Power sharing systems are becoming increasingly popular for sharing power over long distances between different electricity suppliers. Sometimes known as interconnector projects. These systems pose a risk to the integrity of buried pipelines.

Accelerated corrosion of buried pipelines due to electrical interference is an ever-present risk. High Voltage AC (HVAC) systems such as overhead and buried powerlines can accelerate corrosion and generate unacceptably high touch voltages on above ground pipeline appurtenances.

AC railways (typically 25 kV) cause the same problems where there are long parallelisms with pipelines.

Direct current systems (DC) can also have a deleterious effect on pipelines by accelerating corrosion. Obvious sources of DC interference are metro systems, trams, DC traction systems and industrial activities such as welding.

Less obvious sources of AC and DC interference to buried pipelines are industrial scale solar farms, wind turbines, space weather (geomagnetic effects) and battery energy storage systems (BESS).

Another source of DC interference is the HVDC interconnector power sharing systems that feed high currents over long distances between suppliers (often in different countries). Voltages greater than 300 kV are common with currents of up to a 1000 A DC under normal operating conditions. Assessing the corrosion risks from these systems is not straightforward. It requires knowledge of the HVDC system configuration and how the DC is converted back to AC.

This paper provides an explanation of the corrosion phenomena and how the effects of HVDC systems can be assessed against the provenance of a standard. The paper assumes no previous technical knowledge and is intended for non-specialists. It will enable risk and integrity specialists to understand the significance of electrical interference on pipelines.