Flexible Arc Suppression Method Using Cascaded H-Bridge Converters With Adaptive Voltage Drop Compensation

The traditional current-type flexible arc suppression method fails to account for the impact of line voltage drop, resulting in residual current during grounding fault suppression. To improve fault current suppression performance, this article proposes flexible arc suppression method using cascaded H-bridge converters with adaptive voltage drop compensation. First, the theoretical expression for a novel injection current arc suppression algorithm is derived, incorporating the effects of line voltage drop. Subsequently, the differences between the newly developed algorithm and the original algorithm for zero-sequence voltage regulation are analyzed. Building on these differences, an injection current arc suppression algorithm with adaptive line voltage drop is constructed, enabling the realization of zero residual currents under varying ground fault conditions. Furthermore, to address the impact of variations in the equivalent load impedance of the cascaded H-bridge converter on the stability of the control system, this article proposes a controller design method that considers changes in grounding fault parameters, ensuring stable current output from the cascaded H-bridge converters. Finally, the correctness and feasibility of the proposed method are validated through PSCAD/EMTDC simulations and physical experiments.