IEC has in its portfolio insulation joint protection devices manufactured by Dairyland Electrical Industries, DEI.
The pipeline joints may be subject to overvoltage faults due to lightning and, in some applications, AC voltage. When a pipeline is near from electric transmission line, it may be subject to significant AC voltage if a fault occurs. Overvoltage protection against lightning and AC failure conditions occurs while maintaining the cathodic protection of the pipeline insulation joints. This is possible using classified products through proper choice of the device and the location of the device installation. Adjacent pipelines and installations should be examined to establish a complete protection scheme.
The protectors also referred to as decouplers, drain alternating current and block direct current in the main applications:
– Protection of Insulating Joints: Installed in parallel to the joints, the decouplers allow the passage of AC currents coming from lightning strikes or high voltage lines in case of short circuits or in continuous regime;
– Mitigation of AC voltages from high voltage lines: The best way to reduce these voltages is to ground the pipeline, but this would make cathodic protection unfeasible. The decouplers allow to connect the pipeline to the ground without damaging the cathodic protection as they drain the AC currents and block the DC.
– Grounding of valves and stations connected to pipelines;
– Grounding of tanks with cathodic protection;
– Temporary landings of vessels in ports;
– Among others.