Detection of transient events using the Hartley Phase Cepstrum for improved power quality

Abstract

In Electric Power Quality (PQ), transient disturbances of short duration in the voltage or current waveforms supplied by the Utility have a severe impact on the operation and safety of both the user equipment and the total energy network. Advanced signal processing methods are currently being developed and employed for the detection of transient PQ events. The Phase Cepstrum of the waveform data is proposed here as a tool for the detection and localization of such PQ transients. Specifically, the Hartley Phase Cepstrum is employed thanks to certain advantages it bears as to its conventional Fourier counterpart. These stem from the properties of the corresponding Hartley Phase Spectrum, which carry over to the cepstral domain because of the analytic relation that holds between the two domains. Unlike the Fourier Phase Cepstrum, the Hartley Phase Cepstrum does not suffer from ambiguities introduced by the phase 'unwrapping' processing step; therefore, the evaluation of the Hartley Phase Cepstrum is an invertible process. For the same reason, the Hartley Phase Cepstrum offers improved detection and localization of a sequence of transient events. (5 pages)