*Article*

## **Comparison of Structural, Microstructural, Elastic, and Microplastic Properties of the AAAC (A50) and ACSR (AC50/8) Cables after Various Operation Periods in Power Transmission Lines**

**Aleksandr A. Levin 1,\*, Maria V. Narykova 1, Alexey I. Lihachev 1, Boris K. Kardashev 1, Andrej G. Kadomtsev 1, Nikita D. Prasolov 1, Andrei G. Panfilov 1, Roman V. Sokolov 1, Pavel N. Brunkov 1, Makhsud M. Sultanov 2, Alexander V. Strizhichenko 2 and Ilia A. Boldyrev 2**


**Abstract:** In modern economic infrastructure, Al cables of overhead power transmission lines are used both without and with a steel core (respectively, all aluminum alloy conductor (AAAC) and aluminum conductor steel reinforced (ACSR) cables). In this article, the changes in structural, microstructural, and elastic-microplastic properties have been analyzed for the outer wires of the AAAC (A50) and ACSR cables (AC50/8 cables with a steel core of ~8 mm<sup>2</sup> cross-section, hereinafter referred to as AC50) with the cross-section of the stranded conductor of ~50 mm2, which were in operation for 0–20 years in the Volgograd region of Russia. Using the techniques of X-ray diffraction, electron backscattered diffraction, densitometry, and the acoustic method, the structural and microstructural features of the wires have been compared and found to be correlated with their elastic-microplastic properties. It has been ascertained that the presence of a steel core in AC50 leads to a decrease in the defectiveness of the near-surface layer of their aluminum wires. Compared with A50 cables, the development of void defects in the near-surface layer of Al-wires of AC50 cables slows down (by ~1 year with a service life of ~10 years and by ~3 years with a service life of ~20 years).

**Keywords:** aluminum wires; overhead power transmission lines; XRD; EBSD; densitometry; elastoplastic properties; density; near-surface layer
