Test method of AC interference parameters for pipeline adjacent power transmission lines

Power transmission line could cause AC interference corrosion of the buried pipeline when it shares a corridor with the pipeline. Because the measurement methods of traditional electric parameters are not suitable for measuring the AC interference parameters of pipeline suffered from AC interference, they can not be used to evaluate the level of AC interference. In this paper, the test methods of AC interference parameters, including the method of electrochemical measurement and corrosion rate estimation in laboratory, and field measurement method of pipe-soil potential, AC current density, the ratio of AC/DC current density, are introduced. As an important indicator of AC interference, the measurement method of current density is especially addressed. The design and installation method of coupon used to measure the AC interference parameters in field are illustrated in detail. The two indispensable parameters (AC current density, the ratio of AC/DC current density) for the evaluation of AC interference corrosion can not be directly measured from the pipeline, the measurement methods of electric and electrochemical parameters with specimens are recommended.