A Novel Scheme of HVDC Transmission Line Voltage Traveling Wave Protection Based on Wavelet Transform

At present, traveling wave protection´s reliability of HVDC transmission line in projects is not satisfying. Therefore, the thesis analyzes amply direct line transient characters after faults occur including line inside and out, fault lightening stroke and non-fault lightening stroke, line earthing with large resistance and noise interference. Use wavelet multi-resolution signal decomposition technique to analyze the various transient voltages traveling wave, and calculate their energy distribution, finally find their own transient voltages energy distribution characters on different frequency, which exist some intersectant sections and also have unique part. Based on these characters, the thesis gives an excellent performance protection criterion. The thesis makes simulations for various faults using electromagnetism emluator PSCAD/EMTDC. A great deal of simulations indicate that this traveling wave protection has a good anti-jamming capability and ascendant action performance.