Locating Transient Disturbance Source Using Complex Wavelets

This paper presents the application of complex wavelet energy for locating the source of a transient disturbance. By using the complex wavelet transform, the current and voltage at the monitoring point are decomposed into its real and imaginary parts. The transient power based on complex wavelets at the monitoring point is then calculated and the complex wavelet energy is obtained by integrating the transient power. The wavelet energy of a transient disturbance is plotted against time in which, the transient source location is determined by examining the gradient of the wavelet energy. From the wavelet energy plots, it can be concluded that a negative gradient of wavelet energy indicates that the transient source is downstream or in front of the monitoring point. On the other hand, a positive gradient of wavelet energy of the transient source indicates that the transient source is upstream or behind the monitoring point. To verify the wavelet energy method, simulations using the PSCAD/EMTDC software have been performed. Switching of capacitors has been simulated for generating the oscillatory transient of a power distribution system. Simulation results prove that the complex wavelet energy is capable of correctly locating the transient source in a power distribution system.