Electric power quality is an aspect of power engineering that has been with us since the inception of power systems. The measurement of the quality of the electric power in a network is therefore becoming an urging need especially in a deregulated electricity market. In the paper, the types of power quality variation are described and the method of characterizing each type with measurements are presented. By using the advances of power quality monitoring equipment and tools, analysis on power quality measurement result are described. The increased amount af data being collected requires more advanced analysis tools. power quality monitoring has advanced from strictly problem solving to ongoing monitoring of system performance.
