Abstract

In shared corridors where pipelines neighbor high-voltage alternating-current (AC) transmission lines, AC interference studies are essential to ensure public and personnel safety and to protect pipeline infrastructure. Such a study was conducted for more than 30 km of co-located pipelines and overhead transmission lines in Canada, which predicted elevated touch voltages under both steady-state and fault conditions, as well as a risk for AC-induced corrosion under steady-state conditions. Based on this study, mitigation was recommended at many sites, which included using grounding systems, decouplers, dead-front test stations, and monitoring.

It has been suggested that the costs of mitigating for high touch voltage scenarios resulting from AC fault conditions may be disproportionate to the life-safety benefits that it provides. As a result, a risk-based assessment was proposed as an alternative to conventional mitigation strategies. The aim was to quantify the risk introduced to individuals from elevated touch voltages resulting from fault conditions, and to make mitigation decisions informed by compliance to risk targets.

As part of a previous phase of this work, a feasibility assessment was completed, focusing on the application and development of models used to estimate the risk associated with elevated touch voltages resulting from fault conditions and the impacts that mitigation would have on the risk. The result of this phase was the development of a framework and methodology to estimate the risk of AC fault induced hazards to a given site, both for members of the public and employees, that could be used to evaluate any given site in the gas transmission system.

This paper presents the outcomes of a pilot risk assessment, focused on the farm tap units in the gas distribution system, detailing the quantification of both the mitigated and unmitigated risks resulting from fault conditions. Through the assessment, alternative mitigation actions were justified, allowing for more efficient allocation of resources while maintaining adequate protection to workers and the public.

Authors:

Fujinaga, Daniel; McAllister, Lowell; Svitish, Aiden; Bloch, Dylan (ATCO); 

Publisher:

ASME The American Society of Mechanical Engineers
2026 International Pipeline Conference

Year Published:

2026

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