Cathodic Protection

Electrical Short Pipeline Potential Measurement and its Implication in Pipeline CP Management Practice

This is a paper published in Corrosion Management Magazine ( September 2018, issue 145). It can be accessed from IoCC website. The most important performance indicator for cathodic protection (CP) is the structure-to-electrolyte potential. In most of coated on-shore pipeline, the resistance between the reference electrode and the pipe-to-soil surface boundary is too significant to be ignored.  The IR drop caused by CP current is a measurement error. It is stipulated in many CP standards that IR component to be evaluated and excluded while assess the pipe-to soil potential performance in pipeline integrity management. For a well-coated pipeline, the most…
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Cathodic Protection Numeric Method Summary Report

By Bowen Xu The project is object to build and solve a mathematical model using a numerical technique by Boundary Element Method (BEM) for corrosion analysis. At the end, the project is not completed successfully. Reasons are discussed and possible future improvement is outlined. To investigate what went wrong during the project, firstly, we have to know a certain amount of physics and chemistry concepts that underlie the mathematical model.

Cathodic Protection Numeric Simulation

Cathodic protection monitoring is a most common practice for the assessment of effectiveness of corrosion protection.  However, metal loss due to corrosion is somehow evident even on pipes are deemed to be well protected based on standard monitoring and survey techniques.  The effectiveness of the the field survey techniques are further questioned for the structures within the common corridor with multiple functioning cathodic protection systems in place. Numeric simulation provides better opportunity to understand the pipe potential as current density along the structure. This, along with standard survey practice, renders a clear picture of the effectiveness of the cathodic protection….
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Cathodic Protection Data Visualisation

One issue in Cathodic Protection (CP) Management is to handle large amount of data. Some specialised programs are available in the market with premium price. We are not discussing those data package, which are normally having lots of redundant functions. In CP daily management, one typical task is to visualise and comparing the data logging data from different test posts recorded in the same time. people will normally use spreadsheet such as MS EXCEL to plot the data. However, MS do have the limitation of 32,000 data point for each dataset, which is often not sufficient in CP data logging….
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Off-Potential Interference by Solid State Decoupler

Electrical Circuit for Off-Potential Measurement without SSD Electrical Circuit for Off-Potential Measurement with SSD What Happens while Measuring Off-Potentioal with SSD Connected When CP current (S1) is interrupted: The voltage across decoupler must change by the Icp x Rp voltage drop component that was eliminated A transient current must flow to make this voltage change Until this transient current is dissipated, an Off Potential measurement will not be measured accurately(too electronegative). How to Measure Off-Potential with SSD OFF waveform analysis with a longer than normal On-Off cycle (e.g. 7 On, 3 Off) Determine the time after current interruption where a…
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