MMC-Based VSC-HVDC Link Fault Protection Using Short-Time Fourier Transform

This work presents a protection scheme based on Short-Time Fourier Transform for fault detection in an MMC-based VSC-HVDC system. To perform these tasks only local signals are used and communication links are not required. A robust scheme based on DC current spectrum is evaluated. The proposed method has been tested for different fault locations and resistances in a two-terminal HVDC system with a monopole DC line. The adopted HVDC system was modeled in PSCAD, while the proposed algorithm was developed in Matlab. The results show that the proposed scheme is able to detect faults within a few milliseconds correctly.