A Novel method to Detect and Evaluate Power Quality disturbances using Hilbert Phase Shifting and CORDIC Algorithm

Abstract

Power Quality (PQ) is an umbrella term that encompasses all the aspects connected with amplitude, phase and frequency of the voltage and current waveforms existing in a power circuit. Adverse Power quality environments refer to the transient conditions developing in the power circuit and eventually affecting the load and the source. Power Quality Monitoring refers to the task of detecting the disturbances in the system which leads to the deterioration of the Power Quality and the immediate execution of measures to compensate the same. The various disturbances that adversely affect the quality of power include voltage sags, voltage swells, voltage fluctuation, transient oscillations, harmonics and inter- harmonics. The work aims at finding a unified and comprehensive method to detect and evaluate each of the Power Quality disturbances. The detection is facilitated through the Hilbert Phase shifting mechanism and the same detection output is used for the accurate evaluation of the disturbances based on CORDIC Algorithm. The methods developed are hindered by the presence of Noise in the system; hence emphasis has been laid to suppress noise for the efficient working of the algorithm which bases its working on Hilbert’s Phase shifting property. The noise suppression is basically achieved by employing Mathematical Morphological filters and applying them before the signal is subjected to the detection and evaluation algorithm. The evaluation is based purely on the phase determining property of CORDIC (Coordinate rotation digital computer) Algorithm. A suitable model has been determined to efficiently account all the disturbances.