Research on Automatic Voltage Control for Chain-structured Hydropower Stations

Automatic Voltage Control (AVC) of the power system is one of the reactive-voltage control measures. Reasonable arrangement of various control means and selection of feasible control strategies can improve the voltage quality, reduce network loss and stabilize reserve. Firstly, with the system architecture, operation mode, AVC condition, and power flow of the chain-structured hydropower, the paper analyzes the reactive power and voltage operation during AVC and the reactive power pulling problem of reactive power between stations, which is concluded that the difficulty of reactive power and voltage regulation of chain-structured hydropower lies in the multi-level regulation objectives, the coordinated regulation, and the lack of effective regulation strategy guidance. Then, the methods of voltage-reactive power regional control to solve the AVC regulation problem for chain-structured hydropower stations are proposed and discussed based on the Regional Voltage Control System (RVCS) model. Finally, a voltage joint regulation model of three-station chain-structured hydropower is established for simulation. The results show that the RVCS strategy has a mitigation and correction effect on the reactive power pull phenomenon and voltage deviation problem during AVC regulation, which is of great significance to ensure the safe and economic operation of the system.