Research On Transient Voltage Regulation Control Strategy Of Hybrid Doubly-fed DC Power Transmission System

In order to provide voltage support to the AC system at the receiving end by relying on the continuously adjustable capability of VSC active and reactive power when the hybrid doubly-fed DC transmission system fails, based on analyzing the failure mechanism of continuous commutation of LCC, the reactive power characteristics of ac fault on the inverter side and the characteristics of constant AC voltage, A VSC additional transient voltage regulation control strategy module based on AC voltage change rate control is designed. According to the voltage change rate of the bus when the fault occurs, the strategy can improve the characteristics of the AC transient voltage by suppressing the transient low voltage module and suppressing the transient overvoltage module with additional compensating voltage value. Finally, based on PSCAD/EMTDC, a simulation model of the hybrid doubly-fed HVDC system is established, and the simulation results under different AC faults with different duration are compared and analyzed, which verifies the superiority of the proposed control strategy compared with the constant AC voltage control.