Sacrificial anode cathodic protection will be more negative potential of metal to be protected metal connection, and electrolyte in unity, make the electron transfer to the protected metal on metal, make the whole protection of metal in a more negative, under the same potential of the method is simple and easy, don't need additional power supply, rarely cause erosion, Widely used to protect small (current less than 1 ampere) or in low soil resistivity environments (soil resistivity less than 100 ohms). Meters) of metal structures, such as city pipe networks, small storage tanks, etc.

Impressed current cathodic protection is an applied DC power source and an auxiliary anode that forces current from the soil to the protected metal, making the structure of the protected metal less potential than the surrounding environment. This method is mainly used to protect large or high resistivity soil in the metal structure, such as: long buried pipeline, large tank group, etc.