Characterizing solar PV grid overvoltages by data blending advanced metering infrastructure with meteorology

If rooftop-installed solar energy systems generate more energy than locally consumed, the excess is fed into the electricity grid, increasing the voltage. Rising penetration levels of solar photovoltaic (PV) systems increase voltage levels, thereby threatening power quality. The extent to which solar PV cause grid issues in actual, nation-wide distribution grids, and how these issues correlate with cloud conditions and irradiance variability has yet to be quantified. This work provides a spatial and temporal characterization of overvoltage events linked to solar PV, using novel data sources. The analysis is based on over 200,000 events from advanced metering infrastructure (AMI) spanning 1/3rd of the Netherlands, combined with satellite observations and 1-minute irradiance measurements. As a result, we find that the typical duration of overvoltage events is in the order of 5 min, and frequently-reporting meters are geographically dispersed. While overvoltages are driven by high PV generation, we do not find evidence that local, short-term irradiance peaks result in additional events as compared to clear sky conditions. However, we do find that median overvoltage event occurrence on Sundays is more than 2.1 times that of weekdays, which can be related to low energy consumption. Our findings indicate PV hosting capacity to be reached throughout the service area simultaneously, and surprisingly show no reduction in event duration by inverter-or grid control. Notably, while a sharp increase in occurrence is observed, over voltage events are still scarce in absolute terms, with only 0.1% of the AMI reporting more than 10 events in spring-summer 2020.

Automated summary

The study investigates overvoltage events caused by solar photovoltaic systems and finds that the typical duration is around 5 minutes, with Sundays having a 2.1 times higher occurrence rate compared to weekdays. However, there is no evidence that local, short-term irradiance peaks result in additional events. The research also shows that while the number of overvoltage events is increasing, they are still rare in absolute terms.