Fault ride through capability enhancement of a large-scale PMSG wind system with bridge type fault current limiters

In this paper, bridge type fault current limiter (BFCL) is proposed as a potential solution to the fault problems of permanent magnet synchronous generator (PMSG) based large-scale wind energy system. As PMSG wind system is more vulnerable to disturbances, it is essential to guarantee the stability during severe disturbances by enhancing the fault ride through capability. BFCL controller has been designed to insert resistance and inductance during the inception of system disturbances in order to limit fault current. Constant capacitor voltage has been maintained by the grid voltage source converter (GVSC) controller while current extraction or injection has been achieved by machine VSC (MVSC) controller. Symmetrical and unsymmetrical faults have been applied in the system to show the effectiveness of the proposed BFCL solution. PMSG wind system, BFCL and their controllers have been implemented by real time hardware in loop (RTHIL) setup with real time digital simulator (RTDS) and dSPACE. Another significant feature of this work is that the performance of the proposed BFCL is compared with that of series dynamic braking resistor (SDBR). Comparative RTHIL implementation results show that the proposed BFCL is very efficient in improving system fault ride through capability by limiting the fault current and outperforms SDBR.