Impact of High Voltage Overhead Lines on Pipeline Security

The changing focus of energy politics to renewable energy and the
constantly rising demand for energy has been leading to the development of existing
high voltage stations, overhead power lines and cables as well as to the construction
of new equipment for the transportation of additional current load. Therefore, the
conductive and inductive interference near buried isolated metallic pipelines is rising
which causes an increase in AC pipeline interference potential. This has an impact
on the operation of pipelines. Increased voltages on a pipeline are a danger to
people and pipeline system components. In addition, the higher inductive
interference may raise the AC corrosion risk on the pipeline itself. In this case higher
inspection and maintenance costs arise because of material corrosion and, in a worst
case scenario, it may cause an additional threat to the environment.
Within Austria and Europe exist standards and guidelines (EN 50443 [1],
EN 15280 [2]) which limit the maximum voltage for long term and short term
interference. If the pipeline interference voltage is within the limits no further actions
are required and no further costs are generated.
With newly built or extended high voltage overhead lines the maximum current for
normal operations and short-circuit-situations can increase fundamentally. A precise
method is needed to calculate the inference potential of a pipeline to find (only) the
necessary measures for pipeline protection to avoid endangering people and material.
It can be shown that the positioning and, for long term interference, the overhead line
phase conductor arrangement are decisive factors when calculating the inference
potential. Current mathematical models and software simulations show that varying
pipeline coating and the ambience specific soil resistivity may cause a big fluctuation
in the pipeline interference voltage.