Pipe-to-Soil Potential Modelling in the UK Gas Transmission Network

Abstract:

Large geomagnetic field variations during geomagnetic storms induce telluric currents in pipelines. These currents can lead to variations in the pipe-to-soil potentials (PSPs) which interfere with corrosion-prevention measures and may therefore enhance corrosion, leading to localised damage and a reduced lifetime of the pipeline. Modelling PSP fluctuations is useful for mitigation measures in existing pipelines, as well as at the design stage to allow new pipelines to be built to withstand such impacts.

We present a first attempt to build capability for modelling these currents in the high-pressure gas pipeline network of the United Kingdom. We use the method of Boteler (GJI, 2013, doi: 10.1093/gji/ggs113) and modify our existing UK high-voltage (HV) electrical network code to account for the continuous grounding of the pipelines. We use open source data to create the pipeline network, splitting each pipeline into straight-line segments where we can assume a constant surface electric field within each section. We present results from our pipeline models for both uniform and storm-time electric fields and discuss the results.