Contribution of induction-machine distributed generators to fault current and assessing their impact on overcurrent protection

Distributed Generators (DGs) provide a number of advantages for utilities. So, they become very common these days. However, DGs can also negatively impact some aspects of distribution system such as Overcurrent (O.C.) protection. DGs are known to contribute fault currents to their interconnected power system. As a result, there is a concern that the DGs may affect the coordination of O.C. protection in a distribution system. This may cause miscoordination among O.C. devices, nuisance tripping and relay´s reach reduction (desensitization). This paper presents the findings on the contributions of a certain type of DGs, Induction-Machine DG (IMDG), to fault currents and assessing its impacts on the O.C. protection coordination.