Criterion for pipeline AC interference corrosion in the public energy corridor

Construction of high-voltage power lines and AC electrified railways speed up the formation of utility energy corridor. This causes AC interference corrosion problems due to being crossed with, parallel to, or near buried oil and gas pipelines, which may threaten the safe operation of pipeline. Criterions and relevant standards for AC interference corrosion are promulgated in countries worldwide. For pipeline systems without cathodic protection (CP), AC induction voltage and AC current density are more likely to be used. For pipeline systems with CP, the density ratio between AC current and DC current is more likely to be used. For new pipeline systems, the most direct method for avoiding AC interference corrosion in the public energy corridor is to remove AC interference sources from high-voltage power lines, electrified railways and other buried pipelines. For in-service pipeline systems, the AC interference corrosion is reduced by shielding or draining measures, or other measures. There are still many cognitive gaps to be filled on the effects of AC corrosion on CP systems and the use of AC voltage or AC current density for evaluation of AC corrosion rates. Meanwhile, standards for safe distance between high-voltage power lines, electrified railways, and oil & gas pipelines should be researched and developed based on the local conditions in order to meet the requirements in China.