An adaptive control strategy of converter based DG to maintain protection coordination in distribution system

Distributed generation (DG) is increasingly integrated into distribution systems due to its flexible onsite characteristic and low carbon emission. However, DG integration may change the fault current pattern in distribution systems, which may in turn degrade the performance and coordination of network protection devices. As a protection measure commonly used in distribution network, recloser-fuse coordination could suffer from this impact. Research work has been conducted to deal with this problem by modifying the control strategy of the DG converters during faults. These solutions generally reduce the current output from the converters during faults so as to mitigate the influence on protection coordination. However, converter current reduction may not be necessary for all types of faults. This paper proposes a converter control strategy with adaptivity to different fault types and also non-fault voltage drop events. This control strategy is validated by simulations in DIgSILENT PowerFactory.