Background: A novel fault location method of HVDC transmission line based on a concentric
relaxation principle is proposed in this paper.
Methods: Due to the different position of fault, the instantaneous energy measured from rectifier
and inverter are different, and the ratio k between them is the relationship to the fault location d.
Through the analysis of amplitude-frequency characteristics, we found that the wave attenuation
characteristic of low frequency in the traveling wave is stable, and the amplitude of energy is larger,
so we get the instantaneous energy ratio by using the low-frequency data. By using the method of
wavelet packet decomposition, the voltage traveling wave signal was decomposed.
Results: Finally, calculate the value k. By using the data fitting, the relative function of k and d can
be got, that is the fault location function.
Conclusion: After an exhaustive evaluation process considering different fault locations, fault resistances,
and noise on the unipolar DC transmission system, four-machine two-area AC/DC parallel
system, and an actual complex grid, the method presented here showed a very accurate and robust