Detection of Stray Currents

The magnitude of current leaving (or entering) a buried pipe from whatever source can be calculated by measuring the potential difference between a position on the soil surface directly over the pipe and a position on the soil surface some distance away and at right angles to the pipe. If A( ) is the measured potential difference, p the resistivity of soil, h the depth of pipe below the surface, and y the distance along the soil surface over which the potential difference is measured, we obtain 

An outer reference electrode (+) with respect to a (-) reference electrode directly over the pipe corresponds to current entering the pipe. 

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Detection of Stray Currents Static stray currents of a pipeline can be detected by analy2ing pipe-to-soil potentials. The graph in Fig. 13 shows a pipeline with no interference. Figure 14 shows a potential plot for a coated pipeline with stray current interference. Interference may be... 

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