How to mitigate interferences between pipe protected and earth system

[jucagua77]

We have some block valve facilities installed along the 24” crude pipeline and the electric actuator of the valve is connected to earth grid of 15 meters long and 15 meters wide located 1.6 meters below the protected pipe.
The potential measure between pipe (inside the concrete walls) and soil is below of -850 mV only around valve area while the other potentials at 20 meters to both sides of valve have the normal protection value.
Which accessorie(s) should we install in those valve facilties to mitigate the interference of the earth grid??

 

[SJones]

If the earth grid is copper, ideally, change it to galvanised steel. If it can't be changed, investigate the sizing with a view to getting it to the absolute minimum for safe operation.

Steve Jones
Materials & Corrosion Engineer

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