Due to the operation of Chongqing-Hubei back-to-back flexible DC and central Tibet-Changdu networking project

the scale of Southwest China synchronous power grid is significantly reduced

and the long chain-weak interconnection structure is outstanding. The characteristics of power grid security and stability face profound changes. Based on the in-depth analysis of the operation characteristics and risks of Southwest China power grid

the weakness and shortcomings of existing security and stability control strategies are analyzed. The architecture and function configuration scheme of system protection are proposed to meet the demand of differential stability control for the Southwest China power grid

and its key technologies are expounded. The system realizes power-angle stability control in the whole grid

frequency control

voltage control

suppression of low frequency oscillation and ultra-low frequency oscillation and panoramic state sensing and monitoring

which improves the transmission capability of large-scale hydropower in Southwest China power grid

and ensures the safe and stable operation of the Southwest China power grid and even the national power grid.