Cathodic Protection

Cathodic protection (CP) is a technique used to protect metal surfaces from corrosion. It is achieved by placing an electrical current on the metal surface so that the metal becomes the cathode of an electrochemical cell. A simple technique of protection uses a “sacrificial metal” as the anode, which is connected to the protected metal. The sacrificial metal corrodes instead of the protected metal as a result. To ensure that passive galvanic cathodic protection is adequate for long pipelines, where no internal DC electrical power source is available, an external DC electrical supply is utilized.