Stability Impact of PV Inverter Generation on Medium Voltage Distribution Systems

With an increasing number of photovoltaic (PV) inverters in the distribution system, their impact is no longer negligible, especially in the aspect of dynamic interaction. Accordingly, a comparison is done among PV inverters of different capacities, at different physical locations, at different reactive power control modes and at different operation states, to determine their impact on the system operation and stability. Generalized Nyquist Criteria (GNC) based on impedances in DQ frames is used for stability assessment, which is validated by time domain simulation results from MATLAB. And selected experiments are conducted to validate the findings of the study. From these, guidelines are formulated to manage PV inverter connection locations and reactive power control strategy and parameters.