AC Interference Prediction for a New 8 in (203 mm) Gas Pipeline in Guadalajara City

摘要

When a pipeline shares the right of way with AC transmission lines, an inductive coupling may lead to alternating electrical current flow through the pipeline and a potential difference between the pipeline and the ground, which implies certain risks associated with public safety and the integrity of the pipeline itself. The effects of AC interference can be detected and characterized by direct field measurements on the pipeline and the ground, but the uncertainty of the results is increased when the pipeline has not yet been installed. A new 8" (203mm) pipeline for natural gas distribution will be built in the city of Guadalajara (Mexico). The constructor has identified a segment of 1.5 km length where the pipeline will share the right of way with high voltage transmission lines, and because the pipeline is in a High Consequence Area (HCA), the priority is to predict potential risks and determining interference mitigation mechanisms to increase the operational reliability of the pipeline even before it is built. This paper presents the different approaches made to predict the effects related to interference by electromagnetic induction, including field tests and analytical procedures based on phasor algebra to design a solution that can be integrated into the construction process of the pipeline. The results obtained by different methods show substantial variations mainly due to the different conditions of operation of high voltage lines and the criteria on which each methodology is based. These differences do not reject any of the analysis presented, but complement each other and allow a wide view of the different scenarios that may occur over time.