Research of Stability Control Strategy at the Sending End of UHVDC After Block Fault

Block fault of ultra-high-voltage direct current (UHVDC) for large-scale renewable energy long distance transmission will have a significant impact on sending end power grid. To study the stability control strategy at the sending end power grid, firstly, characteristics of sending end power grid and the impact of start-up mode of bundled thermal power on transient voltage after the block fault of UHVDC are studied using Hami-Zhengzhou UHVDC as an example. Secondly, a thorough analysis of the effects of different AC filters removal schemes in converter stations and types of shutting-off generators on transient voltage rise is presented, and the control time coordination issue of these two types of controls is studied as well. Finally, principles and methods for decision-making of stability control strategy for UHVDC block fault are proposed, which could provide valuable reference for follow-up studies on UHVDC.