Protection Wavelet Transform and energy spectrum analysis based HVDC transmission

The present invention discloses a method for protecting high-voltage direct current wavelet transform and spectral analysis of the energy transmission line based on the criterion by starting voltage fluctuation constitutes the set threshold value, since the non-fault to prevent the system voltage fluctuations caused by frequent start protection device, and possible to reliably start the DC transmission line fault; fault voltage using traveling wave wavelet transform modulus maxima polarity after comparison method, the inner and outer partition zone fault; using transient voltage energy distribution within different frequency bands, the failure to distinguish between interference and lightning , while identification of a bipolar electrode system failure sound pole.