Analysis and Enhanced Control of Hybrid-MMC-Based HVDC Systems During Asymmetrical DC Voltage Faults
Analysis and Enhanced Control of Hybrid-MMC-Based HVDC Systems During Asymmetrical DC Voltage Faults
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DOI：
10.1109/tpwrd.2016.2568240
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发表时间：
2017-06
影响因子：
4.4
通讯作者：
Jiabing Hu;Kecheng Xu;Lei Lin;R. Zeng
中科院分区：
文献类型：
--
作者：
Jiabing Hu;Kecheng Xu;Lei Lin;R. Zeng
本文提出了一种增强控制的HVDC系统采用混合模块多电平换流器（MMC）在不对称直流电压故障。分析了系统不同接地方式下的极-地（PTG）故障特征。然后，提出了一种改进的控制策略，以处理PTG故障的混合MMC的高压直流输电系统的对称单极配置的原则。提出了一种新的控制变量的臂电压分配之间的上臂和下臂的交流侧传输的功率。通过采用增强控制，可以在PTG故障发生时消除过电压和故障电流。此外，基于混合MMC的HVDC系统可以通过在故障期间不对称地控制换流器的上下臂而以可调节的有功功率和可控的无功功率连续地运行。最后，通过PSCAD/EMTDC仿真验证了所提控制方案的可行性。
This paper presents an enhanced control for HVDC systems employing hybrid modular multilevel converters (MMCs) during asymmetrical dc voltage faults. The characteristics of pole-to-ground (PTG) fault under different system grounding schemes are analyzed. Then, the principle of enhanced control strategy to deal with the PTG fault is presented for a hybrid-MMC-based HVDC system with symmetrical monopolar configuration. A new control variable is proposed on the arm voltages to distribute the power transmitted from the ac side between the upper and lower arms. By adopting the enhanced control, the overvoltage and the fault current can be eliminated when a PTG fault occurs. Furthermore, the hybrid-MMC-based HVDC system can operate continuously with adjustable active power and controllable reactive power by controlling the upper and lower arms of the converter asymmetrically during a fault period. Finally, the feasibility of the proposed control scheme is verified by simulation results in PSCAD/EMTDC.