Study on grounding design for lightning of tubular composite material towers in 110kV overhead transmission line

The composite tower body insulation may be used to enhance the phase-to-ground and phase-to-phase insulation strength for transmission line towers so as to increase the transmission line lightning protection capacities. This study project is carried out to achieve this purpose, by putting forward one new type of lightning ground down lead modes, that is, the ground down lead suspended in the internal side. As shown in the test and calculation evaluation results of the lightning performances, the lightning impulse insulation strength and the lightning trip rate of the composite towers by utilizing the design the ground down lead suspended in the internal side may be respectively increased by 28% and decreased by 54% than those by utilizing the ground down lead mode along the tower, respectively.