Abstract:
In order to properly evaluate the voltage support capability of the multi-infeed HVDC (MIDC) system with high proportion of new energy access, this paper first analyzes the structural characteristics of the MIDC system, and based on the multi-infeed short circuit ratio (MISCR) index and the characteristics of the amplitude and phase variation of the short-circuit current (hereinafter referred to as "amplitude and phase characteristics") caused by new energy, a new index called multi-infeed transient short circuit ratio (
MITSCR) is proposed. Then, adhering to the requirements stipulated in the National Standard of the People's Republic of China, the amplitude and phase characteristics of new energy represented by doubly-fed induction generators (DFIG) under different control modes are analyzed, and the impact of DFIG access on the node's voltage support capability of the MIDC system is also analyzed through the MITSCR index. Finally, time-domain simulation analysis is carried out using the PSACD/EMTDC software, and the results show that the MITSCR index can effectively characterize the node's voltage support capability, verifying the effectiveness and superiority of the index.