Effect of Transformer connections in Distributed Generation system

Nowadays protection with transformers in DG units embedded to utility has been topic of research, transformers not only transfers power with constant frequency; it also plays a remarkable role in protection as well. The integration of “Distributed generation” units (DG)into distribution system can be complete through power conditioning units (PCU), transformers and protective devices. Though protection devices are essential to give protection andalter their capacity as per the high penetrationof DG's. This paper discussed aboutdistributed generation units interfaced to utility with different transformer connectionslike Delta/Delta, Delta/Star grounded, Star grounded/Delta, Star grounded/Star grounded. It investigates how this transformer connections shows impact on protection. For this different DG units are designed, interfaced and tested with different transformer connections. In proposed approachStar grounded/Star grounded configuration describe optimalpower variations during the faultsand it is recommended to protection applications of cogeneration integration to utility. Simulations have been performed in MATLAB Simulink Software.