Abstract
One of the challenges facing corrosion professionals is the co-location of pipelines with other sources of interference in congested urban and suburban right of ways. It is often difficult to determine the source(s) of interference currents so mitigative action can be made to restore sufficient cathodic protection on the affected pipeline. Evaluating the effects of electric transit systems can be a particularly difficult task when the interference is significant only in short intervals. Additionally, multiple data parameters including: AC and DC potentials, AC and DC current densities, and reverse current switch measurements should be gathered synchronously to build an accurate profile of the total interference being experienced. Data-logging at locations of high detrimental DC traction interference can be effectively used for evaluation however; time synchronization of the data events across multiple sites is not always accurate if the proper equipment is not employed.
This paper is a case study on the use of web-based monitoring systems with remote data-logging capability to acquire critical data and develop interference profiles on pipelines originating from electric transit systems. The focus is on accomplishing effective synchronization of time-based events, across multiple sites, and correlating the data back to the intermittent transit system events which are causing the interference. An additional challenge is identifying other foreign current sources not directly associated with the transit system which may also potentially contribute to, or distort the interference profile.
