Application of a stray current monitoring system base upon virtual instrument

Stray current corrosion (SCC) is one of the most severe forms of electrochemical corrosion. In the paper, the mechanism and character of stray current from DC electric traction systems and its influence upon buried pipe were briefly introduced. The stray current testing methods and testing equipments were reviewed. A new system for monitoring the stray current, based upon virtual instrument, was put forward. The proposed system has some advantages such as real-time display, frequency control, and automatic data storage. The pipe-soil potentials of a gas pipeline, located in the neighboring area and parallel to the rail transit powered by a DC source in Shanghai, were tested by means of proposed system. Actual results show that stray current corrosion of underground gas pipeline is existed, some protective measures must be done to eliminate the corrosion, and the feasibility of the system has been proved.