Advanced techniques for power quality analysis: a real case study

This paper presents a real case study relating to power quality. An industrial customer power system is investigated in order to analyze misoperation linked with the switching of harmonic compensation filters. First, overvoltage transients are recorded on the main set of busbar. Then, the whole power system and the switching of the harmonic filters are simulated with EMTP. Results are compared with real records. Furthermore, the wavelet theory is used for the analysis of currents and voltages during switching. A comparison between simulations and measurements shows the accuracy of the method presented in the analysis of transient events. Finally, an analytical study of the switching transient has confirmed results about the main frequencies measured. The whole method (EMTP simulation and wavelet analysis) is a useful way to investigate industrial customers´ power systems from a power quality point of view