Direct Current Voltage Gradient (DCVG) Survey

The Direct Current Voltage Gradient (DCVG) Survey is a survey technique to evaluate the coating condition of 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