An approach for assessing high-penetration PV impact on distribution feeders

The variability of solar power due to cloud shadows with high penetration levels can cause technical issues such as power fluctuation and voltage flicker in power distribution feeders. To help distribution planners better understand and predict these likely impacts on voltage quality and avoid overly conservative decisions on the amount of PV installed on a feeder, a comprehensive simulation method is needed to model and address these problems. To this end, this paper presents a simulation and analysis approach that uses a cloud shadow model to recreate the variable output power of both distributed and large centralized PVs at various locations on a feeder. Simulations are made on an actual EPRI test feeder. EPRI's OpenDSS distribution simulation program is driven through MATLAB. The feeder is monitored at all buses, and PV induced voltage quality issues are measured, including the dynamic reaction of voltage control devices. The example feeder illustrates the usefulness of the new evaluation method to address and quantify impacts of large amounts of PV systems on feeder steady-state over voltage, voltage fluctuation level and flicker, and voltage regulation device operation. Results for distributed PV show that PV levels as high as 50% can be tolerated.