Application of a differential technique for characterization of waveform distortions

This paper introduces a differential technique that can be applied to extract information from distorted power voltage or current waveforms for power quality studies. This technique has been successfully applied for real time signal extraction by a unique power frequency communication technology, which uses the medium voltage distribution circuits for communication. This method is especially useful to identify sources of burst type distortions, such as arc welders or arc furnaces, high impedance faults, flicker causing devices, etc. The Fourier series or Fourier transform techniques, while providing very useful information, in some cases tend to mask the characteristic features of the contaminating sources due to averaging. Quite often it is not intuitively clear from the results what the causes are of the distortion. To analyze the results requires a high degree of expertise and experience in order to be able to identify the cause of a distortion. The differential technique can serve as a powerful complementary tool to existing algorithms used in power quality studies