Research on Voltage Command Optimization Strategy of Chain-Circuit STATCOM

In this paper, the transient voltage control method of cascaded STATCOM is studied, and the response characteristics under three-phase grounding short-circuit fault are analyzed, including bus voltage, DC system and control module under the condition of constant voltage command of STATCOM. Aiming at the problem in STATCOM transient voltage control that constant voltage command may be result in the voltage steady-state value deviation of converter station after short-circuit fault, a voltage command optimization method is proposed based on system state variables to change the transient voltage command value in real time in this paper. The simulation result shows that by adding voltage command optimization control, the voltage difference is not obvious and the effective value of the converter bus voltage basically the same pre-and post when occurred three-phase grounding transient fault.