Comparison among Two-Phase Three-Wire AC Off-Grid Power Systems

The update of the power system moves over to connection of small distributed energy resource through grid-interactive converters. The electrifying process of the distribution power system allows the implementation of different grid configurations, such as those based on two-phase three-wire systems that are appealing for residential zones, commercial areas and off-grid systems. The off-grid two-phase three-wire topology can be implemented considering voltages as an extension of the conventional three-phase system (abn), voltages in quadrature (αβn), or voltages with opposite phases (xyn). Then, this paper aims at comparing the three off-grid power system topologies in terms of power quality characteristics, sizing of DC capacitor of grid-connected inverters, sizing of neutral conductor, and integration with the conventional mains. To accomplish those goals, a mathematical approach considering the Conservative Power Theory and computational simulations are shown and discussed.

I. Introduction

The development of new power electronics technologies has been providing the use of small distributed resources for the electrical energy generation. This scenario allows the interconnection and interoperability of several kind of distributed generators (DGs), loads and storage systems into one single entity capable of isolated operation.