Interharmonic and Harmonic Steady-State Computation of a Grid-Tied Photovoltaic System

Modern electric power systems, that involve distributed generation resources, should exhibit pure sinusoidal voltages/currents. However, due to the inclusion of alternative energy systems, e.g., wind turbine generators and photovoltaic systems, electrical waveforms contain a wide frequency spectrum. This waveform distortion is mainly due to the involved power electronic converters and nonlinear loads, among others, and propagates into the neighboring network. Steady-state computation of these distributed generation systems requires mathematical models that permit to represent accurately both low- and high- frequency dynamics. Besides, such computation is challenging for commonly used software tools as they usually require very small time-steps and long simulation time-windows.This paper describes a flexible harmonic domain methodology for steady-state computation of a grid-tied photovoltaic system. It is shown in this paper that the proposed methodology provides accurate harmonics and interharmonics representation.