Active catenary voltage support control for line-side converters in AC trains

Abstract High-power trains are dynamic moving loads in the traction power supply system. When trains move to the end of the traction power supply arm, voltage drop and current phase lag along the catenary are caused by the combined effects of increased line impedance and high-power traction load. The voltage drop along the catenary line may cause overcurrent in the traction drive system, trigger power limitation protection and threaten operation safety. In this paper, a control method for the traction line-side converter with the ability of active catenary voltage support is proposed. First, a coupled dynamic impedance model of the traction power supply system and the traction drive system is established, revealing the causes of voltage drops and the mechanism of catenary voltage support. Then, the active catenary voltage support control is introduced, including the limitations on voltage support capability for safety consideration, the dynamic reactive power regulation method based on the depth of voltage drop and the requirement for strength of system. Finally, both the simulation in MATLAB/Simulink and the experiment on a full-scale test platform verify that the proposed method can quickly respond to catenary voltage drops, and dynamically support catenary voltage, without using extra compensation equipment.