Research Of High Voltage Transmission Line Fault Diagnosis Based On Hilbert-huang Transform

With the continuous improvement of transmission capacity and voltage level, powerusers put forward higher requirements on the reliability of power supply. Therefore, fast andaccurate fault diagnosis method is very important to ensure the security of power supply. Thetransient process of high voltage transmission lines contains abundant fault information, basedon that, this paper constructs the high voltage transmission line fault diagnosis as the target,and to do research for the method of fault classification and fault location on transient signals.Firstly, analysising the fault feature of high voltage transmission line as the foundation,from the perspective of energy, with the EMD decomposition combined with traveling waveenergy of transient current, defined IMF energy, energy weight coefficient and relative energycoefficient as parameters to characterize the features of short circuiting to dig deeper of faulttransient information. Secondly studies single-phase and two-phase grounding fault, phase tophase short circuit and three-phase fault, the energy weight coefficient and relative coefficientbetween fault phase and sound phase, also among fault phases have distribution laws.Andenergy distribution laws concluded fault transient current is larger than that of the sound phase,that with the fault feature threshold is used to realize fault type identification, and proposes afault-phase selection algorithm based on transient current of IMF energy. In fault location, thispaper analyzes traveling wave distance measuring principle and some key factors on faultlocation realized by HHT. Selecting high frequency component IMF1as a research object oftraveling wave recognition, then using Hilbert transform get its instantaneous frequency, andtakes the maximum value of the instantaneous frequency, which effectively avoids the overlysensitive to the instantaneous frequency of the mutant defects and improve the recognitionaccuracy of wave head, finally summarizes two terminal fault location algorithm based onHHT.Simulation results show that under different fault conditions and the effects of noise andharmonic interference, the phase selection method can accurately identify the various types of faults with good reliability. Fault location algorithm can calibrate the traveling wave arrivaltime accurately, the results are not affected from the transition resistance and fault initial angle,with high accuracy and reliability, which has positive significance to improve the safeoperation of power grid.