Effect of increasing energy demand on the corrosion rate of buried pipelines in the vicinity of high voltage overhead transmission lines

There are continuous cases of pipelines sharing corridor with high voltage overhead transmission lines (HVTLs) both in rural and urban areas due to economic reasons, increasing energy demand, environmental factors and land use regulations. There is induction of voltage on the pipes due to inductive, capacitive and resistive coupling between the pipelines and the HVTLs, which accelerate corrosion of pipes. In this work, we present the effect of increase in energy demand on the corrosion rate of buried steel pipelines in the vicinity of HVTLs. The corrosion penetration rate of a buried pipeline with variations in the line current of a nearby overhead single circuit transmission line of vertical geometry was computed using existing relations from literature. The results obtained showed that increase in line current increases the corrosion rate of the pipeline. It can therefore be inferred from the results that a pipeline sharing corridor with transmission lines in urban cities and industrial areas where the energy demand is high will experience greater corrosion than those in rural areas where load demand is less, assuming the same condition of soil resistivity and its composition. Also, AC corrosion mitigation system and cathodic protection criteria need to be reviewed from time to time to meet the trend in energy demand.