Corrosion Failure Analysis of Inner Al Layers of 35 kV Aluminium Cable Steel Reinforced (ACSR) Conductors

The fracture surface of corroded inner Al layers of 35 KV aluminium cable steel reinforced (ACSR) conductors acrossing the 81# and 82# towers used on an island in Fujian Province was studied by SEM and EDS.The results indicated that the fatigue fracture surface was mainly composed of phases of Al,Al(OH)3 and Al5(CO3)3(OH)13·xH2O.In addition to the Al and O,C,Si,S,Cl,Na,Mg,Ca,etc existed in the surface.C,Si and other elements appeared primarily on the surface and areas about 250 μm to 500 μm away from the surface.The corrosive media such as marine atmosphere,CO2 and dust caused severe corrosion of the inner aluminum stranded wires.A large number of corrosion products adhered on the substrate and there were some divergent cracks centred on the corrosion areas.Under the effect of corrosion,aeolian vibration and line tension,corrosion areas were naturally turned into multiple corrosion fatigue sources and fatigue cracks propagated with half elliptical contour line,and eventually led the materials to fracture.