Cascaded H-Bridge Converter-Based Flexible Arc Suppression Method Adapting to Line Parameter Variations

Single-phase grounding faults in distribution networks can generate arcs, posing significant risks such as electric shock and forest fires. The flexible arc suppression device (FASD) is capable of suppressing the arc. However, traditional FASDs do not account for line voltage drop and asymmetry in ground parameters when calculating the injection current reference value. Consequently, changes in ground fault conditions can impair the effectiveness of zero residual current suppression, undermining the reliability of arc suppression. To address this issue, this article proposes a flexible arc suppression method that adapts to line parameter variations. This article provides a theoretical analysis of the differences between the newly deduced arc suppression algorithm and the original algorithm, with a focus on zero-sequence voltage regulation and ground fault current suppression. The analysis elucidates the law of parameter variations governing the dominant zero-sequence voltage difference after regulation. Subsequently, an adaptive injection current arc suppression algorithm is proposed based on this law, which accommodates changes in line parameters. Compared to traditional methods, the proposed algorithm demonstrates enhanced adaptability to variations in grounding fault parameters and significantly improves current suppression effectiveness. The correctness and feasibility of the method are validated through PSCAD/EMTDC simulations and physical experiments.