Remote cathodic protection for pipelines
By Archita Datta Majumdar
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Cathodic protection is an electrochemical method applied to prevent immersed or underground metallic surfaces from corrosion. This process is vital to managing and maintaining pipeline integrity across the petrochemical, gas and marine industries. They make it possible to carry out efficient distribution through high- and low-pressure modes.
The cathodic protection or CP levels need to be regularly checked and measured so regulatory and safety standards are never violated and accidents averted at all times. For a long time such checks were done manually. Only recently are automated checks being placed for advanced protection. Remote cathodic protection has been introduced to ensure this process is fine-tuned even further.
To understand this process, it is important to know what cathodic protection is and how it works. One way pipeline operators ensure protection from corrosion is applying high-quality coatings that will restrict the environmental impact and interaction. Even then, defects are known to occur, which has given rise to the need for secondary protection like CP.
In CP, electric current (DC) is applied in small amounts to the protected surface to counteract the corrosion currents that exist or occur on the surface of the metal. The entire structure that lies under this metal surface is made to act like a cathode, which has given it the name of cathodic protection. Corrosion usually affects the anode rather than the cathode. That is why an external anode is connected to the metal in question while a positive DC current is passed through them. This turns the metal into cathode and prevents it from corrosion.
Even though they have been instrumental in cathodic protection, manual checks and measurements have certain disadvantages:
In a remote cathodic protection system, the output voltage as well as current transfer from a transformer is closely monitored so that the correct level of CP is always applied. Care is also taken to ensure that preset thresholds for DC and AC are constantly maintained so power outages can be reported immediately and contained.
Monitoring also includes anticipating and checking on electrical sources and power lines that can easily accelerate the corrosion pace of the pipeline. Remote monitoring works very well for impressed current systems but is also quite effective on galvanic or anode-based CP systems. In each case, the field data is sent to a centralized operational hub where it is processed and studied for discrepancies so all problems can be thwarted and taken care of even before they occur.
Key functions of remote cathodic protection:
Manual checks require periodic measurements at locations, both roadside as well as in inaccessible terrains. It also has increased risks of accidents and electrical hazards for technicians involved, not to mention the sheer cost involved in the operations. Along with worker safety, it also leads to better fulfilling of environmental obligations. With remote cathodic protection the operational lifetime of the pipeline is not just extended but works at an extremely cost-effective rate as well.
Web-based remote cathodic protection systems have now made it possible to administer and monitor CP levels in remote and difficult terrains easily. This is now being deployed across industries — utilities, water and wastewater industries, and of course for oil and gas pipelines. These are extremely reliable and accurate, which means maximum protection of the pipeline can be ensured. Real-time data collection and monitoring at low-cost operations means long-term cost effectiveness for business as a whole.
Archita Datta Majumdar has been writing for various industries for more than 14 years. She has contributed articles to The Economic Times, the leading financial daily of India, and she loves research, business analysis and knowledge management, which paves the way for a steep learning curve.