The application of inverter-based distributed generators (DGs) in the distribution network has made the conventional short-circuit current calculation method of the distribution network no longer applicable. According to DG locations in the distribution network

the DGs are treated as different types of fault equivalent model. The DGs connected upstream are modeled as the low voltage ride through (LVRT) fault equivalent model while those connected downstream the constant-current-source fault equivalent model. Then an iterative short-circuit current calculating method based on the superposition theorem is proposed. In each iterative procedure

the short-circuit current outputs from the DGs are modified according to the current bus voltage and the corresponding fault equivalent model of DGs. And the bus voltage equation is used to calculate the short-circuit current and bus voltage distribution until the convergent conditions are met. Finally

the calculation results concerning the test systems show that the proposed method is effective and accurate. The method can be applied to short-circuit current calculation in large-scale distribution network with DGs. This work is supported by National Natural Science Foundation of China (No. 51507139)

Shaanxi Provincial Specialized Fund for Key Discipline Developmemt (No. 5X1301)

and Specialized Research Fund for the Doctoral Program of Higher Education (SRFDP) of China (No. 20126118110009)