NFTSMC-Based Approach for Mitigating SSR in a DFIG-Based WECS

Accommodating the penetration of high levels of wind energy into the existing grid have led to heavily series compensated transmission lines. These heavily compensated lines, however, result in sub-synchronous resonance (SSR) in the network, which in turn creates a negative equivalent resistance in the Doubly-fed Induction Generator (DFIG) system. This results in severe, sustained, and resonating oscillations in the DFIG dynamics, which can damage the DFIG system if not properly mitigated. In this paper, a non-singular fast terminal sliding mode control-based (NFTSMC) approach is proposed for a DFIG-based wind energy system. The proposed approach combines the fast convergence and robustness of the NFTSMC with the fast current support capability of the superconducting magnetic energy storage (SMES) to provide necessary current support for mitigating SSR. The proposed approach is aimed at effectively mitigating the SSR from effectively regulated current support of the SMES. The proposed control approach is validated in IEEE first benchmark model.