Distributed energy resources (DER) impact the load flow and short circuit levels in distribution systems. Therefore, important considerations in order to have a secure DER integration to the electrical systems must be analysed. This integration involves great technical challenges, both to the DERs, as well as to the electrical grid. Potential problems like stressed duties imposed on breakers, out of synchronism reclosing and inadequate selectivity can occur if proper actions are not considered. This paper discusses the general aspects which have to be considered to apply a proper protection setting in systems which operate with distributed energy resources (mainly focused on wind energy and solar energy). The analysis and setting criteria considering adaptive protection to cater for different scenarios of operation, particularly on distribution networks with high levels of flexibility, will be discussed. Proper DER modelling will be included as part of the discussion.