Abstract: As the development of DC transit systems continues, many of the buried pipelines and metal structures close to the metro system have experienced accelerated corrosion by the dynamic DC stray current. Because of the dynamic feature of the stray currents, monitoring the effect of the dynamic stray current on the corrosion of the buried structures has been a challenging task. This invention discloses a method to use a multielectrode system to measure the effect of dynamic stray currents on the corrosion of a metal structure or buried pipeline. The method also measures the effectiveness of cathodic protection under the influence of stray current. High-voltage power transmission lines that produce a changing magnetic field, which in turn produces an alternating current flowing through the berried pipe or other structures that run in parallel with the transmission lines. The method disclosed in this invention may also be used to detect the effect of the interference of the alternating current.

Abstract: As the development of DC transit systems continues, many of the buried pipelines and metal structures close to the metro system have experienced accelerated corrosion by the dynamic DC stray current. Because of the dynamic feature of the stray currents, monitoring the effect of the dynamic stray current on the corrosion of the buried structures has been a challenging task. This invention discloses a method to use a multielectrode system to measure the effect of dynamic stray currents on the corrosion of a metal structure or buried pipeline. The method also measures the effectiveness of cathodic protection under the influence of stray current. High-voltage power transmission lines that produce a changing magnetic field, which in turn produces an alternating current flowing through the buried pipe or other structures that run in parallel with the transmission lines.