Abstract: In this paper, to more intuitively and effectively analyze the characteristics of power traversal, voltage distribution, and their impact on the safe production of hydropower when chain-structured cascade hydropower stations were connected to the power system, the 'P-S-Z' three-station network in the Dadu River Basin was taken as the research object and the advanced digital power system simulator (ADPSS) integrated function was used for power flow modeling and calculation. Furthermore, their reactive power and voltage simulation analysis was conducted in the multiple scenarios of automatic voltage control (AVC) response. Firstly, starting from the aspects of physical components, network equivalence, parameter settings, etc., a system simulation model was established. Then, according to the different combinations of the power stations put into AVC, various power flow calculation scenarios were set up. Finally, based on the actual operation data, an application example was constructed, and the reactive power and voltage indicators were compared. The simulation results show that the calculation accuracy can reach over 99%, which provides a valuable reference for subsequent research on power grid operation control in areas with abundant hydropower.