A Fast Fault Detection for Multi-Terminal VSC HVDC Transmission Lines

The quick rise of DC short circuit current becomes a great challenge in high voltage direct current (HVDC) systems. The protection system issues of HVDC have been increasing with the presence of multi-terminal (MT) HVDC systems, in particular meshed ones. This paper proposes a fast DC fault detection scheme for MT-HVDC systems. The proposed method can detect faulted lines using only DC inductors. Moreover, this method uses the variations of inductor voltage in transmission lines (TLs) without telecommunication and it is robust against high impedance faults (HIFs). Fast Fourier transform (FFT) is considered to detect the faulted line and HIF. The case study is simulated using the PSCAD/EMTDC software to evaluate the performance of the proposed method with pole-to-pole and pole-to-ground faults. The results confirm the accuracy of the proposed method.