how the impress current anode funtion in cathodic protection?

Answer 1

Impressed current is protection from corrosion. Metals corrode when their atoms lose electrons. A DC power source has its positive terminal attached to a ground rod called the anode. Then its negative terminal is attached to your underground pipe or other metallic object. This forces an excess of electrons on the metal so that the atoms cannot easily lose electrons.

The potential, also called voltage, must be adequate or the protection will not be adequate.

P.S. The ground rod must be replaced periodically because its corrosion is accelerated by the current.