Impacts of Distributed Generation on Electric Grid and Selecting of Isolation Transformer

As distributed generation (DG) is increasingly developed, the study of DG has become one of electric power research emphasis. This paper conducts study on impacts of DG on electric grid and how to select isolation transformer. Because of the particularity of DG, interconnection of DG with grid results in a wide range of system issues. One of feasible measurements to reduce the harms is to install isolation transformer at the export of DG units. The general guidelines of selecting transformer are revealed at first, and then the appropriate connection of transformation is brought forward. Besides that, in view of limiting the DG current during the fault of grid and insuring effective grounding of DG, the parameters of DG is chosen based on developing expression and several simulations. The result shows that selecting proper configures and parameters of isolation transformer could be beneficial to the power system with DG units