Comparison of Software Packages for Unbalanced Load Flow Analysis: ETAP Versus PSCAD

Abstract

Power systems analysis also called load flow analysis is a very crucial aspect of power systems as it helps in enabling the effective planning and operation of the power system. The prime objective of load flow analysis is to ensure that the power generated at generating units is supplied to consumer load centers in a stable, economical, and reliable manner. Several methods have been developed for load flow calculations, the most common of these being the Newton-Raphson method, the Gauss-Seidel method, and the Fast-Decoupled method. To make power systems analysis easier and more convenient, several software packages have been developed making use of one or more of the mentioned methods. Each of these software packages has its error margin in load flow calculation. The objective of this paper is to compare the efficacy of two software; Electrical Transient and Analysis Program (ETAP), and Power System Computer-Aided Design (PSCAD) in unbalanced load flow analysis. Three IEEE test feeders are used; the IEEE 4 node, 13 node, and 34 node test feeders. Unbalanced load flow analysis of the test networks is done using ETAP and PSCAD, and the results obtained are compared with benchmarked results. For The 4 node and 13 node test networks, it is observed that the resulting node voltages with ETAP agree closer with published results compared to those obtained with PSCAD. In the case of the 34 node test feeder, the results obtained using PSCAD are better than those obtained with ETAP. To validate the overall efficacy of one software for unbalanced load flow analysis over the other, a larger number of unbalanced networks need to be analyzed with both tools and the results compared against benchmarked results. Keywords— ETAP, PSCAD, Unbalanced load flow, Distribution network, Power systems analysis