带电条件下光伏火灾灭火最小安全距离的建模与计算方法

Abstract Although photovoltaic power generation is widely recognized as a clean and renewable energy source, it also introduces an increased risk of fire and potential structural damage to buildings. The continuous high voltage direct current (DC) output from photovoltaic panels presents a significant risk of electric shock during firefighting operations. Water, a cost-effective and efficient fire extinguishing agent, is commonly used to suppress photovoltaic fires. However, using water carries the risk of electrical currents traveling through the water flow, increasing the likelihood of electric shock. The current level of the photovoltaic panels, firefighting distance, flow rate, and pressure range of water guns utilized in current models is relatively limited. Moreover, there is a dearth of effective safety distance calculation models for higher current levels and water gun flows. To address the discrepancies between existing models and real-world conditions, this study aims to analyze the risk of electric shock when using water guns for photovoltaic fire suppression under energized conditions and to propose a calculation model that accurately describes the safety extinguishing distance. To achieve this, at first, a photovoltaic fire extinguishing test platform is constructed, and data on electric shock current at the position of a human resistance simulator during the fire suppression process using both fire hydrant guns and multi-function water guns are collected through repeated experiments. The results demonstrate that the experimental platform and test methods employed are practically feasible and can reliably ensure that the relative uncertainty of the test data within a 95% confidence interval does not exceed 19.73%. Then, by integrating theoretical analysis with formula fitting techniques, a calculation model is presented for estimating electric shock current induced by human resistance during photovoltaic fire suppression. The relative errors are 10.5% for the multi-function water gun and 9.6% for the hydrant water gun. Finally, based on these findings, a modeling and calculation method for minimum safety distance for photovoltaic fire extinguishing process, incorporating human resistance under various voltage conditions, is proposed. This method provides a reliable foundation for the rational and effective suppression of photovoltaic fires.