Influences of faulty AC underground power cables on the neighbouring metallic gas pipelines

Abstract

In this paper the impacts of faulty underground power cables on their neighboring metallic buried pipelines have been investigated, specifically in the event of line to ground faults of these cables, as well as the use of barrier mediums to reduce this effect. In this paper, the conduction current generated in metal pipeline as a result of faults in underground cables is studied.To reduce the induction voltages affecting the metallic pipelines, it is proposed to use a barrier between the cable and the metallic gas pipes. The effects of the type of barrier material, its thickness, and its distance from the cable on both the induction voltages and currents generated in the metal pipes are investigated. It is found that the use of XLPE barrier with thickness of 5 mm at 600 mm space from the pipeline reduces the induced voltage to be 40.02 % - 40.6 % of its value when concrete barrier is employed and 98.6 % - 98.5 % with the use of copper barrier respectively. Similar results proved that the increase of the barrier thickness is effective in reducing the induction voltage. The metal barrier has proven to be the best in reducing the effect of the induction voltage resulting from the line to ground faulty underground power cable on the neighboring metal pipes.