Installation of Distributed Energy Resources (DER) in the distribution networks is a common challenge for European states and means change of operation and technical conditions for the distribution networks. Stability phenomena may be dangerous and angle stability of DER-synchronous generators should be considered. DER stability is influenced by a number of factors some of them are very specific. Impact of selected factors is studied based on simulations. Obtained results show that installation of DER in the distribution network should be done carefully with a range of preliminary simulations. Some special actions may be required to manage DER stability problem.