Abstract—With the rapid development of the global economics, it is an inevitable trend for power grid development to adopt long-distance and large-capacity AC-DC parallel transmission. During the initial stage of power system interconnection, the security, stability and emergency control of AC weakly interconnected power transmission paths are affected by large-capacity DC blocking to a certain extent. Through constructing the typical operating modes of AC-DC hybrid grid, this paper analyzes the AC-DC coupling effects and the characteristics of imbalance power allocation under the occurrence of large-capacity DC blocking, and further studies the impacts of interconnection of power grids on the security, stability and emergency control of AC interconnected power transmission paths under the occurrence of large-capacity DC blocking and elaborates the necessity of strengthening the coordinative development of AC-DC systems in the process of AC-DC interconnection of power grids, which provides the technical support for the planning, construction, and secure and stable operation of the interconnection of power grids.

Index Terms—AC-DC interaction, imbalance power, coupling, weak interconnection, security and stability.

Haijun Chang, Xiancheng Ren, Wei Li, and Zhaojun Meng are with China Electric Power Research Institute, Nanjing, 210003 China (e-mail: changhaijun@epri.sgcc.com.cn, renxiancheng@epri.sgcc.com.cn, liwei@epri.sgcc.com.cn, mengzhaojun@epri.sgcc.com.cn).
Jie Dang, Youping Xu, and Jianghui Xi are with Central China Power System Dispatching & Control Branch Center, Wuhan, 430077 China(e-mail: dangj@cc.sgcc.com.cn, xuyp@cc.sgcc.com.cn, xijh@cc.sgcc.com.cn)