Software predicts harmonic problems and simulates alternative solutions

Many articles have been written about the growing harmonic problems in present day power systems. The topics range from the fundamentals of harmonics to specific case studies showing harmonic cause and effect relationships. The articles follow a common theme: they describe harmonic problems and recommend possible solutions after the problems occurs. This article describes how computer simulations can be used to predict harmonic problems before they occur, and evaluate corrective alternatives prior to implementation. A case study demonstrates a computer simulation used to eliminate harmonic problems at a cement plant. The study involves: (1) initial data collection and harmonic measurement; (2) computer simulation of the initial plant to compare measured harmonics with predicted harmonics; (3) computer simulation to evaluate the proposed addition of capacitors and design corrective harmonic filters; and (4) installation of the corrective filters and final data collection to verify the design effectiveness.