Flexible arc-suppression method based on improved distributed commutations modulation for distribution networks

Abstract Because of the hazard of single-phase-to-ground faults on distribution networks for human security and device insulation, it is important for the ground-fault current to be eliminated by an arc-suppression device. However, owing to their shortcomings, passive arc-suppression devices cannot compensate the ground-fault current fully. Therefore, active arc-suppression devices have been studied. The flexible arc-suppression device (FASD) with a cascaded H-bridge (HB) topology is one type of active arc-suppression device. An FASD connected to a bus bar of distribution networks is applied to mitigate the ground-fault current. Owing to the high voltage and large current during the ground fault, a large number of HBs are required for the FASD. To modulate the HBs, an improved distributed commutations modulation method, which is combined with the flexible arc-suppression method, is proposed. The proposed modulation strategy aims to minimise the error between the reference signal and the tracking signal during each sampling period. Finally, the proposed strategy is validated via simulations and experiments to confirm its effectiveness for the FASD.