Abstract: The small renewable resources is becoming one of the major systems to generate electricity in distribution generation systems to feed electrical loads. Fault current level has become a major problem in distribution system operations. The effect of short circuit current and induced over voltages under abnormal conditions should be avoided for reliable operation .That abnormal conditions effect can be limited by applying an active type Super conducting Fault Current Limiter (SFCL) in distribution system. Effects of a voltage compensation type active SFCL on that abnormal conditions are studied through theoretical derivation and simulation. The active SFCL mainly consists of an air-core superconducting transformer and converter. During the study process, by changing the locations of the DG units and the fault locations, the current-limiting and overvoltage suppressing characteristics by active SFCL are simulated in MATLAB /SIMULINK. The simulation results show that the active SFCL can regulate the fault current and overvoltage in the presence of distributed generation, and it can nullify the damage of the distribution equipment and improve the system reliability and safety.

Keywords: overvoltage suppressing, fault circuit current limitation, active SFCL (Superconducting Fault Current Limiter) and Distributed Generation.