Dynamic Stray Current Analysis for New Direct Current-Powered transit Systems

摘要

The dynamic stray current tests described above are the only way to determine the amount of stray current (A/1,000 ft) emanating from a DC-powered transit system once train operations begin. Re-testing is never done because of the cost and lengthy time required and because retesting interrupts revenue service. The data are useful for evaluating stray current control measures and effects with a certain configuration of train characteristics, substation spacing, and rail-to-ground resistance values. Design criteria can be adjusted for future extensions and for other systems-and not necessarily in a more conservative direction-because economics are always a concern with corrosion control. Data are also used as a continuing adjustor of design criteria targets, as well as practically achievable and anticipated stray current levels. Results also define the stray current corrosion characteristics of the tested system for decades to come, provided that good maintenance procedures are followed.