SF₆ leakage risk in gas-insulated switchgear under the interaction of ageing and environmental stress

Alomari, Majdi M., Bani-Mustafa, Ahmed, Dirawieh, Abdel-Wahab B., Alshdaifat, Nafesah I., EL-Kanj, Hania, Topal, Ayse and Alhalaili, Badriyah 2026. SF₆ leakage risk in gas-insulated switchgear under the interaction of ageing and environmental stress. Results in Engineering , 109929. 10.1016/j.rineng.2026.109929

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Abstract

Gas-insulated switchgear (GIS) is critical for high-voltage transmission networks but poses environmental challenges due to sulfur hexafluoride (SF₆) leakage, especially under hot-arid conditions. This study develops a unified Reliability–Environmental–Economic (REE) framework that integrates Bayesian Weibull reliability modelling under fully right-censored data, composite environmental stress decomposition, and probabilistic leakage estimation for Kuwait’s 132–400 kV GIS fleet. Results indicate a weakly increasing age-dependent hazard regime (β > 1), with environmental stress (temperature, dust, salinity, and humidity) emerging as the dominant driver of leakage variability. Fleet-level analysis estimates baseline SF₆ leakage at ≈6.24 t yr⁻¹ (≈1.52 × 10⁵ t CO₂-eq yr⁻¹, IPCC GWP100). Stress-mitigation and partial replacement scenarios reduce emissions growth but cannot eliminate long-term risk. Cooling retrofits yield moderate reductions by lowering temperature-driven stress, while partial replacement with SF₆-free technologies achieves larger reductions by structurally removing leakage sources. Economic evaluation using discounted cash-flow analysis (3–8% rates) demonstrates that SF₆-free replacement, despite higher upfront capital costs, achieves competitive abatement efficiency due to sustained emissions elimination over time. These findings highlight that age alone is an unreliable indicator of GIS performance. Instead, stress-informed, risk-based modernisation strategies, combining probabilistic reliability modelling, environmental exposure quantification, and economic trade-offs, are essential for effective transmission planning in hot-arid systems. The REE framework provides a transparent, data-driven basis for fleet-level screening and prioritisation, supporting Kuwait’s alignment with international climate commitments and regional sustainability initiatives.

Item Type:	Article
Date Type:	Published Online
Status:	In Press
Schools:	Schools > Engineering
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by-nc-nd/4.0/, Start Date: 2026-03-04
Publisher:	Elsevier
ISSN:	2590-1230
Date of First Compliant Deposit:	9 March 2026
Date of Acceptance:	4 March 2026
Last Modified:	09 Mar 2026 12:01
URI:	https://orca.cardiff.ac.uk/id/eprint/185601

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