Grounding resistance of auxiliary anode grounding bed

Impressed current cathodic protection is mainly used in long-distance pipeline, gas transmission and distribution pipeline, pipeline in industrial device, and other buried devices with large protection current. The grounding resistance of auxiliary anode is the largest resistance unit in the protection circuit. When the protection current is large, the grounding resistance of auxiliary anode determines the voltage required by rectifier and the power of cathodic protection station. In order to reduce power consumption and operation cost, the design of grounding resistance should be as low as possible. The anode bed with protective current output greater than 1A should be arranged at the place with the lowest soil resistivity. At present, the anode bed in deep well is usually backfilled with continuous coke slag, which is set horizontally or vertically.


The protective current flows into the soil through the auxiliary anode bed. Therefore, the electric field intensity, current density and voltage gradient per meter length around the anode bed are maximized, and these parameters decrease with the distance from the bed. Although the protective current can be detected at a certain distance from the anode ground bed, there is no obvious field strength. This potential is called the voltage between the distant earth and the anode, which is called anode voltage. Since the soil surface has a cone-shaped voltage distribution curve, this is also known as the voltage cone of the anode bed. The height of the voltage cone depends on the anode voltage and its shape depends on the anode arrangement. This is important for possible impacts on buried external installations.


Voltage cones are also generated when the protective current flows through the coating defect and enters the pipe.


Shandong Linyi Bosi conductive materials Co., Ltd. is a high-tech enterprise specializing in the production of MMO flexible anode, conductive polymer flexible anode and titanium coated anode, mainly providing cathodic protection technology, engineering design, installation and technical services.