Mitigating Pipeline AC Interference Using Numerical Modeling and Continuous AC Voltage Monitoring

Abstract With the rapid construction of high voltage alternating current (AC) transmission lines, AC interference problem is becoming a new threat to the pipeline safety, especially for pipelines coated with high quality coating, such as 3PE+. Solid State DC Decoupler and Zinc ribbon groundbed AC mitigation system is the most commonly used mitigation method. But the locations of the mitigation system and the size of the zinc ribbon grounding system still remains a problem for most engineers. In this paper, numerical modeling software is used to fit the real field AC interference data to verify the rationality of related boundary settings. Then possible AC mitigation solutions are evaluated and optimized based on the verified software boundary settings. When it comes to field application, continuous pipe to soil (P/S) AC voltage monitoring units were installed at typical test stations to simultaneously obtain how AC voltage changes with installation. The AC mitigation practice showed that numerical modeling is a great tool for solution design and mitigation effectiveness evaluation, which can eliminate unnecessary mitigation points and to control the cost. Simultaneous AC potential monitoring at typical test stations will provide a complete data record, which can provide engineer a deep understanding how each mitigation point influences the entire AC voltage distribution along the affected pipeline.