Total harmonic distortion decomposition depending on distortion origin

The total harmonic distortion (THD) ratio is a well-known parameter that characterizes the distortion degree at a specific point of the grid. In this paper, a decomposition of the THD will be presented in order to determine the responsibility of the distribution company and the electrical energy consumer for the harmonic distortion measured at the point of common coupling (PCC). For this study, the power quantities proposed in the new Standard IEEE 1459-2000 and developed by L. Czarnecki were considered. The algorithm of the decomposition will be implemented on a measurement platform based on a digital signal processor (DSP). The general structure of the system-hardware and software-are also discussed. Finally, the apparent powers, defined by both L. Czarnecki and the IEEE Standard, are also compared for single-phase and three-phase systems.

I. Introduction

The use of devices sensitive to power system disturbances, especially information and communication technology equipment, and the widespread use of nonlinearly behaving power electronic converters in current electrical distribution systems would seem to be an unstoppable process. This means that power theories are becoming more and more important in applications such as compensation, identification of the harmonic load, distortion voltage reduction, and instrumentation.