Analyzing the Single-Line to Ground Fault Current Contribution by the Type of Transformer and Distributed Generator

Increasing fault current contribution from Distributed Generation (DG) has become a major concern in power system protection coordination. This paper analyzes the single-line to ground fault (SLGF) current contribution from DG to fault location based on the type of transformer and DG. First of all, sequence network model for different type of transformer and DG is presented to calculate the SLGF current. Then, the fault current calculation method according to DG type is introduced because the system including inverter-based DG is not able to calculate the fault current by the conventional model. Using this model, actual distribution system is used to analyze the SLGF current contribution from DG to fault location when the different combination of transformer and DG is interconnected.