Final answer:
In DCVG technique, a current interrupter is installed in an existing rectifier unit or a temporary CP system is used. The rectifier converts alternating current into direct current useful for testing DCVG. The current interrupter switches the CP system off/on in specific intervals allowing the changes in the voltage to be measured.
Step-by-step explanation:
In regards to DCVG (Direct Current Voltage Gradient), this technique is accomplished by installing a current interrupter in an existing rectifier unit or by using a temporary CP (Cathodic Protection) system. Here, the rectifier is a key element of the DCVG system which converts alternating current (AC) into direct current (DC) useful for testing DCVG. A current interrupter is used to switch the CP system off/on in certain intervals, which allows the changes in the voltage to be measured.
Gauging the changes in the natural DC voltage gradient that exists around a buried pipeline is the key function of the DCVG technique. Any changes in this voltage signify a problem area where the coating around the pipeline may be damaged or non-existent.
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