Direct Electrical Heating Closer to Subsea Structures

Direct electrical heating is a qualified method for flow assurance in
coated oil and gas flowlines. A concern is ac corrosion on connected
templates caused by stray currents from the DEH system. This has
prevented DEH from being installed on flowlines with in-line templates
and restricted heating of flowline sections near the end templates.
Solutions to limit stray currents have been verified by full-scale tests.
The results confirm a reduction in stray currents through templates to
3 % of the supply current by installing laminated iron cores on the
heated flowline.