PSI - Issue 64

Jayathilake S. et al. / Procedia Structural Integrity 64 (2024) 137–144 Jayathilake S. et al. / Structural Integrity Procedia 00 (2024) 000–000

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was estimated to ensure safe operation under the damage limit for both the 55-year-old and new 6/1/3.75 ACSR and 7/3.75 AAC conductors. In particular, the results of the research led to the following conclusions under the elevated temperature from 25°C to 100°C: • The conductor capacity of 55-year-old aluminum strands decreases by up to 30% while the highest capacity reduction in new aluminum strands is around 10% under the same temperature levels. • The steel strand exhibits a marginal reduction in capacity of around 2% to 4% regardless of the strand condition. • The tension requirement for both ACSR and AAC increases with higher wind velocities but decreases with rising temperatures. • Both new and old ACSR and AAC conductors can operate below the damage limit until they encounter wind velocities at the upper range of the wind hazard curve. • Old AAC conductors can reach the damage limit at lower velocities than those specified in the standard design values. Consequently, ACSR presents a lower risk of failure compared to AAC when considering the same tension force. This study underscores the importance of assessing the risk of failure in old conductors, particularly AAC powerlines in the OPDN, even during the later stages of their service life. Furthermore, it is expected that extending this study to incorporate different sizes and ages of ACSR and AAC powerlines will aid in developing risk rating curves for OPDN conductors. References AER., 2022. State of the Energy Market 2022 . Aggarwal, R., Johns, A., Jayasinghe, J., & Su, W., 2000. An overview of the condition monitoring of overhead lines. Electric Power systems research , 53 (1), 15-22. AS1391., 2020. Metallic materials - Tensile testing - Method of test at room temperature. In. AS2291., 2020. Metallic materials - Tensile testing - Test at elevated temperature. In: Standard Australia, 1 Thecrescent, Homebush, NSW 2140. AS3607., 1989. Conductors - Bare overhead, aluminium and aluminium alloy - Steel reinforced. In: Standard Australia, 1 Thecrescent, Homebush, NSW 2140. AS/NZS1170.2., 2021. Structural design actions, Part 2: Wind actions. In: SAI Global Limited and Standards New Zealand, PO Box 10729, Wellington 6011. AS/NZS7000., 2016. Overhead line design. In: SAI Global Limited and Standards New Zealand, PO Box 10729, Wellington 6011. Bandara, S., Rajeev, P., & Gad, E., 2023. Power Distribution System Faults and Wildfires: Mechanisms and Prevention. Forests , 14 (6), 1146. Douglass, D. A., & Thrash, F. R., 2018. Sag and tension of conductor. In Electric power generation, transmission, and distribution (pp. 15-11 15-42). CRC Press. Du Plessis, P., 1994. Mechanical oscillations on overhead transmission lines . University of Johannesburg (South Africa). Kiessling, F., Nefzger, P., Nolasco, J. F., & Kaintzyk, U., 2014. Overhead power lines: planning, design, construction . Springer. Lee, S., & Ham, Y., 2021. Probabilistic framework for assessing the vulnerability of power distribution infrastructures under extreme wind conditions. Sustainable Cities and Society , 65 , 102587. Liu, Y., Xv, J., Yuan, H., Lv, J., & Ma, Z., 2018. Health assessment and prediction of overhead line based on health index. IEEE Transactions on Industrial Electronics , 66 (7), 5546-5557. Naranpanawe, L., Ma, H., Saha, T. K., Lee, C., & Ghosal, A., 2020. A practical health index for overhead conductors: experience from Australian distribution networks. IEEE Access , 8 , 218863-218873. Naranpanawe, L., Ma, H. and Saha, T., 2018. Overhead Conductor Condition Monitoring–Milestone Report 1 . Otero, A. F., Vilacha, C., Moreira, J., & Miguez, E., 2012. Electrodynamics simulation of overhead power lines. IEEE transactions on power delivery , 27 (2), 560-567. Polevoy, A., 1998. Calculation of sag changes caused by conductor beating with consideration of insulator string deviation in a transmission line section. IEEE transactions on power delivery , 13 (4), 1238-1243. Riba, J.-R., Liu, Y., Moreno-Eguilaz, M., & Sanllehí, J., 2022. On-Line Core Losses Determination in ACSR Conductors for DLR Applications. Materials , 15 (17), 6143. Than, T. T. M., 2023. Research and Development process in replacing Aluminum Conductor Steel Reinforced cable. Vasquez, W. A., Jayaweera, D., & Játiva-Ibarra, J., 2017. End-of-life failure modelling of overhead lines considering loading and weather effects. 2019 IEEE International Conference on Power, Electrical, and Electronics and Industrial Applications (PEEIACON), Zainuddin, N. M., Rahman, M. A., Kadir, M. A., Ali, N. N., Ali, Z., Osman, M., Mansor, M., Ariffin, A. M., Rahman, M. S. A., & Nor, S., 2020. Review of thermal stress and condition monitoring technologies for overhead transmission lines: Issues and challenges. IEEE Access , 8 , 120053-120081.