Corrosion Conditions Analysis of In-Service ACSR Overhead Lines

Abstract

The corrosion conditions of in-service aluminum conductor steel reinforced (ACSR) overhead lines in typical climate were studied by using macroscopic and microscopic methods. According to its operating environment, the corrosion causes were also analyzed. It is found that the corrosion of the outer aluminum stranded conductors is more serious than other parts. And partial corrosion pits have been found on the outer layers of aluminum stranded conductors. While there is no obvious corrosion appeared on the steel core matrix. Additionally, corrosion products can reduce the corrosion rate of aluminum stranded conductors but accelerate corrosion of the steel core. Through this research, more attention should be paid to monitor the aluminum stranded conductors.

Characteristics of Wires of the Long-Operated Aluminum-Steel Cable at Different Places on an Overhead Power Line Span

“…In the case of only one layer of outer wires, only the central Al wire or steel core is lubricated. Cables in overhead OPLs are often used without additional insulation (bare), see e.g., [5,11,[13][14][15][16]. Sometimes, for better protection against atmospheric corrosion, OPLs use jacketed cables made of plastic material [17,18] or Al-1.6%Mn alloy [19].…”

“…In the literature, stranded all-aluminum cables are referred to as all-aluminum alloy conductors (AAACs) [4,7,8,[20][21][22][23][24][25][26][27] or, separately, all-aluminum conductors (AACs) if all of the wires in the cable are made of high-purity aluminum or aluminum conductor alloy-reinforced (ACAR) if the wires are made of technical-grade aluminum [28]. Stranded steel-aluminum cables are called aluminum conductors (or cable or clad) steel-reinforced (ACSR) [4][5][6][7]11,12,14,15,26,[29][30][31][32][33][34].…”

“…Earlier, to investigate the processes occurring during the operation of cables, cables were studied not only immediately after operation in OPLs [5,11,12,14,15,[24][25][26]30,34] but also after fatigue tests [6,16,[20][21][22][23][27][28][29][31][32][33]35,36], which simulated "aging" of wires (changes in microstructural, structural, and other properties) under real operating conditions or after heat treatment [8][9][10]. Both AAAC [6,8,16,[20][21][22][23][24][25][26][27][28]36] and ACSR [5,6,11,12,14,15,26,[29][30]…”

“…A wide range of experimental methods were used for research, such as optical microscopy (OM) [5,11,12,14,15,[20][21][22][23]25,27,29,30], scanning electron microscopy (SEM) [5,11,12,14,15,[20][21][22][23]27,30,32], energy-dispersive X-ray microanalysis (EDX, also energydispersive X-ray spectroscopy in some articles, abbreviated as EDS) [5,11,14,20,24,25,27,30], X-ray diffraction (XRD) [14,15,[24][25][26][27], electron backscatter diffraction (EBSD) [24][25][26][27]34], densitometry [24][25][26][27]34], the acoustic-resonance ...…”

“…For instance, the effect of both tensile mechanical stress [20,21,28,29] and the amplitude of displacements at bending [6,[21][22][23]28,29,31,35] were investigated, as well as that of annealing temperature [8,9] and mechanical defects of Al wires during their production [7], effect of clamp material [23,31], elemental composition of Al wires [6,22], presence of a steel core [6,26], corrosion due to exposure to ambient air during operation in power lines [5,14,15,30], forest fires [10], and the environment during fatigue tests (either room atmosphere or NaCl solution) [32]. Changes in the microstructure, structure, chemical composition, and physical properties of wires from cables were also studied after their operation in OPLs for various service lives ranging from 8 to 62 years [5,11,12,14,15,[24][25][26]30,34] and after fatigue testing [27,36].…”