压主动吸收故障电流的控制策略,并设计了其与超高速机械开关的协调配合方案,实现故障的可靠隔离。最后,基于RTLAB实时数字仿真平台搭建了四端柔性直流电网仿真模型,仿真结果表明,本文提出的方法可快速阻断直流故障电流,缩短直流电网功率恢复时间,提高系统安全稳定性。
The flexible DC grid is an effective means to achieve the collection,transmission and grid connection of large-scale renewable energy generation.In view of the power transmission interruption due to DC fault blocking scheme based on hybrid MMC,a kind of fault current blocking method based on hybrid MMC reverse voltage control and ultra-high speed mechanical switch is proposed in this paper.The method can quickly block the fault current and maintain the power transmission of non-fault lines.The control target of converter station is determined by way of analyzing composition of the fault current and the influence of key factor.The control strategy of actively absorbing fault current by using the hybrid MMC output reverse voltage is proposed on the basis of full bridge sub-module voltage regulation of degrees freedom,and its coordination scheme with ultra-high speed mechanical switch is designed so to achieved reliable isolation of fault.Finally,The four terminal flexible DC grid simulation model is set up based on RTLAB real-time digital simulation platform.The simulation results show that the method proposed in this paper can quickly block the DC fault current,shorten the power recovery time of the DC grid and improve safety and stability of the system.
作者
朱博
徐攀腾
王晓雪
辛业春
江守其
ZHU Bo;XU Panteng;WANG Xiaoxue;XIN Yechun;JIANG Shouqi(Guangzhou Bureau of EHV transmission company of China Southern Power Grid Co.,Ltd.,Guangzhou 510663,China;School of Electric Power Engineering,Northeast Electric Power University,Jilin Jilin 132012,China)
出处
《高压电器》
CAS
CSCD
北大核心
2024年第6期148-155,165,共9页
High Voltage Apparatus
基金
国家自然科学基金重点支持项目(U2066208)。
关键词
柔性直流电网
混合型MMC
直流故障
负压控制
DC grid
modular multilevel converter(MMC)
DC fault
reverse voltage control
