A software based methodology for calculating powers in three phase networks

Abstract

In this paper DIgSILENT PowerFactory software results are evaluated against the IEEE and Czarnecki definitions and there from a software based methodology is introduced for calculation of powers in nonsinusoidal three phase networks. The power definitions proposed by the IEEE are reviewed and their similarities and differences to the conventional approach are introduced. The concept of orthogonal current decomposition for three phase networks proposed by Czarnecki and used as the basis upon which his power theory is developed is reviewed and compared to the conventional and IEEE approaches. The power indices used by DIgSILENT to generate results are listed and the need for a MATHCAD program to supplement it is identified, so that the IEEE and Czarnecki powers can be obtained. Three case studies were conducted with different network topologies. Taking into account symmetrical and asymmetrical sources and balanced and unbalanced loads. The results are compared and analyzed and the effectiveness of the software methodology is demonstrated.