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The distribution network reliability can be increased if distributed generators (DGs) are allowed to operate in both grid-connected and islanded operations when the network has a high DG penetration level. However, the current utility regulations do not allow for the islanded operation. The arc faults are the one of the major issues preventing the islanded operation, since the arc will not extinguish if the DGs are not disconnected. In this paper, the effect of a converter interfaced DG on an arc fault is investigated by considering different control strategies for the converter. The foldback current control characteristic is proposed to a converter interfaced DG to achieve quick arc extinction and self-restoration without disconnecting the DG in the event of an arc fault. The results are validated through PSCAD/EMTDC simulations.

Distance relay response in the presence of a converter dominated microgrid system has been analyzed in this paper. Converter structure and control mechanism are presented and a new method is proposed to limit fault currents in faulted phase/phases by reducing the converter output voltage. A method of analyzing unsymmetrical supply voltage using symmetrical component theory is proposed, where it has been assumed that voltage source converter (VSC) supplies unbalanced voltages in the event of a fault. Performance of distance relays with Mho characteristics are evaluated in a radial distribution feeder for both phase and earth unbalanced faults. The results are validated through PSCAD simulation and MATLAB calculations