Citation

Zhang J, Huang L, Chen T, Su G. Fire Safety J. 2021; 126: e103434.

Copyright

(Copyright © 2021, Elsevier Publishing)

DOI

10.1016/j.firesaf.2021.103434

PMID

unavailable

Abstract

Poor electric contact is one of the main reasons that trigger electrical fires. It can cause local overeating and transfer heat to the surrounding insulation and other flammable materials. In this paper, we propose a novel approach to analyze the thermal hazards of poor contact based on finite element method simulation. We build a heat transfer model, coupling fluid flow and thermo-electric effect for loose electric contact between the blades and reeds based on COMSOL Multiphysics. The model is validated by some experimental results from literatures. Then, with this model, we analyze the electrical fire risks based on temperature rise and radiation heat flux, considering the influence of four factors, contact pressure, contact surface roughness, load current and air velocity. We divide the electrical fire risks into 5 levels based on near air temperature rise or radiation heat flux, which are no risk (<20 °C or <1.4 kW/m2), low risk (20-60 °C or 1.4-5 kW/m2), relative high risk (60-150 °C or 5-10 kW/m2), high risk (150-250 °C or 10-20 kW/m2), and super high risk (>200 °C or >20 kW/m2). The critical conditions are found for different risk levels. It indicates that the risk levels classified by air temperature rise are more reliable than that by radiation heat flux. We also analyze the influence of these factors and calculate their importance with the random forest and the decision tree. It is found that contact pressure contributes most to the electrical fire risks. That implies avoiding the loose electric contact between receptacle and plug is an effective measure to prevent electrical fires.

Language: en

Keywords

COMSOL Multiphysics; Electrical fire risks; Poor electric contact; Simulation analysis; Thermal hazards