Need: The joint use of common corridors for overhead electric power transmission lines and buried natural gas transmission pipelines is increasing. While many benefits accrue from the sharing of corridors, the coupling of electromagnetic energy onto the
natural gas transmission pipelines is an undesired consequence of this joint usage. The steady-state pipeline voltage that can result may require mitigation as a safety measure.Many common corridors include multiple power lines and pipelines with complexities such as bonds or crossovers between the pipelines and terminating pipelines or insulators.
Benefit: This project has resulted in the development of the methodology and techniques for analyzing such complex common corridor coupling problems. Field tests were conducted to verify key aspects of the analysis. Two complementary methods have been developed for solving coupling problems on common corridors: A handbook that provides simplified procedures and graphical aids that can be used to analyze many less complex common corridor concerns and a computer program that provides the means for analyzing a wide range of more complex configurations.
Result: The program results are fully documented in a four-volume set. These volumes respectively present the analysis and research efforts, the simplified graphical analysis, the instructions for use of the computer program, and the results of a special mitigation study.
Volume 1 details the development of the analytic methods and describes data from field tests, which were used to verify the accuracy of the results.
Volume 2 is a handbook containing graphic solutions convenient for use by field personnel or others not having access to a computer.
Volume 3 is a user's guide for the computer program PIPELINE with examples of its use.
Volume 4 contains details on a new method of mitigating induced voltage on pipelines by coupling them with a conductor buried in parallel. This is especially useful in high-resistivity soil areas where conventional grounding may not be effective. A field demon-stration of this mitigation method that took place in California's Mohave Desert is also described.
The results of this project again demonstrate the value of cooperative research in order to solve technical problems of a multi-industry nature.
