Dynamic equivalents of active distribution power systems for investigation of transient stability

In Norway distribution networks are evolving rapidly into active systems due to the increasing number of connections of small scale hydro generation units. As most of the distributed generation is based on synchronous technology their dynamic response on the bulk transmission power system cannot longer be neglected. In this paper a method for power systems reduction and aggregation of generators is applied to obtain dynamic equivalents of distribution power systems with DG units. Criteria to validate this method for distribution power systems are proposed.