Critical diameter of particles produced in overhead line conductor clashing

Abstract

Wildfires are occurring over the world and some of them were close to electrical power lines. Conductor clashing has been blamed in many cases. During the conductor clashing some of the droplets are very hot which can ignite the biomass on the ground. This paper deals with the original mathematical model for the calculation of the particle size that has sufficient heat and temperature to cause ignition of flammable material on the ground. The critical diameter is the least diameter of the particle caused by conductor clashing that will, in spite of the particle cooling on the way, be sufficient to ignite the biomass on the ground. The proposed algorithm, based on this model, is robust and can be applied to any type of biomass on the ground, any type of conductor, as well as to any height of energized conductor clashing. The presented examples show the impact of the conductor clashing height over the ground, the relative humidity and the wind speed on the critical diameter in usual conditions in Mediterranean countries (the needles of the Aleppo pine on the ground under energized overhead power line with aluminum conductors). This work can help in determining the likelihood of the fire beginning due to the conductor clashing and may also help in defining the fire protection measures. Furthermore, it might be used by the court experts for doing their expertise. The calculation results show that the critical diameter can be less than the diameter of the largest particles measured in several experiments of different authors.