Evaluation of Harmonic Current Limit for DG Connected to Grid

The installation of inverter-based distributed generation (DG) has been increasing significantly in recent years. The increased penetration will inevitably inject harmonic components into the power grid, affecting the safety and stability of the power system. The detailed regulations on the harmonic limits of power systems have been provided in manly standards. However, there are few standards that limit harmonics for grid-connected DG separately. This study analyzes GB/T 14549–1993 and GB/T 17625.8 of Chinese standards, and compares harmonic limits of them under different DG installation scenarios. It provides a theoretical basis for judging whether DG harmonics exceed the limit in practical applications, and contribute to the formulation of relevant standards for DG grid-connected harmonic levels.