Induced electromagnetic field on underground metal pipelines running parallel to nearby high voltage AC power lines

High voltage AC (HVAC) power lines can induce significant amount of voltages on underground gas/oil metal pipelines in areas where they share similar Right of Way (RoW), the situation becoming serious particularly in case of fault conditions. Electromagnetic field generated by the HVAC power lines on these pipelines, generate unwanted voltages which present threats to the pipeline and its associated protective equipment such as cathodic systems. The aim of this research is to compute induced voltage on pipeline running parallel to HVAC power lines. The study was conducted using CDEGS software package and revealed that under steady state condition, results were in agreement with GB 6830-1986 standard. However, high currents are generated under single phase to ground short circuit rising the potential of adjacent soil including the underground pipeline beyond limits. Therefore, the gradient control wire mitigation technique is proposed to reduce these voltages to safe limits.