Wavelet transforms for real-time estimation of transmission line impedance under transient conditions

Abstract Waveforms of voltages and currents in electrical power systems may include higher harmonics, transient components and random noise. For control and protection devices, it is necessary to estimate parameters of the basic waveform. The most well-known methods are based on the Fourier technique. The estimated phasors of the basic component can be applied to the calculation of the impedance of a faulty transmission line. In this paper, the current and voltage phasors were estimated using complex wavelets. The filter properties of the wavelet approach are better than those of the Fourier.