Strain Clamp It is used to fix the wire to withstand the tension of the wire and hang the wire to the metal fittings on the tensile

string or the tower.

Poor compression in the strain clamp often makes the strands overheat and fracture.There exists a certain gap between

conductors and the strain clamp if the strain clamp is compressed poorly.The ashes, oxide, corrosion and abrasion tend to

gather and scale in the gap, forming scale layers of high resistivity. As the exposure time increases, the layers expand and

thicken, which causes the worsening of conductive properties of current and heat, and leads to abnormal temperature

 elevation, the degradation of microstructure and properties and strands fracture at last. In consideration of this kind of

strands fracture phenomenon and through FEM, non-uniform temperature field influenced by scale layer in the clamp has

been analyzed and the quantitative relationship between the scale layer, peak temperature and current has been obtained.

The results of material experiments show that the strands vary from each other in the roundness of shear lips. Serious erosion

is found on the surface of outer Al (aluminum) strands attaching to the clamp, while there is almost no erosion mark on the

surface attaching to inner Al strands.Erosion spots in Al strands surface attaching to the scale layer are the deepest, and

each erosion pit is large and some of which have even developed into plaques. The interacting deterioration of scale and

temperature causes the Al strands attaching to the scale layer to fail and then led to fracture-temperature domino effect

of other strands. The longitudinal fibrous microstructure of steel strands disappeared as the temperature rose. The

plasticity of strands increased after recovery and recrystallization.The rapid degradation of mechanics properties resulted

in the drop accident of conductors.