虚拟同步发电机控制下多端交直流混联电力系统间的强动态交互过程及其传播
Strong Dynamic Interaction and Propagation of Multi-terminal AC/DC Hybrid Power System with Virtual Synchronous Generator Control
-
摘要: 该文针对虚拟同步发电机(virtualsynchronous generator,VSG)控制下的多端交直流混联电力系统,首先建立了VSG控制子系统作为反馈环节的交直流混联系统闭环线性化互联模型,分析强动态交互过程的产生条件,论证其对稳定性的负面影响,提出混联电力系统在强动态交互过程下的稳定性判据。然后,研究上述强动态交互过程的传播路径,得出VSG控制子系统与剩余子系统间强动态交互过程的传播路径包含直流线路和交流线路两部分,其中直流系统的下垂控制参数会对强动态交互过程的传播产生显著影响。因此,提出通过断开交流线路、采用较小的下垂系数来阻断、抑制强动态交互过程的传播,并通过设定合理的VSG控制参数进一步破坏其产生的条件,避免由于VSG接入引起的强动态交互过程及其对稳定性的潜在威胁,提升VSG控制下多端交直流混联电力系统的稳定性。最后,在VSG控制的三端交直流混联电力系统算例中,采用模式分析法和时域仿真法验证上述分析结果。Abstract: Strong dynamic interaction and propagation of multi-terminal AC/DC hybrid power system with virtual synchronous generator control were analyzed in this paper. Firstly, the closed-loop interconnected linearization model of AC/DC hybrid power system which virtual synchronous generator（VSG） control subsystem taken as a feedback loop was established, the strong dynamic and its impact on stability of power system was researched and the stability criterion under strong dynamic was presented. Then, the propagation of strong dynamic, which is influenced significantly by droop control coefficient, was studied and concluded that the propagation path contains DC and AC lines. Based on the above analysis, the methods of avoiding the strong dynamic and improving the stability of hybrid power system were given as: break AC lines, use small droop control coefficient and set reasonable VSG control parameters. Finally, the time domain simulation and modal analysis were carried out and verified the above results based on a three terminal AC/DC hybrid power system with VSG.
下载:
