Lightning triggering possibility by transmission tethers of high altitude wind energy exploitation system

To exploit the high altitude wind energy, a concept of umbrella-ladder combination system, in which the polyethylene polymer transmission tethers play an important role, was proposed by a company. This paper studies the lightning impulse characteristics of polyethylene polymer transmission tethers. First the lightning environment characteristics are summarized, especially the potential of thundercloud can be 100MV and the maximum electric field strength of thundercloud reaches about 1000V/cm. The high altitude wind energy absorber will reach into the small lower positive charge region at the base of the thundercloud. Secondly, experiments are performed to get data of the lightning impulse breakdown voltages of the polyethylene polymer tethers with different pollution degree and different humidity degree, the lightning-withstand strength per unit length tether is tested as 250kV/m. Finally, the possibility the tether to triggers the lightning and causes a flashover along itself is discussed while the system is working.