Influence of Capacitor Voltage Transformer's Transient Response on Commutation of HVDC Transmission System

The capacitor voltage transformer (CVT) has a transient response when a fault occurs on the inverter side of HVDC. The output voltage at the secondary side of CVT can not accurately reflect the change of the input voltage at the primary side in time, which will affect the commutation process of the DC system. This paper first establishes a simulation model in PSCAD/EMTDC with the actual parameters of the 220kV saturated CVT, and analyzes the effects of different factors on the transient process. The principle of commutation failure predictive control (CFPREV) is analyzed, and its input voltage has an impact on the commutation process of the DC system. Based on the simulation of East China Power Grid Ge Nan DC model, the AC voltage considering the CVT transient response is used as the input voltage for CFPREV, and the CFPREV link and commutation process are analyzed.