Ac Induced Corrosion Assessment of Buried Pipelines Near Hvtls: A Case Study of South Africa

Abstract

Metallic pipelines have attendant problems of alternating current (AC) assisted corrosion when installed in the utility corridor with high voltage transmission lines. Research studies in the past and recent years have shown that this corrosion is a primary function of the AC density through the pipe coating defect. While several other AC corrosion risk assessment indices have been proposed, the AC density is regarded as a valuable parameter in assessing pipeline corrosion risk due to AC interference. Also, there exists a threshold value which, if exceeded, guarantees the possibility of pipeline corrosion damage. However, for buried pipelines, monitoring these AC corrosion assessment indices is a major challenge. Therefore, to avoid severe corrosion damage to such pipelines, a corrosion assessment for evaluating the corrosion risk of the pipelines due to AC interference is presented in this paper. The assessment was demonstrated on a buried pipeline in one of the Rand Water sites, South Africa where AC interference is frequent. The overall simulation results yield useful information which may be essential for pipeline operators, most especially Rand Water, South Africa and corrosion engineers for AC corrosion assessment of metallic pipelines installed near transmission lines. The analysis presented in this paper may also be used for the evaluation of a safe position for installing new pipelines near existing power lines right-of-way.

AC corrosion of steel pipeline under cathodic protection: A state‐of‐the‐art review

“…Through numerical modeling, the magnitude of AC current density can be calculated on the basis of theoretical equations. For example, Adedeji et al [98] developed a numerical model using MATLAB to determine the high-voltage transmission lines induced AC current density and voltage on pipeline considering the soil conditions, transmission lines, and pipeline parameters, which provided a method to determine the inputs for laboratory experiments under different scenarios.…”

“…Through numerical modeling, the magnitude of AC current density can be calculated on the basis of theoretical equations. For example, Adedeji et al [ 98 ] developed a numerical model using MATLAB to determine the high‐voltage transmission lines induced AC current density and voltage on pipeline considering the soil conditions, transmission lines, and pipeline parameters, which provided a method to determine the inputs for laboratory experiments under different scenarios. Zhang et al [ 99 ] employed COMSOL Multiphysics to investigate the effect of AC transmission lines on the cathodic protection of long‐distance pipelines through inductive coupling, and the results were compared with measurements.…”

AC Corrosion behaviour of aluminium and zinc sacrificial anodes in seawater

“…In recent years, with the development and application of offshore platforms, the construction of offshore wind farms and the development of marine fisheries, submarine cables have been laid on a large scale in China, resulting in long-distance parallel or multiple crossings of submarine cables and submarine pipelines, forming a long-distance shared corridor belt, the pipeline might suffer from AC interference from the power system [1][2][3][4]. AC interference could threaten the personal safety of workers, accelerate the AC corrosion of pipelines [5][6][7][8] and affect the corrosion behaviour of the sacrificial anodes used for cathodic protection of pipelines [9,10].…”

Ac Corrosion on Pipelines: Influence of the Surface Layer Soil Resistivity in Evaluating the Current Density by a Probabilistic Approach

“…These algorithms are mainly based on the transmission line model for both inducing and induced plants. Afterwards, other algorithms based on Finite Element Method (FEM) have been proposed [10][11][12][13], and more recently, some theoretical evaluations of the AC induced corrosion risk have been presented in [14,15].…”