Transient Stability Enhancement of a Synchronous Generator Using DFIG Considering its LVRT Capability

The high penetration of doubly fed induction generators (DFIGs) to the grid may affect the stability of the synchronous generators (SGs). The dedicated control of the DFIG can enhance the transient stability of the SG. This paper proposes a transient control technique for DFIG, which enhances the rotor angle stability of the SG. The proposed control technique operates the DFIG in motoring mode during a fault, by modulating the electromagnetic torque considering the PCC bus voltage and low voltage ride-through (LVRT) capability of DFIG. In order to appropriately realize the practical behavior of the DFIG under a fault scenario, the standard LVRT capability of the DFIG is also incorporated along with the proposed technique. To avoid the post-fault instability of the system, a rate limiter is used to allow the smooth recovery of the DFIG. The real time digital simulator (RTDS) is used to analyze the performance of the proposed technique in a modified IEEE 9-bus system.