A review on the dynamic analysis of weak distribution networks

During the last years, the increased penetration of distributed generation (DG) has started to affect also the transmission system. The increasing presence of weak networks, together with unpredictable power produced by the DG units, has a considerable impact on the behaviour of the whole power system, starting from the DG units and passing to distribution/transmission levels. Voltage control, frequency control and stability issues of the network are changing considerably due to the presence of DG. In particular, the problems appear at the connection of DG units with the distribution network. This paper presents several aspects regarding the connection problems between low inertia DG's and the electrical grid, reviewing the state-of-the-art with the objective of identifying the main concepts and operational aspects referring to dynamic analysis.