Direct Current Voltage Gradient

Direct Current Voltage Gradient (DCVG) Survey is a survey
technique to evaluate the coating condition on buried pipelines. The
principle of this technique involves detecting a voltage difference on
the earth surface just above the buried pipeline by using two or more
portable reference electrodes separated by a short distance. In a
DCVG Survey, a DC Signal is typically created by interrupting the
pipeline's Cathodic Protection current, and the voltage gradient in the
soil above the pipeline is measured. Voltage gradients arise as a result
of current pickup/discharge at coating defect locations.

- Above Ground Survey
- Coating Defect Location
- Foreign Contact Location
- Coating Defect Severity