AC interference between co-located pipelines and high voltage AC powerlines can result in safety hazards to operating personnel and the public under powerline steady-state and fault conditions. Under steady-state conditions, AC voltages are induced on the pipeline via electromagnetic coupling. Under fault conditions, high AC […]
An AC interference study was conducted in 2019 following a utility development project that included constructing a new substation and upgrading approximately 24 km of new AC transmission powerline sections in Alberta, Canada. The study comprised six transmission powerlines owned by one utility and eight […]
The new NACE Standard SP21424-2018 provides a set of simple criteria for assessing the risk of AC corrosion on existing collocations between powerlines and cathodically protected pipelines. However, the task of developing design criteria for new collocations is left to the pipeline operators. This paper […]
A field study was conducted by Corrosion Service and TransCanada Pipelines to determine the influence of the AC current density and of the coating holiday size on the rate of AC corrosion. This field study involved burying steel coupons of three different sizes (i.e., 1 […]
This paper covers various methods for dealing with sources of errors affecting the accuracy of the Direct Current Voltage Gradient (DCVG) coating defect identification and sizing tool. Topics reviewed in detail include: eliminating the influence of local soil resistivity and varying pipe depth on the […]
The quality of the indirect inspection data is a critical factor in conducting a successful ECDA. It is therefore essential to increase the accuracy of the field data collection, to improve the data processing and to effectively present the results. This paper describes several challenges […]
The analysis of indirect inspection data is a critical factor in conducting a successful ECDA process. This paper covers two lessons learned recently when dealing with bonded pipelines along common rights-of-way and also with equalization currents. The “old” challenge of differentiating between “threat” related versus […]
