Passive protection limits: a parametric analysis of arcing horn efficiency under high grounding resistance

Objective. This study aims to determine the physical and economic limit of passive arcing-horn protection under high tower footing resistance (TFR), and to define the grounding threshold beyond which utilities should transition from passive geometric retrofitting to active transmission line arresters (TLAs) in high-isokeraunic tropical environments. Methods. This paper presents a detailed parametric analysis of arcing horn efficiency using PSCAD/EMTDC simulations driven by a 15-year local lightning dataset. By subjecting a 275 kV double-circuit tower model to both standard and severe tropical fast-front lightning waveforms (0.25/100 µs), a definitive performance ceiling of passive protection is identified. A novel gap efficiency (ηgap) metric is proposed to quantify this saturation point, helping utility planners understand the physical limits of passive measures. Results. Results show a clear saturation point: when TFR exceeds 20 Ω, extending the arcing horn beyond 2.55 m yields negligible improvements to critical current, dropping gap efficiency below 40 kA m−1. Furthermore, under fast-front strikes, massive inductive voltage rises render gap adjustments entirely ineffective. This vulnerability sustains a critical Backflashover Rate of 16.51 outages/100 km/year. Conclusion. To address this, a Grounding-Dependent Decision Framework is introduced that clearly defines the threshold at which utilities must transition from passive retrofitting to active protection devices, such as TLAs. This threshold guides protection strategy decisions based on soil and lightning conditions, ensuring timely upgrades.

Text 127975.pdf - Published Version Available under License Creative Commons Attribution. Download (1MB) Official URL or Download Paper: https://iopscience.iop.org/article/10.1088/2631-86...

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