long-range pipeline monitoring by distributed fiber optic sensing

مستشعر درجة حرارة الألياف البصرية, نظام مراقبة ذكي, الشركة المصنعة للألياف البصرية الموزعة في الصين

There are some minor defects in the production process of natural gas transmission pipelines. Under long-term transmission loads and the high temperature and corrosive environment of the transmission medium, pipeline corrosion will accelerate and worsen, ultimately leading to pipeline damage and leakage accidents, causing huge direct economic losses, and triggering a series of secondary disasters, such as fires and environmental pollution, posing a threat to people’s life safety. لذلك, safety issues during natural gas pipeline transportation, especially online real-time leak detection of natural gas pipelines, have always been a top priority that needs to be considered in safety production.

حالا, there are many leakage monitoring methods for gas pipelines, which can be divided into mass/volume balance method, applied statistical method, negative pressure wave method, transient model method, distributed fiber optic method, الخ. based on the different gas flow parameters monitored inside the pipeline. The gas pipeline leakage detection method based on distributed fiber optic sensing has been widely studied and applied due to its advantages of good sensitivity, دقة عالية لتحديد المواقع, short detection time, strong adaptability, and long system life. When a gas pipeline ruptures at a certain point and leaks, it will disrupt the normal pressure balance in the pipeline, release the elastic energy of the fluid in the pipeline system, and cause instantaneous oscillation to produce sound waves. The leakage sound wave is generated by the excited energy of gas leakage, and is a continuously emitted signal with a frequency of several hundred kHz, mainly propagating along the pipe wall. By using optical fibers installed along the pipeline, this acoustic signal can be monitored and collected. By extracting and identifying the characteristics of the acoustic signal, it can be determined whether there is a leak in the pipeline.

Advantages of distributed fiber optic natural gas transmission pipeline security vibration monitoring technology:

1. Continuous distributed measurement of temperature and vibration without measurement blind spots

2. Simultaneous detection and accurate localization of multiple events

3. Fiber optic is a sensor that combines transmission and sensing

4. 40 kilometers of ultra long measurement distance, rich measurement information

5. سرعة استجابة سريعة, alarm within 1 second

6. Optical signal transmission, completely electrically insulated, resistant to electromagnetic interference

7. Intrinsic safety, suitable for long-term operation in flammable and explosive environments

8. Stable and reliable measurement with low false alarm rate

9. Long service life of optical fibers, يصل إلى 30 years maintenance free

Performance characteristics of distributed fiber optic vibration monitoring system:

Long temperature distance: 40km

وقت استجابة سريع: typical 1 second

High positioning accuracy: 2-50m

High sensitivity: can perceive vibrations within 40m around the optical cable

Simultaneous monitoring of vibration and temperature

Online monitoring function for fiber optic faults

Friendly user software that provides a visual interface

 

Performance indicators of distributed fiber optic vibration monitoring system:

Technical performance

Fiber type single-mode fiber

Measurement distance of 40km

Positioning accuracy of 1m~50m

Sampling interval of 0.5m

Measurement time typical 1 second

Measurement channels 1, 2, 4, 8

Vibration signal bandwidth ≤ 5KHz

Vibration measurement sensitivity ≤ 40m

Temperature measurement range -100 ℃~200 ℃