摘要
随着电力系统中新能源接入比例不断提高,采用跟网控制的模块化多电平换流器型柔性直流输电(Modular multilevel converter based high voltage direct current,MMC-HVDC)在输电系统中占据越来越重要的地位,其并网暂态同步稳定性会影响电力系统的安全运行。研究跟网型MMC-HVDC系统的暂态同步稳定机理,首先建立了以锁相环为同步单元的换流器的并网动力学模型,随后基于此模型,研究了电网强度、换流器的故障穿越策略以及锁相环参数对其暂态稳定性的影响。当电网强度较高、换流器故障期间注入无功电流分量增大时,换流器的并网暂态稳定性较强,减小锁相环的比例和积分增益有利于暂态稳定性。根据暂态稳定机理,提出了与阻抗角匹配的故障期间注入电流策略,以提升换流器的暂态同步稳定性。在时域仿真软件PSCAD/EMTDC中搭建了电磁暂态仿真模型并验证了本文结论和所提暂态稳定增强策略的有效性。
With the increase of renewable power integration,the modular multilevel converter based high voltage direct current(MMC-HVDC)with grid-following control has gained more importance in the transmission system.The transient stability of MMC-HVDC will affect the secure operation of power system.The transient stability mechanism of grid-following MMC-HVDC is studied.The dynamic model of phase-locked loop(PLL)is developed first.Firstly,the grid-connected dynamic model of MMC with phase-locked loop(PLL)as synchronization unit is established.Then based on the model,the influence of grid strength,fault-ride through control and PLL parameters on the transient stability is studied.The grid-connected transient stability of the MMC enhances when the power grid strength is high and the reactive component of injection current during the fault increases.Reducing the proportion and integral gain of the PLL is beneficial to transient stability.According to the stability mechanism,a control strategy of injection current is proposed for the MMC to improve the transient stability by matching the current angle with the grid impedance angle.The time-domain simulation in PSCAD/EMTDC verified the conclusions and the effectiveness of the proposed enhancement control.
作者
项中明
倪秋龙
李振华
徐建平
薛翼程
张哲任
徐政
XIANG Zhongming;NI Qiulong;LI Zhenhua;XU Jianping;XUE Yicheng;ZHANG Zheren;XU Zheng(State Grid Zhejiang Electric Power Corporation,Hangzhou 310007;Jinhua Power Supply Corporation,State Grid Zhejiang Electric Power Corporation,Jinhua 321017;College of Electrical Engineering,Zhejiang University,Hangzhou 310027)
出处
《电气工程学报》
CSCD
2023年第3期250-259,共10页
Journal of Electrical Engineering
基金
国网浙江省电力有限公司科技资助项目(5211JH2000RW)。
关键词
模块化多电平换流器
暂态稳定性
锁相环
故障穿越策略
Modular multilevel converter
transient stability
phase-locked loop
fault ride-through control strategy
