Lightning and High-Voltage Interference Protection on Pipelines
Due to building regulations, pipeline sections are often installed in parallel with high-voltage lines electrified railway routes. This proximity poses the risk that A.C voltage transfers to the pipeline.
To prevent possible corrosion effects caused by
- Different soil conditions,
- Different free corrosion potential of different metals,
- Stray currents resulting from D.C traction systems and
- Induced A.C voltages,
The electrochemical corrosion process can be stopped by cathodic protection measures. This is achieved by galvanic anodes (sacrificial anodes) or impressed current systems which prevent the gradual material degradation at the steel surface by shifting the metal/ medium potential to more negative values and at the same time considerably reducing the corrosion rate.
Cathodic protection requires permanent monitoring of the pipeline. To this end, the voltage level at the pipeline is detected at defined measuring points along the pipeline and, if necessary, the intensity of the protective current is adapted. For this purpose, the pipeline is divided into individual segments which are electrically isolated from one another by insulating couplings (mainly underground) and insulating flanges (aboveground)Click here
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