Development of an Expert System to Identify and Estimate Harmonics Produced by Power Electronic Converters

The existence of harmonics is one of the significant means of deteriorating the quality of an electric power supply. In order to fully understand the problems caused by harmonics, sources of electric power harmonics needs to be identified and this normally requires power quality monitoring and analysis. However, monitoring usually generates vast amount of data which makes manual inspection of the disturbance waveforms a tedious and time-consuming task. Therefore, it is desirable that the data collection process is automated such that monitoring equipment not only captures harmonic waveforms but also performs the task of recognizing the various types of nonlinear loads present in a system. With such an automated system, faster and more efficient analysis of the databases can be achieved. The issue of automatic analysis of various power quality disturbances has been addressed in the form of the development of expert systems for power quality event identification or the classification of disturbances such as transients and voltage sags (Kazibwel and Sendaula 1992). The expert system for analyzing power system harmonics focuses on symptoms associated with harmonics related problems and providing possible solutions (Schlabbach 1994, Shipp et al 1995).