Stray current from the cathodic protection system
An impressed current cathodic protection system can cause stray current interference in nearby pipelines, depending on the location of the ground bed, the exact location of the pipeline, and the operating characteristics of the cathodic protection system.
Interference test
Static DC stray current interference from cathodic protection systems is measured where no dynamic stray current from, for example, DC transmission systems is present. Suppose a detection device is installed at each point where an external pipe passes through, connecting each pipe to the detection device by two color-coded lines. An automatic current interrupter (a device that automatically opens or closes a circuit at a preset time) may be installed at the output of the rectifier. The break is set to 20m circuit on and 10m circuit off. When the current interrupter is working, it detects the external pipes passing through and measures the voltage of each pipe under both current on and current off conditions. For detection, the copper sulfate electrode should be placed directly at the pipe crossing point. If THERE IS a problem about the location of the crossing, the position of the crossing can be located with a pipe locator, and the effect of the cathode current on the external pipe is obvious.
How to reduce the interference of stray current
There ARE MANY WAYS TO REDUCE OR ELIMINATE STRAY CURRENT INTERFERENCE IN CATHODE-PROTECTION EQUIPMENT, SUCH AS CONNECTIONS THAT CAUSE PIPE DAMAGE, THE USE OF SACRIFICIAL ANODES AT INTERSECTIONS, THE USE OF COATINGS, AND THE USE OF ELECTRICAL SHIELDING. But these fixes are so complex and expensive that it may be more economical to reinstall the broken rectifier