Cathodic protection of submarine pipeline

The cathodic protection of submarine pipeline is very long because of its high cost. Those pipelines with short distance adopting impressed current cathodic protection adopt built-in measuring electrode. For submarine pipeline, the following four methods can be used to monitor the effect of cathodic protection.



① Magnetic induction method. When a probe passes through the pipeline, it can obtain the current flow measured by magnetic induction method, the function of the actual anode to be measured, the defect area detected, etc., and the increased current can be recorded at the defect position and on the anode installed at a certain distance. Now this method has been used frequently.



② Electrode with remote data transmission function. The technology of potential probe has been developed. The probe can be moored near the pipeline by buoyancy float and connected with the pipeline electrically. These probes can only be activated by code signals from the survey ship. They read out the potential values and transmit them back to the survey ship by sonar technology. The probe batteries must be replaced regularly, which requires a large number of probes, and they are in danger of being damaged by the trawl.



③ The potential difference between the reference electrodes was measured. According to this method, the reference electrode is attached to the power supply cable of the remote control car. There are two electrodes on the trolley. When the trolley moves along the pipeline, according to the potential difference data between these electrodes, the effectiveness of sacrificial anode, the location of defects, current interception, and electrifying potential can be explained.