Measurement of the Off Potential and Depolarization Process of Buried Pipelines with Test Block Power Interruption Method

The test block power interruption method is an effective way to measure the cathodic protection potential. There was a impressed-current cathodic protection system for buried pipeline in the laboratory, and the test block power interruption method was applied to test the off potential and depolarization process of the buried pipeline. The experimental results showed that the off potential should be recorded at 50~100 ms after cutting off the power supply. If the potential difference-value between the off potential and depolarized potential matches the 100 mV cathodic protection criterion, the cathodic protection is valid, otherwise the pipeline will corrode.