Regional cathodic protection (CP) system is used to protect buried facilities in oil/gas stations from corrosion caused by soil and electrical grounding system with electropositive materials. However, the required current may increase tens to hundreds of times due to the existing electrical grounding materials, and extremely heterogeneous protected potential distribution on buried facilities may occur. To analyze and improve the compatibility of regional cathodic protection system and electrical grounding system in oil/gas stations, numerical simulation was used to calculate the potential and current distribution based on different cases with: (1) electrical isolation between grounding system and CP system; (2) different electrical grounding materials; (3) Optimization of anode beds with near/remote anode beds; (4) isolation of partial grounding electrodes. The results showed that the lower spacing including intersection between buried structures and grounding electrodes were the main cause of incompatibility. Isolation of the entire horizontal grounding electrodes and optical design of anode beds with numerical simulation technique could improve the CP effectiveness. Moreover, electrical isolation between grounding system and CP system or using electronegative materials like zinc anodes as electrical grounding materials are effective in some situations.

Subject
Materials, Galvanic anodes, Anode potential, Cathodic protection, Zinc anodes, Pipelines, Grounding, Anodic current, Below ground pipelines, Copper, Electrodes, Electrode potential, Anodes
Keywords:
cathodic protection, electrical grounding, oil/gas stations, numerical simulation
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2017
Association for Materials Protection and Performance (AMPP)
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