From a cathodic protection point of view the VRESAP pipeline is a continuous steel conductor with little electrical resistance over 114KMs submerged in a common electrolyte with other conductors such as pipelines, railways and earthing systems..
There are 9 transformer/rectifiers, each providing 50 volts potential difference and limited to 50 amps current discharge into the ground.



This is a link to a more detailed description of the CP circuit.

Cathodic protection works like a battery charger and stops corrosion where there are more charges in the earth than are caused by the corrosion reaction Electro-Motive Force (EMF). The intention is to drain charges from the pipeline and impress them into the earth. We need to measure the effect that this has on corrosion at each coating fault along the pipeline. There is nothing in the specifications to suggest a realistic way gathering data that can achieve this measurement.

This is a link to a detailed explanation of this subject.

It should be possible to stop all corrosion by adjusting the transformer/rectifiers in balance with the zinc ribbon anodes and earth mats.

This is a link to pages about the groundbeds

There are three railways crossing the pipeline and these could provide conductive paths limiting the spread of protection.

This is a link to details of the effects of the railways on the pipeline.

There are zinc ribbon anodes located where overhead power lines run close and parallel to the pipeline The concept and actual function of these zinc ribbons should be fully investigated as it is possible that AC charges could be induced into the zinc. The mitigation of AC seems to have been attributed to strip anodes without scientific testing or real justification as discharge of AC is easily achieved using magnesium sacrificial anodes at locations where the ground potentials are lower than those in the proximity of power lines or railways.

This is a link to pages discussing this topic

The specifications for the cathodic protection of the VRESAP pipeline require compliance to DIN 50918 and the drawing of the 'IR Free Reference Electrode' is not a method of applying DIN 50918 in the field. The data gathered from the specified reference electrode and coupon arrangement is incapable of defining the corrosion status of this pipeline.

This is a link to a detailed examination of this topic.

The CP reports describe micro-amps and current densities using graphs based on 24 hour current logs and this data cannot be used to estimate the corrosion activity or status of any part of the pipeline. This is a link to a detailed examination of this topic.

There is no description of the method of conducting a 'bulk CIPS and DCVG survey' but an explanation of the actual procedure (given by a field worker) does not include either type of survey. The monitoring on this pipeline is restricted to recordings of voltages and current at each test facility and this cannot render data that can define the corrosion status between these locations.

This is a link to a detailed examination of this topic.

The pipeline specifications refer to coating that shall be fault free. If this was achieved it would be a world first and the specification is irrational but begs the question of the specification for cathodic protection which only affects coating faults.

These two specifications are in conflict with each other.

The coating has been found to peel off at certain locations and

this is a link to some information on this subject.

The coating condition is being ascertained by a method called PCM

and this is a link to an appraisal of that.

These specifications refer to some codes of practice that are intended for other scientific activities and an explanation should be sought.

The specification of the experience in manufacture of the reference electrode and coupon system is entirely unnecessary as the product itself can be examined in detail for compliance. It is technically irrelevant how it was made and by whom.