Calculation

ISO 21857 - Evaluating DC Stray Current Voltages

ISO 21857 - Evaluating DC Stray Current Voltages

Interference from dc traction systems can result in pipe-to-soil potentials outside of the acceptable limits.

The Q method is an established procedure for evaluating the time varying potentials and empirical guidelines have been developed to allow a judgement of the corrosion risk caused by the interference.

The method can be used to evaluate current densities as well as potentials.