Detection of Unauthorized Construction Equipment in Pipeline Right-of-Ways

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 an 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 performed in the second quarter of the project includes design of the instrument, selection of the key components, and beginning programming of the custom optical time domain reflectometer. Work included an assessment of two other approaches to measuring strain and vibrations in an extended optical fiber sensor.iii

Novel technique to calculate the effect of electromagnetic field of HVTL on the metallic pipelines by using EMTP program

“…The software uses the currents obtained from the EMTP in which the short circuit cases are simulated as a function of time to determine the metallic pipeline induced voltage. The computer results have been verified by the following formula (Power line induced AC, 1983;Dommel, H.W., discussion IEEE Working Group, 1974;Huebler, 2002):…”

“…The mutual impedance Z m can be expressed as by IEEE formula (H.W. Dommel, discussion IEEE Working Group, 1974;Huebler, 2002): The effect of electromagnetic field of HVTL…”

“…where f is frequency in Hz, m is free space permeability ¼ 4p £ 10 2 7 H/m, r is earth resistivity in Vm, D is the distance from transmission line to metallic pipeline in m, DR c and DX c are only roughly 1 percent of the value of Z m and are neglected in this study (Huebler, 2002). The induced voltage due to three-phase system can be calculated by the relation:…”