Electric power quality: types and measurements

Electric power quality is an aspect of power engineering that has been with us since the inception of power systems; however, topics in power quality have risen to the forefront since the advent of high power semiconductor switches and networking of transmission and subtransmission systems. Also, the trends in modern power engineering have been to extract the most from the existing installed system, and this too has placed stress on issues of sinusoidal waveform fidelity, absence of high and low voltage conditions, and other ac waveform distortion. In this paper first, types of power quality variations are described and the methods of characterizing each type with measurements are presented. Then, advances in power quality monitoring equipment and tools for analyzing power quality measurement results are described. The increased amount of data being collected requires more advanced analysis tools.