摘要
柔性互联模块化多电平高压直流输电(modular multilevel converter based high voltage direct current,MMC-HVDC)系统规模庞大且内部动态复杂,同时控制通信回路的信息时滞增大了系统发生次同步振荡的风险。因此,需要建立高效、简洁的模块化信息物理系统模型来分析混合系统稳定性与次同步振荡现象的影响。针对MMC-HVDC系统拓扑多变的特点,文中借助模块化建模思路构建柔性互联MMC-HVDC信息-物理模型。为了探究系统振荡的根本原因,建立两阶段振荡分析框架。利用Rekasius变换实现快速的稳定域与振荡频率求解。根据关键模态,进一步应用通用Pade逼近生成包含系统动态和时滞动态的升阶模型,并引入参与因子法分析了次同步振荡的内在原因,探究次同步振荡的影响因素和时滞诱发次同步振荡、高频振荡两类振荡的区别。整个模块化建模过程、两阶段振荡分析框架、振荡模态利用Simulink的仿真波形和快速傅里叶变换谐波分析进行全面验证。结果揭示了信息时滞既可以诱发次同步振荡也可以引起高频振荡,但二者原理不同。次同步振荡由桥臂电感电容的能量互动引起,环流占主导作用,调整电容或环流控制系数可以有效抑制振荡。
The flexible interconnection modular multilevel converter based high voltage direct current(MMC-HVDC)system is large in scale and has complex internal dynamics.Meanwhile, the information delays introduced by the control loops and communication networks increase the risk of subsynchronous oscillation(SSO). Therefore, it’s necessary to build the modular cyber-physical system model which is efficient and concise to analyze the hybrid system stability and the effect of the SSO. For the characteristics of the MMC-HVDC system’s topology diversity, the modular modeling design was used to build the flexible interconnection MMC-HVDC system cyber-physical model. To investigate the root cause of the oscillation, the two-stage oscillation analysis framework was established. And the Rekasius substitution for multiple delays was deployed to solve the stability region and oscillation frequency efficiently in the first stage. Moreover,according to the oscillation mode, a unified Pade approximation form for multiple delays was applied to generate the increased-order model containing the system dynamics and delay dynamics. The intrinsic cause of the SSO was analyzed using the participation factor method. This paper revealed the influence factors of the SSO and the differences between two types of oscillations: the SSO and the high-frequency oscillation. The time-domain responses and fast Fourier transform(FFT) harmonics analysis in Simulink were tested to validate the whole modular modeling procedure, the two-stage oscillation analysis framework and the oscillation mode. The results show that the delay may cause the SSO or the high-frequency oscillation based on different principles. The SSO is triggered by the energy interaction between the arm inductance and the submodule capacitance. The circulating current plays a dominant role in the SSO and the adjustment of the capacitance or the circulating current suppressing controller coefficients can help to suppress the oscillation.
作者
曹靖洺
董朝宇
穆云飞
余晓丹
肖迁
贾宏杰
CAO Jingming;DONG Chaoyu;MU Yunfei;YU Xiaodan;XIAO Qian;JIA Hongjie(Key Laboratory of Smart Grid of Ministry of Education(Tianjin University),Nankai District,Tianjin 300072,China)
出处
《中国电机工程学报》
EI
CSCD
北大核心
2022年第24期8803-8815,共13页
Proceedings of the CSEE
基金
国家自然科学基金项目(51625702,U1766210)。
