Evaluation of harmonic trends using statistical process control methods

Power quality data collected from power quality monitoring instruments are generally voluminous. They are typically stored without analysis unless there is a concern about a particular problem. Data analysis on a regular basis is time consuming and costly. Ideally, analysis modules should be made available to analyze data and construct important information about the health condition of the overall power system and its individual components. This paper presents the application of the well-known statistical process control to analyzing harmonic trend variations. Specifically, it describes how the method can be used to determine if the statistical variation in the harmonic trend represents normal variations or due to problems in the system.