Comparative analysis of fretting fatigue resistance between overhead conductors made of aluminum alloys 900 MCM and 823 MCM

ABSTRACT

The electric transmission and distribution industries and utilities are looking for the most optimized components for their transmission lines. Thus, there is a need to improve the formation of the overhead conductor, which is the costliest element of electric transmission lines. Under these circumstances, conductors formed solely of aluminum wires appear to be more advantageous over aluminum conductor steel reinforced, obtaining better ampacity/weight ratios, thus lowering the transmission cost. The objective of this article was to verify the influence of the fretting fatigue phenomenon under controlled conditions, on the AA 6201 T81 and AA 1120 H19 aluminum alloy wires, which form the overhead conductors CAL 900 MCM and CAL 823 MCM, respectively. To achieve these goals, an experimental program was created capable of acquiring the data on the fatigue life of the overhead conductors and the wires separately, in order to verify the influence of fretting under a 750 N normal contact load parameter. In the results, the CAL 900 MCM achieved the lowest fatigue life, despite it made of an alloy with better mechanical properties. The same result was obtained in the fretting fatigue tests on wires, so it can be inferred that the AA 6201 T81 alloy, although it has better fatigue resistance, is more susceptible to failure in the presence of fretting when compared to AA 1120 H19 alloy.

Keywords
fretting fatigue on wires; contact between aluminum wires; AA 1120 H19 alloy; AA 6201 T81 alloy