Effects of harmonic induction on metallic pipeline caused by overhead power lines

The industrial standards for dealing with the pipeline AC induction issue have been well established, and the limits for preventing the metallic pipeline from the AC induction have been specified. However, these standards only focus on 50/60 Hz induction. The noticeable harmonic induction on pipelines has been revealed by various field measurements and theoretical analysis with the rapidly increased application of nonlinear loads and devices in power systems. The harmonics are always considered a steady-state phenomenon. The major concerns of the pipeline AC induction in steady-state include touch voltage and pipeline corrosion. The limits for dealing with harmonic induction may not be the same as those for 50/60 Hz induction because both touch voltage and pipeline corrosion are frequency dependent. In this study, the AC induction limits for harmonics are investigated and proposed through analysis, simulations, and experiments. The results show that the AC induction limits for an individual harmonic are slightly stricter than or comparable with those for to the 50/60 Hz ones. However, the accumulative induction effect due to multiple frequencies, which is the practical case, is much more severe than that due to an individual frequency. A case study using field measurement suggests that the harmonic induction effect on the pipeline should be included in the AC induction coordination assessment.

Automated summary

This study investigates and proposes AC induction limits for harmonics through analysis, simulations, and experiments. The results show that the cumulative induction effect due to multiple frequencies is more severe than that due to an individual frequency, suggesting the inclusion of harmonic induction effect in AC induction coordination assessment.