Analysis of power quality variations

Power quality is an important issue that has caused increasing attention from both the suppliers and the users of electricity. And it seems to be a tough mission to analyze power quality problems since power system is always subject to unexpected problems. However, thanks to the hard work of numerous power engineers, obvious advances have been achieved in the measurement and analysis of power system variations in recent years. This paper discusses the categories of power quality variations, summarizes the methods used to analyze and measure these variations and provides some relevant examples.