A Finnish research group has created a new workflow to prevent voltage rise in bifacial vertical solar power systems located at high latitudes. According to their findings, vertical bifacial PV can have a 46% higher power output compared to conventional monofacial PVs in the Nordics, and at the same time it also has a better temporal compatibility between PV production and consumption.
They explained that their new approach is intended to avoid grid voltage spikes that occur when solar power production exceeds demand, where high voltages can potentially damage the grid and connected electrical equipment. “Therefore, the voltage must be limited below the threshold either by identifying the maximum allowed solar power capacity of the distribution network or by setting a limit for the maximum permitted solar power production and limiting overproduction,” they explained.
The new methodology works through five main steps: data collection, degradation modeling, transposition modeling, electrical and thermal modeling, and low-voltage network analysis. The second and third steps provide a calculated global tilted irradiance (GTI) profile for the selected location, time and PV direction, which is then converted to solar power, taking into account weather data and PV system characteristics. LV network analysis prevents oversizing of the PV system to avoid overvoltage.
The scientists applied the workflow to different cases of monofacial projects and bifacial vertical PV systems. They analyzed the PV production profile, the electrical load profile and the combination of variables for the PV hosting capacity, which they say is a key factor in avoiding surge events.
In their analysis, the researchers found that the maximum allowed PV capacity is usually limited by short periods of time between 1 and 30 minutes. These phases are characterized by high solar electricity production and sudden fluctuations in electrical load and solar electricity production. “This highlights that controlling such periods with different voltage regulators, or allowing over- and under-voltage events in the short term, can significantly increase PV capacity,” they noted.
According to their findings, vertical bifacial PV can have a 46% higher power output compared to conventional monofacial PVs in the Nordics, and at the same time it also has a better temporal compatibility between PV production and consumption.
The new method is presented in the article “A Comprehensive Methodological Workflow for Maximizing Solar Energy in Low Voltage Grids: A Case Study of Vertical Bifacial Panels in Nordic Conditions”, published Solar energy.
“Additional work is needed to include more realistic electricity load models and economic analyzes in the methodology,” the Finnish team stated. “Furthermore, because the test network used only covered a very small geographical area, resulting in small losses in the power lines, it probably overestimates the absolute values of the maximum solar production compared to most real distribution networks, although this allowed for a comparison. relative values between different cases.”