Source type impact of distributed generation (DG) on the distribution protection

The protection system design in common MV and LV distribution networks is determined by a passive paradigm, i.e. no generation is expected in the network. With distributed sources, the networks get active and conventional protection turns out to be unsuitable. In most cases, the issue is investigated with synchronous generators, while other generator types like Doubly Fed Induction Generators (DFIG) or induction generators are also available. The capability of the generators of DG systems to feed the fault during disturbances would affect the results considerably. In this paper, the important issues such as the ones mentioned above are analyzed with different types of DG generators, and the results are compared to highlight the impact of different DG types on the specified issues. This study is useful from the utilities' point of view, since it is not necessary to attract their attention to the extreme conditions. Sometimes, the type of the DG sources is so, that their contribution to the fault level is negligible and can be ignored, while in some cases the impact of another type of generator for DG is not negligible.