Cathodic Protection Module Attenuation Calculation

Where long distances are covered by impressed current systems, voltage drops occur along the structure in a reduction fashion of voltages and currents.
Reductions can be significant depending on the current demand and voltage drops. This may require additional cathodic protection for the pipeline system.

𝑅𝐿 — Linear Electrical Resistance of the Section of the Pipeline(ohm/m)
𝑅𝑇 — Leakage or Transverse Resistance of the Section of the Pipeline(ohm/m)
𝑅𝐾 — Characteristic Resistance of the Section of the Pipeline(Ohms)
𝛼 — Attenuation Constant of the Section of the Pipeline(Ohms)
𝑅0 — Pipe to Electrolyte Insulation Resistance(Ohms)
𝜌 — Specific Resistance of the Pipeline Material(Ohms)
𝐿 — Half Distance between Drain Points(anodes)(m)
𝐷𝑜 — External Diameter of the Pipeline(m)
𝐷𝑖 — Internal Diameter of the Pipeline(m)
𝐴𝑤 — Pipe Cross Sectional Area(,in-2.)
𝐸0 — Pipe to Electrolyte Potential at the Drain Point(Anode)(V)
𝐸𝑥 — Pipe to Electrolyte Potential at the Distance of X from the Drain Point(V)
𝐼0 — Current Flowing onto the Pipe at the Drain Point(Anode)(amp)
𝐼𝑥 — Current Flowing onto the Pipe at Distance X from the Drain Point(Anode)(amp)

 

For typical pipeline with multiple drain points (anodes) with uniform spacing of 2L the potential and current are given:

Input Parameters

  1. To create a new case, click the “Add Case” button
  2. Select the Cathodic Protection Attenuation Calculation application from the Cathodic Protection module list.
  3. Enter Case Name, Location, Date and any necessary notes.
  4. Fill out all required fields.
  5. Make sure the values you are inputting are in the correct units.
  6. Click the CALCULATE button.

 

  • Pipe Outside Diameter
  • Pipe Wall Thickness
  • Half Distance between Drain Points (Anodes)
  • Specific Resistance of Pipeline Material
  • Pipe-to-Electrolyte Insulation Resistance
  • Pipe-to-Electrolyte Potential at the Drain Point
  • X – Distance from the Drain Point (Anode)

Outputs/Reports

  1. View the results.
  2. If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
  3. To SAVE, fill out all required case details then click the SAVE button.
  4. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
  5. To generate a REPORT, click the REPORT button.
  6. The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
  7. To delete a case, click the DELETE icon near the top of the widget.

 

  • Linear Electrical Resistance of the Pipeline Section
  • Leakage/Transverse Resistance of the Pipeline Section
  • Characteristic Resistance of the Pipeline Section
  • Attenuation Constant of the Pipeline Section
  • Pipe-to-Electrolyte Potential at the Distance of X from the Drain Point

Related Links

Table of Contents
Table of Pages
  1. Pipeline HUB User Resources
  2. AC Mitigation PowerTool
  3. API Inspectors Toolbox
  4. Horizontal Directional Drilling PowerTool
  5. Crossings Workflow
  6. Pipeline Toolbox
  7. Encroachment Manager
  8. PRCI AC Mitigation Toolbox
  9. PRCI Thermal Analysis for Hot-Tap Welding
  10. PRCI River-X
  11. PRCI RSTRENG
  12. RSTRENG+
  13. Ad-hoc Analysis
  14. Database Import
  15. Data Availability Dashboard
  16. ESRI Map
  17. Report Builder
  18. Hydrotest PowerTool
  19. Investigative Dig PowerTool
  20. Hydraulics PowerTool
  21. External Corrosion Direct Assessment Procedure – RSTRENG
  22. Canvas
  23. Definitions
  24. Pipe Schedule and Specifications Tables