Performance analysis of diode-bridge-type non-superconducting fault current limiter in improving transient stability of DFIG based variable speed wind generator

The application of doubly-fed induction generator (DFIG) is very effective in the fast-growing wind generator (WG) market. The foremost concern for the DFIG based WG system is to maintain the transient stability during fault, as the stator of the DFIG is directly connected to the grid. However, according to the grid code, DFIG needs to remain connected to the network even during the fault. Therefore, transient stability enhancement of the DFIG is very important. In this paper, to achieve this goal a diode-bridge-type nonsuperconductor fault current limiter (NSFCL) is proposed to augment the transient stability of the DFIG based WG system. A three-line-to-ground (3LG), double-line-to-ground (2LG) and single-line-to-ground (1LG) faults were applied to one of the double-circuit transmission lines of the test system to investigate the proposed NSFCL transient stability performance. Besides, a DC resistive superconducting fault current limiter (SFCL), bridge-type fault current limiter (BFCL) and series dynamic braking resistor (SDBR) are also considered to compare their performance with the proposed NSFCL. Simulations were carried out in Matlab/Simulink software. Simulation results show that the NSFCL enhances the transient stability of the DFIG system. Moreover, the NSFCL works better than the DC resistive SFCL, BFCL and SDBR in every aspect.