Christian Vogt - Fire Protection Engineering Department MS Thesis Defense

Fire Protection Engineering Department

MS Thesis Defense

Christian Vogt

Tuesday, April 29, 2025, 1:00 pm – 2:00 pm, 50P1226

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Quantifying the Wildfire Risk to Electrical Systems in Solar Farms

Committee

Albert Simeoni, Ph.D. (Department Head; FPE WPI)

James Urban, Ph.D. (Advisor and Assistant Professor; FPE WPI)

Dong Zeng, Ph.D. (Principal Research Scientist, FM Global)

Abstract

Ground-mounted solar farms are becoming increasingly prevalent, with those adjacent to wildland areas facing exposure to wildland fire, in particular grass/surface fires. While the fire behavior of roof-mounted solar systems has received widespread attention and has been the subject of intensive study, efforts to understand the impact of wildfires on the relevant components of solar farms have been limited. 

As human development continues to encroach into wildland areas, wildfires in solar farms are expected to become more frequent, and their impact could be exacerbated by the effects of climate change. In addition, green mandates such as no-mow zones are becoming more common, limiting one of the most effective ways to reduce the fire hazard. Furthermore, these fires can have a tremendous potential for cascading effects, such as disrupting evacuation and emergency communication efforts due to power outages, while also posing direct hazards and challenges to firefighters and causing significant losses to operators. Given the severe consequences of these fires, a better understanding of the interactions between wildfires and solar farm infrastructure is critical.

One vulnerable component of ground-mounted solar farms is the power cable that transfers energy from modules to the electrical grid. These cables are susceptible to damage by fire through radiative and convective heating from the fire below. This work seeks to better understand this risk through a series of experiments and the development of an associated predictive model for the heating and thermal damage of the cable while exposed to fire. In these experiments, dry hay was used as fuel to simulate a grass fire while an instrumented cable surrogate was suspended above the fuel bed to measure temperature rise as the fire passed underneath. The effects of fuel loading, fuel bed inclination, the presence of an overlying panel, and the resulting fire behavior on the cable temperature profile were systematically analyzed. The computational model combines the Rothermel fire spread model and Quintiere’s plume correlations to characterize convective heat transfer; and a custom radiation heat transfer implementation to predict the temperature rise of cables suspended above surface fires. The model is able to account for variations in environmental conditions and solar farm configurations, such as cable height and diameter, providing valuable insights for engineering analysis and risk mitigation strategies.

This research aims to identify the degree to which grass and surface fires endanger the overlying electrical components and to provide engineers and operators of solar farms with a better understanding of this fire exposure pathway. To that end, the model provides a tool for engineers to perform improved fire risk analysis.