关键词: 直流多落点系统, 多馈入短路比, 复功率短路比, 多落点交互作用因子

Abstract: The HVDC multi-feed systems have been formed in South China Power Grid, East China power grid and Sichuan power grid. The existing multi-infeed interaction factor (MIIF) and multi-infeed short circuit ratio (MSCR), however, do not consider the interactions of converter stations in the AC-DC hybrid transmission system and the reactive losses of converter stations. With consideration of the interactions of all converter stations and their reactive loss in form of complex power, the complex power multi-feed short circuit ratio(CMSCR) is proposed in this paper through extending the existing MIIF and MSCR to the AC/DC parallel multi-feed systems. It is proved that the strength of grid system is not only related to the power grid’s structural parameters and DC power variations, but also affected by the bus voltage of the converters. Simulation case study indicates that the CMSCR can characterize, to some extent, the anti-voltage drop capability of the converter buses and is more suitable for practical studies. Moreover, it can offset the deficiency of existing short circuit ratio(SCR) for not considering the reactive influences which often lead to over optimistic evaluation results, and is helpful for AC-DC interconnected power grid stability analysis and planning.

Key words: HVDC multi-feed system, multi-infeed short circuit ratio, complex power multi-feed short circuit ratio, multi-infeed interaction factor