Critical evaluation of the performance of the method of harmonic power flow to determine the dominant source of distortion

Abstract

In many guidelines contained in documents approved by electrical regulation agencies, harmonic distortions appear as an important issue among other indicators of electric power supply quality. In general, these standards consider specific aspects, such as definitions, measurement procedures, and benchmarks. Overcoming challenges related to voltage distortions and establishing ways to determine the responsibility for possible violations of given limits are also important matters. The literature describes procedures to characterize the major responsibility among the agents involved (supplier and consumer) or, in a more advanced way, the individual contributions. One of the simplest and most widely used methodologies for identification of the major source of harmonics consists of determining the direction of harmonic power flow by comparing the fundamental and harmonic power signals. Most commercial power quality measuring equipment has the ability to quantify fundamental and individual harmonic powers. However, this study shows the weaknesses of this method. Theoretical analyses, as well as computational and experimental studies, were performed for a hypothetical electrical arrangement. The electrical network was investigated under different operating conditions, and the power harmonic approach was used to determine the dominant harmonic source. The results were then used to evaluate the effectiveness of the methodology to find the correct response.