Abstract

Natural gas transmission companies mark the right-of-way areas where pipelines are buried with warning signs to prevent accidental third-party damage. Nevertheless, pipelines are sometimes damaged by third-party construction equipment. A single incident can be devastating, causing death and millions of dollars of property loss. This damage would be prevented if potentially hazardous construction equipment could be detected, identified, and an alert given before the pipeline was damaged. The Gas Technology Institute (GTI) is developing a system to solve this problem by using an optical fiber as a distributed sensor and interrogating the fiber with a custom optical time domain reflectometer. Key issues are the ability to detect encroachment and the ability to discriminate among potentially hazardous and benign encroachments. The work continues on improving the signal-to-noise ratio of the technique. We are now able to detect weights sitting on the Hergalite fiber of as low as 0.2 pound. Detection of load fluctuations with frequencies greater than 1 Hertz is also possible. We have also purchased a brighter diode laser for use with the multimode fibers that should improve our sensitivity by a factor of ten. Document type: Report