Fault current limiting in a wind power plant equipped with a DFIG using the interface converter and an optimized located FCL

Along with extending the application of Distributed Generation (DG) units attending renewable energy resources some technical problems such as protection issues are appeared. Fault level increase and inconsistency among protection elements such as relays are of these problems. Fault Current Limiter (FCL) is an appropriate choice that limits the current injected to the faulty point of network by the DG unit and the protection elements coordination is preserved. Wind energy is one of attractive resources to feed DG units and Doubly Fed Induction Generators (DFIGs) are more applied generators used in such DG units.

In this paper a new method is proposed that employs the interface converter of DFIG to limit the fault current injected by the DFIG and two oriented FCLs are used in DC link to limit the current flowing through antiparallel diodes of the converter. The FCL is located in a point of the circuit having the least power. Therefore the FCL is optimized financially rather than other schemes using three-phase FCL. The FCL is used as a complementary instrument along with the converter limiting strategy. The results are obtained from simulation in PSCAD/EMTDC software and they are satisfactory.

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