Expert system for the analysis of power quality

The use of capacitors for correcting the power factor is a very well known approach in industry. However, the increase of harmonic sources in power systems is heightening the risk of resonance and, consequently, a drastic decrease in electric power quality. In order to keep the rating voltage, the power factor, and the voltage and current harmonic distortions within acceptable limits, an expert system approach was implemented. Based on this approach, a software program that is able to decide about the optimal distribution of the capacitor banks has also been developed. The program decision is based on the rating voltage, the power factor, and the whole voltage and current harmonic distortions. When necessary, the computer program decides on the use of filters for harmonic compensation, indicating the best filter and the corresponding tuning frequency. Furthermore, the approach is able to deal with some aspects concerning the electric losses, both on the rating frequency and on the harmonic components.