Is Our Pipeline Adequately Protected From AC Corrosion?

May 15, 2020

By Jamey Hilleary 

Over the past two decades, corrosion attributed to AC interference from high voltage power lines has emerged as one of the most daunting challenges facing pipeline operators. Why? Because AC interference produces rapid, aggressive corrosion - even on well-coated pipelines, and it can be very difficult to detect, evaluate and mitigate.

In recent years, many pipeline companies have worked to address problems caused by AC interference. They’ve invested a lot of time, money and resources to evaluate the risk and have deployed mitigation systems designed to reduce or eliminate the corrosion risk AC presents. The effectiveness of their efforts, however, depends on a number of variables, including the volatility of AC interference, pipeline coating, soil resistivity, current load on the high voltage transmission lines and proximity of the pipeline to the high voltage lines. With these factors and more in play, it’s no wonder that many companies continually question whether or not their AC mitigation efforts are truly eliminating the corrosion risk.

In 2018, NACE International published its first standard dealing with the corrosion risk of AC interference.  This new standard (NACE SP21424) defines AC voltage and current limits that need to be adhered to, as well as specific conditions in regards to the interaction of AC and DC current density levels. Most of these limits were previously adopted as “best practices” by many pipeline operating companies.  In addition to the current and voltage limits, corrosion rate is now also included as a means through which compliance may be demonstrated.

The Elecsys Tracker CR was specifically developed to provide pipeline operators with all of the data necessary to assure compliance to the new standard and to ensure mitigation effectiveness for pipeline integrity management. Built on the same monitoring platform as the very successful Tracker B system, the Tracker CR provides standard test station cathodic protection measurements such as pipeline “On” and “Off” voltage potentials and measures AC voltage, AC and DC current densities and AC drain to ground. The Tracker CR takes this concept one step further, providing corrosion rate measurements using a custom-designed 1cm² electrical resistance (ER) corrosion probe. The Tracker CR, with its custom-designed coupon/reference electrode ground probe, is a cutting edge solution for all AC interference and mitigation monitoring applications. 

The Tracker CR uses our state of the art, reliable field hardware to communicate via cell or satellite to the unparalleled Elecsys Connect web portal and mobile apps. The data recorded by the monitoring unit is available at the user’s fingertips, 24/7, from any web-enabled device.

Gone are the days when one had to deploy data-logging devices at remote locations only to discover the batteries had failed before recording sufficient data for effective analysis. Gone are the headaches due to unreliable monitoring systems and difficult to navigate data interfaces. With the Tracker CR, you will have all the information you need to know that your pipeline is protected from AC corrosion.

For more information about Tracker CR, visit our website or talk to Jamey Hilleary