Abstract
Alternating Current (AC) Interference and Mitigation (ACIM) is becoming an increasingly common occurrence in the pipeline industry. This paper describes the challenges associated with coordinating the modelling, design, and installation of ACIM systems for a complex ACIM project located in Edmonton, Alberta, Canada, with a final total installed cost in excess of $40,000,000 CAD. The project consisted of a 65 kilometer long double circuit 500 kilovolt (kV) overhead transmission line being installed in a heavily congested right-of-way corridor with more than 80 pipelines owned by variety of operators. Also included were several other overhead transmission lines (138 kV to 500 kV) throughout the project area. The transmission line was built in a very heavily congested pipeline corridor in a government controlled transportation and utilities corridor (TUC). As an added challenge, substantial road work was being completed in the area concurrently. The model predicted that the affected pipelines were expected to experience significant steady state, fault state, and AC corrosion interference issues prior to AC mitigation installation. The AC interference risk assessment, modelling, mitigation design, and mitigation installation process involved coordination between large pipeline owner companies and their individual consultants. The process of modelling AC interference and designing AC mitigation for so many pipelines that all interact with and affect each other will be discussed. Lessons learned for different aspects of the project will also be discussed.
