Increase the resistance of the electrolyte by surrounding the structure with a high resistivity medium like a bed of dry sand.
Boost the metallic structure resistance by inserting insulating joints between distinct parts of the structure. However, for long pipeline structures that carry a conducting electrolyte, this must be done carefully, since the joints could be short circuited internally by the electrolyte and induce internal corrosion. In addition, this insertion of insulating joints may not be recommended, due to requirements imposed by the proper cathodic protection system. Of course, keep in mind that stray currents can still flow between two insulating joints.
Increase the metal/electrolyte interface resistance by painting or coating it. This technique is preferably applied to the cathodic zones, since otherwise there is the danger of high local current densities at the anodic zones that can result in rapid and severe failure through pitted attack. Of course, for long pipelines, it is impossible to predict the anodic and cathodic zones without solving the potential problem. Moreover, these areas can vary in time due to changing stray current characteristics (e.g. a moving train). Therefore, it is recommended to coat or paint the whole structure and use an additional cathodic protection system as back-up.
Enhance the (non-linear) polarisation behaviour of the metal/electrolyte interface by changing the characteristics of the electrolyte, using inhibitors or removing depolarisation agents and detrimental bacteria. However, this is very difficult due to the extensive dimensions and the intrinsic inaccessibility of buried structures.
Reduce the driving voltage Vsc by introduction of a back potential in the corrosion circuit. For structure corrosion prevention, this is an elaborate technique, since the back potential should be introduced into the soil. But for earth corrosion inhibition, an opposite
On the object of stray current corrosion see also: DC traction, Cathodic protection, Coating, Contour plots, Definition, Detection, Examples, External currents, Historical perspective, Impressed current, Interference, Mechanisms, Modeling. Pipeline, Potential distribution, Prevention, Stray fields and leakage, Transit systems
Study and Evaluation of Stray Current Influences on Cathodic Protection Systems of Buried Pipelines, L. Bortels, ELSYCA - Kranenberg 6 - 1731 - BELGIUM, ELSYCA