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.

𝑅_𝐿 — Linear Electrical Resistance of the Section of the Pipeline(ohm/m)
𝑅_𝑇 — Leakage or Transverse Resistance of the Section of the Pipeline(ohm/m)
𝑅_𝐾 — 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)
𝐷_𝑜 — External Diameter of the Pipeline(m)
𝐷_𝑖 — Internal Diameter of the Pipeline(m)
𝐴_𝑤 — Pipe Cross Sectional Area(,in-2.)
𝐸₀ — Pipe to Electrolyte Potential at the Drain Point(Anode)(V)
𝐸_𝑥 — 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)
𝐼_𝑥 — 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

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

View the results.
If an input parameter needs to be edited be sure to hit the CALCULATE button after the change.
To SAVE, fill out all required case details then click the SAVE button.
To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
To generate a REPORT, click the REPORT button.
The user may export the Case/Report by clicking the Export to Excel/PowerPoint icon.
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

Cathodic Protection Module Attenuation Calculation

Input Parameters

Outputs/Reports

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