Simulation and power quality analysis of grid-tied inverters for distributed generation

Changes in the United States electric power system led to an open transmission and distribution system where new power producers were able to compete with established utility companies. The original composition of the electric system is changing dramatically with distributed generation, i.e., the penetration of different power technologies capable of supplying power at the distribution level. Having generation at the distribution level presented great advantages, but there was a need to study the issues regarding the reliability and quality of the supplied power. The objective of this thesis was the simulation and analysis of power electronics inverters, and their effects when interconnected to the electric power system as interface of distributed generation. The main focus is on the behavior of inverters used in grid-tied applications such as interconnecting photovoltaic systems to the grid. An integrated software environment was created in which power electronics and power quality considerations are taken into account to assess the interconnection of distributed generation to a power grid. A complete analysis was made of applicable standards and the use of the software environment in addressing some of the pending issues in those standards. The contribution of this work is a software tool for inverter simulation and DG interconnection issues, and a power quality assessment procedure for grid-tied inverters.