Cascaded Grid-Connected Converter Coupled with Peterson Coil for Harmonic Compensation and Arc Suppression in Distribution Networks

The complicated operating conditions of distribution networks may be prone to single-phase grounding (SPG) fault. Based on statistics, SPG faults account for more than 80% of all fault types in the distribution networks. Arc suppression coil can typically compensate for most of the capacitive fault current but cannot eliminate the fault voltage, and the residual fault current, including the active current, is still high. To limit fault current completely and eliminate voltage simultaneously, a cascaded grid-connected converter (CGCC) coupled with an arc suppression coil is presented in this paper. However, with the increase of nonlinear loads, the transmission lines contain a large amount of harmonic current. Thus, the CGCC is proposed to compensate the harmonic current simultaneously by controlling its d-axis and q-axis output components, and to control the 0-axis output component for arc suppression, and the controls of harmonic compensation and arc suppression are decoupled, so that the utilization and cost-effectiveness are improved.