A new method to eliminate DG´s negative effects on the existing distribution network protection

Distributed Generation (DG) will affect the amperage, direction and distribution of fault current. With the penetration of DG, the existing protection and automatic devices may not operate correctly. In accordance with how DG affects the protection of distribution system, the importance of connecting a fault current limiter (FCL) to DG to restrict the fault current is analyzed, and the detailed algorithm to get the parameters of FCL is presented with a case. In the end, through the simulation by Matlab/EMTP we proved that FCL with properly selected parameters can effectively restrict DG´s fault current, eliminate DG´s negative effects and guarantee the original protection´s reliability and selectivity. In addition, We can also add direction protection to solve the problem of DG´s backward fault current if necessary.