Practical solutions to harmonic assessment of inverter-based resource plants

Inverter-Based Resources (IBRs) are new types of generators entering power systems. There are concerns on the potential harmonic distortions and harmonic resonance impact on the host systems. IBRs use voltage source converter (VSC) to interface with the grid. As a result, IBR units have some unique harmonic generation and response characteristics that are quite differ ent from the traditional line commutated converters (LCC) based loads. This paper presents research findings on several important issues associated with harmonic interconnection studies of IBR plants. Examples include the need for probabilistic summation of the harmonics generated by the IBR units, how to include the impact of a range of grid impedances, and how to quantify the severity of harmonic resonance caused by IBR plants, and so on. The information presented in this paper will help IBR plant designers and power quality engineers to perform harmonic impact assessment properly and with confidence.