Research On Transmission Line Fault Location Based On Wavelet Transform

Power cable fault occurs regularly in power system. Fault location is necessity to eliminate the fault. Accurate fault location can reduce the time to find out the fault point and the cost of power cable cut.The principle of the low voltage pulse method is deeply investigated .The necessity disciples and characteristic of the incidence wave and the reflect wave are also deeply investigated. Using multi-resolution and maximum value of the wavelet transform, a method of transmission line fault location is devised. Using MATLAB to simulation this method, we get a good result. The improved wavelet soft-threshold method is presented based on the different propagation property of real signals and white noises under the wavelet transform. It can accelerate the separation of the signal from the noise and get higher SNR for the reconstructed signal. Analyze the inextricable problem of the method based on traveling wave, we using the method based on the subtraction of two electrical currents to resolve the problems and this method obtains a good result through the simulation.The principle, excellence and disadvantage of the method based on traveling wave and the method based on the subtraction of two electrical currents are compared in details. The principle, excellence and disadvantage of the method of transmission line fault point location and another method of transmission line fault point location witch expound in this thesis are compared.